-<chapter id="quick-start">
-<title>Quick Start </title>
-
-<para>
-In this section, we will test the system by indexing a small set of sample
-GILS records that are included with the software distribution. Go to the
-<literal remap="tt">test/gils</literal> subdirectory of the distribution archive. There you will
-find a configuration
-file named <literal remap="tt">zebra.cfg</literal> with the following contents:
-
-<screen>
-# Where are the YAZ tables located.
-profilePath: ../../../yaz/tab ../../tab
-
-# Files that describe the attribute sets supported.
-attset: bib1.att
-attset: gils.att
-</screen>
-
-</para>
-
-<para>
-Now, edit the file and set <literal remap="tt">profilePath</literal> to the path of the
-YAZ profile tables (sub directory <literal remap="tt">tab</literal> of the YAZ distribution
-archive).
-</para>
-
-<para>
-The 48 test records are located in the sub directory <literal remap="tt">records</literal>.
-To index these, type:
-
-<screen>
-$ ../../index/zebraidx -t grs.sgml update records
-</screen>
-
-</para>
-
-<para>
-In the command above the option <literal remap="tt">-t</literal> specified the record
-type — in this case <literal remap="tt">grs.sgml</literal>. The word <literal remap="tt">update</literal> followed
-by a directory root updates all files below that directory node.
-</para>
-
-<para>
-If your indexing command was successful, you are now ready to
-fire up a server. To start a server on port 2100, type:
-
-<screen>
-$ ../../index/zebrasrv tcp:@:2100
-</screen>
-
-</para>
-
-<para>
-The Zebra index that you have just created has a single database
-named <literal remap="tt">Default</literal>. The database contains records structured according to
-the GILS profile, and the server will
-return records in either either USMARC, GRS-1, or SUTRS depending
-on what your client asks
-for.
-</para>
-
-<para>
-To test the server, you can use any Z39.50 client (1992 or later). For
-instance, you can use the demo client that comes with YAZ: Just cd to
-the <literal remap="tt">client</literal> subdirectory of the YAZ distribution and type:
-</para>
-
-<para>
-
-<screen>
-$ client tcp:localhost:2100
-</screen>
-
-</para>
-
-<para>
-When the client has connected, you can type:
-</para>
-
-<para>
-
-<screen>
-Z> find surficial
-Z> show 1
-</screen>
-
-</para>
-
-<para>
-The default retrieval syntax for the client is USMARC. To try other
-formats for the same record, try:
-</para>
-
-<para>
-
-<screen>
-Z>format sutrs
-Z>show 1
-Z>format grs-1
-Z>show 1
-Z>elements B
-Z>show 1
-</screen>
-
-</para>
-
-<para>
-<emphasis remap="it">NOTE: You may notice that more fields are returned when your
-client requests SUTRS or GRS-1 records. When retrieving GILS records,
-this is normal - not all of the GILS data elements have mappings in
-the USMARC record format.</emphasis>
-</para>
-
-<para>
-If you've made it this far, there's a good chance that
-you've got through the compilation OK.
-</para>
-
-</chapter>
-
<chapter id="administration">
-<title>Administrating Zebra</title>
-
-<para>
-Unlike many simpler retrieval systems, Zebra supports safe, incremental
-updates to an existing index.
-</para>
-
-<para>
-Normally, when Zebra modifies the index it reads a number of records
-that you specify.
-Depending on your specifications and on the contents of each record
-one the following events take place for each record:
-<variablelist>
-
-<varlistentry>
-<term>Insert</term>
-<listitem>
-<para>
-The record is indexed as if it never occurred
-before. Either the Zebra system doesn't know how to identify the record or
-Zebra can identify the record but didn't find it to be already indexed.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>Modify</term>
-<listitem>
-<para>
-The record has already been indexed. In this case
-either the contents of the record or the location (file) of the record
-indicates that it has been indexed before.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>Delete</term>
-<listitem>
-<para>
-The record is deleted from the index. As in the
-update-case it must be able to identify the record.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-<para>
-Please note that in both the modify- and delete- case the Zebra
-indexer must be able to generate a unique key that identifies the record in
-question (more on this below).
-</para>
-
-<para>
-To administrate the Zebra retrieval system, you run the
-<literal remap="tt">zebraidx</literal> program. This program supports a number of options
-which are preceded by a minus, and a few commands (not preceded by
-minus).
-</para>
-
-<para>
-Both the Zebra administrative tool and the Z39.50 server share a
-set of index files and a global configuration file. The
-name of the configuration file defaults to <literal remap="tt">zebra.cfg</literal>.
-The configuration file includes specifications on how to index
-various kinds of records and where the other configuration files
-are located. <literal remap="tt">zebrasrv</literal> and <literal remap="tt">zebraidx</literal> <emphasis>must</emphasis>
-be run in the directory where the configuration file lives unless you
-indicate the location of the configuration file by option
-<literal remap="tt">-c</literal>.
-</para>
-
-<sect1 id="record-types">
-<title>Record Types</title>
-
-<para>
-Indexing is a per-record process, in which either insert/modify/delete
-will occur. Before a record is indexed search keys are extracted from
-whatever might be the layout the original record (sgml,html,text, etc..).
-The Zebra system currently supports two fundamantal types of records:
-structured and simple text.
-To specify a particular extraction process, use either the
-command line option <literal remap="tt">-t</literal> or specify a
-<literal remap="tt">recordType</literal> setting in the configuration file.
-</para>
-
-</sect1>
-
-<sect1 id="configuration-file">
-<title>The Zebra Configuration File</title>
-
-<para>
-The Zebra configuration file, read by <literal remap="tt">zebraidx</literal> and
-<literal remap="tt">zebrasrv</literal> defaults to <literal remap="tt">zebra.cfg</literal> unless specified
-by <literal remap="tt">-c</literal> option.
-</para>
-
-<para>
-You can edit the configuration file with a normal text editor.
-parameter names and values are seperated by colons in the file. Lines
-starting with a hash sign (<literal remap="tt">#</literal>) are treated as comments.
-</para>
-
-<para>
-If you manage different sets of records that share common
-characteristics, you can organize the configuration settings for each
-type into "groups".
-When <literal remap="tt">zebraidx</literal> is run and you wish to address a given group
-you specify the group name with the <literal remap="tt">-g</literal> option. In this case
-settings that have the group name as their prefix will be used
-by <literal remap="tt">zebraidx</literal>. If no <literal remap="tt">-g</literal> option is specified, the settings
-with no prefix are used.
-</para>
-
-<para>
-In the configuration file, the group name is placed before the option
-name itself, separated by a dot (.). For instance, to set the record type
-for group <literal remap="tt">public</literal> to <literal remap="tt">grs.sgml</literal> (the SGML-like format for structured
-records) you would write:
-</para>
-
-<para>
-
-<screen>
-public.recordType: grs.sgml
-</screen>
-
-</para>
-
-<para>
-To set the default value of the record type to <literal remap="tt">text</literal> write:
-</para>
-
-<para>
-
-<screen>
-recordType: text
-</screen>
-
-</para>
-
-<para>
-The available configuration settings are summarized below. They will be
-explained further in the following sections.
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term><emphasis remap="it">group</emphasis>.recordType[<emphasis remap="it">.name</emphasis>]</term>
-<listitem>
-<para>
-Specifies how records with the file extension <emphasis remap="it">name</emphasis> should
-be handled by the indexer. This option may also be specified
-as a command line option (<literal remap="tt">-t</literal>). Note that if you do not
-specify a <emphasis remap="it">name</emphasis>, the setting applies to all files. In general,
-the record type specifier consists of the elements (each
-element separated by dot), <emphasis remap="it">fundamental-type</emphasis>,
-<emphasis remap="it">file-read-type</emphasis> and arguments. Currently, two
-fundamental types exist, <literal remap="tt">text</literal> and <literal remap="tt">grs</literal>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term><emphasis remap="it">group</emphasis>.recordId</term>
-<listitem>
-<para>
-Specifies how the records are to be identified when updated. See
-section <xref linkend="locating-records"/>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term><emphasis remap="it">group</emphasis>.database</term>
-<listitem>
-<para>
-Specifies the Z39.50 database name.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term><emphasis remap="it">group</emphasis>.storeKeys</term>
-<listitem>
-<para>
-Specifies whether key information should be saved for a given
-group of records. If you plan to update/delete this type of
-records later this should be specified as 1; otherwise it
-should be 0 (default), to save register space. See section
-<xref linkend="file-ids"/>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term><emphasis remap="it">group</emphasis>.storeData</term>
-<listitem>
-<para>
-Specifies whether the records should be stored internally
-in the Zebra system files. If you want to maintain the raw records yourself,
-this option should be false (0). If you want Zebra to take care of the records
-for you, it should be true(1).
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>register</term>
-<listitem>
-<para>
-Specifies the location of the various register files that Zebra uses
-to represent your databases. See section
-<xref linkend="register-location"/>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>shadow</term>
-<listitem>
-<para>
-Enables the <emphasis remap="it">safe update</emphasis> facility of Zebra, and tells the system
-where to place the required, temporary files. See section
-<xref linkend="shadow-registers"/>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>lockDir</term>
-<listitem>
-<para>
-Directory in which various lock files are stored.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>keyTmpDir</term>
-<listitem>
-<para>
-Directory in which temporary files used during zebraidx' update
-phase are stored.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>setTmpDir</term>
-<listitem>
-<para>
-Specifies the directory that the server uses for temporary result sets.
-If not specified <literal remap="tt">/tmp</literal> will be used.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>profilePath</term>
-<listitem>
-<para>
-Specifies the location of profile specification files.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>attset</term>
-<listitem>
-<para>
-Specifies the filename(s) of attribute set files for use in
-searching. At least the Bib-1 set should be loaded (<literal remap="tt">bib1.att</literal>).
-The <literal remap="tt">profilePath</literal> setting is used to look for the specified files.
-See section <xref linkend="attset-files"/>
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>memMax</term>
-<listitem>
-<para>
-Specifies size of internal memory to use for the zebraidx program. The
-amount is given in megabytes - default is 4 (4 MB).
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-</sect1>
-
-<sect1 id="locating-records">
-<title>Locating Records</title>
-
-<para>
-The default behaviour of the Zebra system is to reference the
-records from their original location, i.e. where they were found when you
-ran <literal remap="tt">zebraidx</literal>. That is, when a client wishes to retrieve a record
-following a search operation, the files are accessed from the place
-where you originally put them - if you remove the files (without
-running <literal remap="tt">zebraidx</literal> again, the client will receive a diagnostic
-message.
-</para>
-
-<para>
-If your input files are not permanent - for example if you retrieve
-your records from an outside source, or if they were temporarily
-mounted on a CD-ROM drive,
-you may want Zebra to make an internal copy of them. To do this,
-you specify 1 (true) in the <literal remap="tt">storeData</literal> setting. When
-the Z39.50 server retrieves the records they will be read from the
-internal file structures of the system.
-</para>
-
-</sect1>
-
-<sect1 id="simple-indexing">
-<title>Indexing with no Record IDs (Simple Indexing)</title>
-
-<para>
-If you have a set of records that are not expected to change over time
-you may can build your database without record IDs.
-This indexing method uses less space than the other methods and
-is simple to use.
-</para>
-
-<para>
-To use this method, you simply omit the <literal remap="tt">recordId</literal> entry
-for the group of files that you index. To add a set of records you use
-<literal remap="tt">zebraidx</literal> with the <literal remap="tt">update</literal> command. The
-<literal remap="tt">update</literal> command will always add all of the records that it
-encounters to the index - whether they have already been indexed or
-not. If the set of indexed files change, you should delete all of the
-index files, and build a new index from scratch.
-</para>
-
-<para>
-Consider a system in which you have a group of text files called
-<literal remap="tt">simple</literal>. That group of records should belong to a Z39.50 database
-called <literal remap="tt">textbase</literal>. The following <literal remap="tt">zebra.cfg</literal> file will suffice:
-</para>
-
-<para>
-
-<screen>
-profilePath: /usr/local/yaz
-attset: bib1.att
-simple.recordType: text
-simple.database: textbase
-</screen>
-
-</para>
-
-<para>
-Since the existing records in an index can not be addressed by their
-IDs, it is impossible to delete or modify records when using this method.
-</para>
-
-</sect1>
-
-<sect1 id="file-ids">
-<title>Indexing with File Record IDs</title>
-
-<para>
-If you have a set of files that regularly change over time: Old files
-are deleted, new ones are added, or existing files are modified, you
-can benefit from using the <emphasis remap="it">file ID</emphasis> indexing methodology. Examples
-of this type of database might include an index of WWW resources, or a
-USENET news spool area. Briefly speaking, the file key methodology
-uses the directory paths of the individual records as a unique
-identifier for each record. To perform indexing of a directory with
-file keys, again, you specify the top-level directory after the
-<literal remap="tt">update</literal> command. The command will recursively traverse the
-directories and compare each one with whatever have been indexed before in
-that same directory. If a file is new (not in the previous version of
-the directory) it is inserted into the registers; if a file was
-already indexed and it has been modified since the last update,
-the index is also modified; if a file has been removed since the last
-visit, it is deleted from the index.
-</para>
-
-<para>
-The resulting system is easy to administrate. To delete a record you
-simply have to delete the corresponding file (say, with the <literal remap="tt">rm</literal>
-command). And to add records you create new files (or directories with
-files). For your changes to take effect in the register you must run
-<literal remap="tt">zebraidx update</literal> with the same directory root again. This mode
-of operation requires more disk space than simpler indexing methods,
-but it makes it easier for you to keep the index in sync with a
-frequently changing set of data. If you combine this system with the
-<emphasis remap="it">safe update</emphasis> facility (see below), you never have to take your
-server offline for maintenance or register updating purposes.
-</para>
-
-<para>
-To enable indexing with pathname IDs, you must specify <literal remap="tt">file</literal> as
-the value of <literal remap="tt">recordId</literal> in the configuration file. In addition,
-you should set <literal remap="tt">storeKeys</literal> to <literal remap="tt">1</literal>, since the Zebra
-indexer must save additional information about the contents of each record
-in order to modify the indices correctly at a later time.
-</para>
-
-<para>
-For example, to update records of group <literal remap="tt">esdd</literal> located below
-<literal remap="tt">/data1/records/</literal> you should type:
-
-<screen>
-$ zebraidx -g esdd update /data1/records
-</screen>
-
-</para>
-
-<para>
-The corresponding configuration file includes:
-
-<screen>
-esdd.recordId: file
-esdd.recordType: grs.sgml
-esdd.storeKeys: 1
-</screen>
-
-</para>
-
-<para>
-<emphasis>Important note: You cannot start out with a group of records with simple
-indexing (no record IDs as in the previous section) and then later
-enable file record Ids. Zebra must know from the first time that you
-index the group that
-the files should be indexed with file record IDs.</emphasis>
-</para>
-
-<para>
-You cannot explicitly delete records when using this method (using the
-<emphasis remap="bf">delete</emphasis> command to <literal remap="tt">zebraidx</literal>. Instead
-you have to delete the files from the file system (or move them to a
-different location)
-and then run <literal remap="tt">zebraidx</literal> with the <emphasis remap="bf">update</emphasis> command.
-</para>
-
-</sect1>
-
-<sect1 id="generic-ids">
-<title>Indexing with General Record IDs</title>
-
-<para>
-When using this method you construct an (almost) arbritrary, internal
-record key based on the contents of the record itself and other system
-information. If you have a group of records that explicitly associates
-an ID with each record, this method is convenient. For example, the
-record format may contain a title or a ID-number - unique within the group.
-In either case you specify the Z39.50 attribute set and use-attribute
-location in which this information is stored, and the system looks at
-that field to determine the identity of the record.
-</para>
-
-<para>
-As before, the record ID is defined by the <literal remap="tt">recordId</literal> setting
-in the configuration file. The value of the record ID specification
-consists of one or more tokens separated by whitespace. The resulting
-ID is
-represented in the index by concatenating the tokens and separating them by
-ASCII value (1).
-</para>
-
-<para>
-There are three kinds of tokens:
-<variablelist>
-
-<varlistentry>
-<term>Internal record info</term>
-<listitem>
-<para>
-The token refers to a key that is
-extracted from the record. The syntax of this token is
-<literal remap="tt">(</literal> <emphasis>set</emphasis> <literal remap="tt">,</literal> <emphasis>use</emphasis> <literal remap="tt">)</literal>, where <emphasis>set</emphasis> is the
-attribute set name <emphasis>use</emphasis> is the name or value of the attribute.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>System variable</term>
-<listitem>
-<para>
-The system variables are preceded by
-
-<screen>
-$
-</screen>
- and immediately followed by the system variable name, which
-may one of
-<variablelist>
-
-<varlistentry>
-<term>group</term>
-<listitem>
-<para>
-Group name.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>database</term>
-<listitem>
-<para>
-Current database specified.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>type</term>
-<listitem>
-<para>
-Record type.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>Constant string</term>
-<listitem>
-<para>
-A string used as part of the ID — surrounded
-by single- or double quotes.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-<para>
-For instance, the sample GILS records that come with the Zebra
-distribution contain a unique ID in the data tagged Control-Identifier.
-The data is mapped to the Bib-1 use attribute Identifier-standard
-(code 1007). To use this field as a record id, specify
-<literal remap="tt">(bib1,Identifier-standard)</literal> as the value of the
-<literal remap="tt">recordId</literal> in the configuration file.
-If you have other record types that uses the same field for a
-different purpose, you might add the record type
-(or group or database name) to the record id of the gils
-records as well, to prevent matches with other types of records.
-In this case the recordId might be set like this:
-
-<screen>
-gils.recordId: $type (bib1,Identifier-standard)
-</screen>
-
-</para>
-
-<para>
-(see section <xref linkend="data-model"/>
-for details of how the mapping between elements of your records and
-searchable attributes is established).
-</para>
-
-<para>
-As for the file record ID case described in the previous section,
-updating your system is simply a matter of running <literal remap="tt">zebraidx</literal>
-with the <literal remap="tt">update</literal> command. However, the update with general
-keys is considerably slower than with file record IDs, since all files
-visited must be (re)read to discover their IDs.
-</para>
-
-<para>
-As you might expect, when using the general record IDs
-method, you can only add or modify existing records with the <literal remap="tt">update</literal>
-command. If you wish to delete records, you must use the,
-<literal remap="tt">delete</literal> command, with a directory as a parameter.
-This will remove all records that match the files below that root
-directory.
-</para>
-
-</sect1>
-
-<sect1 id="register-location">
-<title>Register Location</title>
-
-<para>
-Normally, the index files that form dictionaries, inverted
-files, record info, etc., are stored in the directory where you run
-<literal remap="tt">zebraidx</literal>. If you wish to store these, possibly large, files
-somewhere else, you must add the <literal remap="tt">register</literal> entry to the
-<literal remap="tt">zebra.cfg</literal> file. Furthermore, the Zebra system allows its file
-structures to
-span multiple file systems, which is useful for managing very large
-databases.
-</para>
-
-<para>
-The value of the <literal remap="tt">register</literal> setting is a sequence of tokens.
-Each token takes the form:
-
-<screen>
-<emphasis>dir</emphasis><literal remap="tt">:</literal><emphasis>size</emphasis>.
-</screen>
-
-The <emphasis>dir</emphasis> specifies a directory in which index files will be
-stored and the <emphasis>size</emphasis> specifies the maximum size of all
-files in that directory. The Zebra indexer system fills each directory
-in the order specified and use the next specified directories as needed.
-The <emphasis>size</emphasis> is an integer followed by a qualifier
-code, <literal remap="tt">M</literal> for megabytes, <literal remap="tt">k</literal> for kilobytes.
-</para>
-
-<para>
-For instance, if you have allocated two disks for your register, and
-the first disk is mounted
-on <literal remap="tt">/d1</literal> and has 200 Mb of free space and the
-second, mounted on <literal remap="tt">/d2</literal> has 300 Mb, you could
-put this entry in your configuration file:
-
-<screen>
-register: /d1:200M /d2:300M
-</screen>
-
-</para>
-
-<para>
-Note that Zebra does not verify that the amount of space specified is
-actually available on the directory (file system) specified - it is
-your responsibility to ensure that enough space is available, and that
-other applications do not attempt to use the free space. In a large production system,
-it is recommended that you allocate one or more filesystem exclusively
-to the Zebra register files.
-</para>
-
-</sect1>
-
-<sect1 id="shadow-registers">
-<title>Safe Updating - Using Shadow Registers</title>
-
-<sect2>
-<title>Description</title>
-
-<para>
-The Zebra server supports <emphasis remap="it">updating</emphasis> of the index structures. That is,
-you can add, modify, or remove records from databases managed by Zebra
-without rebuilding the entire index. Since this process involves
-modifying structured files with various references between blocks of
-data in the files, the update process is inherently sensitive to
-system crashes, or to process interruptions: Anything but a
-successfully completed update process will leave the register files in
-an unknown state, and you will essentially have no recourse but to
-re-index everything, or to restore the register files from a backup
-medium. Further, while the update process is active, users cannot be
-allowed to access the system, as the contents of the register files
-may change unpredictably.
-</para>
-
-<para>
-You can solve these problems by enabling the shadow register system in
-Zebra. During the updating procedure, <literal remap="tt">zebraidx</literal> will temporarily
-write changes to the involved files in a set of "shadow
-files", without modifying the files that are accessed by the
-active server processes. If the update procedure is interrupted by a
-system crash or a signal, you simply repeat the procedure - the
-register files have not been changed or damaged, and the partially
-written shadow files are automatically deleted before the new updating
-procedure commences.
-</para>
-
-<para>
-At the end of the updating procedure (or in a separate operation, if
-you so desire), the system enters a "commit mode". First,
-any active server processes are forced to access those blocks that
-have been changed from the shadow files rather than from the main
-register files; the unmodified blocks are still accessed at their
-normal location (the shadow files are not a complete copy of the
-register files - they only contain those parts that have actually been
-modified). If the commit process is interrupted at any point during the
-commit process, the server processes will continue to access the
-shadow files until you can repeat the commit procedure and complete
-the writing of data to the main register files. You can perform
-multiple update operations to the registers before you commit the
-changes to the system files, or you can execute the commit operation
-at the end of each update operation. When the commit phase has
-completed successfully, any running server processes are instructed to
-switch their operations to the new, operational register, and the
-temporary shadow files are deleted.
-</para>
-
-</sect2>
-
-<sect2>
-<title>How to Use Shadow Register Files</title>
-
-<para>
-The first step is to allocate space on your system for the shadow
-files. You do this by adding a <literal remap="tt">shadow</literal> entry to the <literal remap="tt">zebra.cfg</literal>
-file. The syntax of the <literal remap="tt">shadow</literal> entry is exactly the same as for
-the <literal remap="tt">register</literal> entry (see section <xref linkend="register-location"/>). The location of the shadow area should be
-<emphasis remap="it">different</emphasis> from the location of the main register area (if you
-have specified one - remember that if you provide no <literal remap="tt">register</literal>
-setting, the default register area is the
-working directory of the server and indexing processes).
-</para>
-
-<para>
-The following excerpt from a <literal remap="tt">zebra.cfg</literal> file shows one example of
-a setup that configures both the main register location and the shadow
-file area. Note that two directories or partitions have been set aside
-for the shadow file area. You can specify any number of directories
-for each of the file areas, but remember that there should be no
-overlaps between the directories used for the main registers and the
-shadow files, respectively.
-</para>
-
-<para>
-
-<screen>
-register: /d1:500M
-
-shadow: /scratch1:100M /scratch2:200M
-</screen>
-
-</para>
-
-<para>
-When shadow files are enabled, an extra command is available at the
-<literal remap="tt">zebraidx</literal> command line. In order to make changes to the system
-take effect for the users, you'll have to submit a
-"commit" command after a (sequence of) update
-operation(s). You can ask the indexer to commit the changes
-immediately after the update operation:
-</para>
-
-<para>
-
-<screen>
-$ zebraidx update /d1/records update /d2/more-records commit
-</screen>
-
-</para>
-
-<para>
-Or you can execute multiple updates before committing the changes:
-</para>
-
-<para>
-
-<screen>
-$ zebraidx -g books update /d1/records update /d2/more-records
-$ zebraidx -g fun update /d3/fun-records
-$ zebraidx commit
-</screen>
-
-</para>
-
-<para>
-If one of the update operations above had been interrupted, the commit
-operation on the last line would fail: <literal remap="tt">zebraidx</literal> will not let you
-commit changes that would destroy the running register. You'll have to
-rerun all of the update operations since your last commit operation,
-before you can commit the new changes.
-</para>
-
-<para>
-Similarly, if the commit operation fails, <literal remap="tt">zebraidx</literal> will not let
-you start a new update operation before you have successfully repeated
-the commit operation. The server processes will keep accessing the
-shadow files rather than the (possibly damaged) blocks of the main
-register files until the commit operation has successfully completed.
-</para>
-
-<para>
-You should be aware that update operations may take slightly longer
-when the shadow register system is enabled, since more file access
-operations are involved. Further, while the disk space required for
-the shadow register data is modest for a small update operation, you
-may prefer to disable the system if you are adding a very large number
-of records to an already very large database (we use the terms
-<emphasis remap="it">large</emphasis> and <emphasis remap="it">modest</emphasis> very loosely here, since every
-application will have a different perception of size). To update the system
-without the use of the the shadow files, simply run <literal remap="tt">zebraidx</literal> with
-the <literal remap="tt">-n</literal> option (note that you do not have to execute the
-<emphasis remap="bf">commit</emphasis> command of <literal remap="tt">zebraidx</literal> when you temporarily disable the
-use of the shadow registers in this fashion. Note also that, just as
-when the shadow registers are not enabled, server processes will be
-barred from accessing the main register while the update procedure
-takes place.
-</para>
-
-</sect2>
-
+ <title>Administrating &zebra;</title>
+ <!-- ### It's a bit daft that this chapter (which describes half of
+ the configuration-file formats) is separated from
+ "recordmodel-grs.xml" (which describes the other half) by the
+ instructions on running zebraidx and zebrasrv. Some careful
+ re-ordering is required here.
+ -->
+
+ <para>
+ Unlike many simpler retrieval systems, &zebra; supports safe, incremental
+ updates to an existing index.
+ </para>
+
+ <para>
+ Normally, when &zebra; modifies the index it reads a number of records
+ that you specify.
+ Depending on your specifications and on the contents of each record
+ one the following events take place for each record:
+ <variablelist>
+
+ <varlistentry>
+ <term>Insert</term>
+ <listitem>
+ <para>
+ The record is indexed as if it never occurred before.
+ Either the &zebra; system doesn't know how to identify the record or
+ &zebra; can identify the record but didn't find it to be already indexed.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Modify</term>
+ <listitem>
+ <para>
+ The record has already been indexed.
+ In this case either the contents of the record or the location
+ (file) of the record indicates that it has been indexed before.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Delete</term>
+ <listitem>
+ <para>
+ The record is deleted from the index. As in the
+ update-case it must be able to identify the record.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+
+ <para>
+ Please note that in both the modify- and delete- case the &zebra;
+ indexer must be able to generate a unique key that identifies the record
+ in question (more on this below).
+ </para>
+
+ <para>
+ To administrate the &zebra; retrieval system, you run the
+ <literal>zebraidx</literal> program.
+ This program supports a number of options which are preceded by a dash,
+ and a few commands (not preceded by dash).
+</para>
+
+ <para>
+ Both the &zebra; administrative tool and the &acro.z3950; server share a
+ set of index files and a global configuration file.
+ The name of the configuration file defaults to
+ <literal>zebra.cfg</literal>.
+ The configuration file includes specifications on how to index
+ various kinds of records and where the other configuration files
+ are located. <literal>zebrasrv</literal> and <literal>zebraidx</literal>
+ <emphasis>must</emphasis> be run in the directory where the
+ configuration file lives unless you indicate the location of the
+ configuration file by option <literal>-c</literal>.
+ </para>
+
+ <sect1 id="record-types">
+ <title>Record Types</title>
+
+ <para>
+ Indexing is a per-record process, in which either insert/modify/delete
+ will occur. Before a record is indexed search keys are extracted from
+ whatever might be the layout the original record (sgml,html,text, etc..).
+ The &zebra; system currently supports two fundamental types of records:
+ structured and simple text.
+ To specify a particular extraction process, use either the
+ command line option <literal>-t</literal> or specify a
+ <literal>recordType</literal> setting in the configuration file.
+ </para>
+
+ </sect1>
+
+ <sect1 id="zebra-cfg">
+ <title>The &zebra; Configuration File</title>
+
+ <para>
+ The &zebra; configuration file, read by <literal>zebraidx</literal> and
+ <literal>zebrasrv</literal> defaults to <literal>zebra.cfg</literal>
+ unless specified by <literal>-c</literal> option.
+ </para>
+
+ <para>
+ You can edit the configuration file with a normal text editor.
+ parameter names and values are separated by colons in the file. Lines
+ starting with a hash sign (<literal>#</literal>) are
+ treated as comments.
+ </para>
+
+ <para>
+ If you manage different sets of records that share common
+ characteristics, you can organize the configuration settings for each
+ type into "groups".
+ When <literal>zebraidx</literal> is run and you wish to address a
+ given group you specify the group name with the <literal>-g</literal>
+ option.
+ In this case settings that have the group name as their prefix
+ will be used by <literal>zebraidx</literal>.
+ If no <literal>-g</literal> option is specified, the settings
+ without prefix are used.
+ </para>
+
+ <para>
+ In the configuration file, the group name is placed before the option
+ name itself, separated by a dot (.). For instance, to set the record type
+ for group <literal>public</literal> to <literal>grs.sgml</literal>
+ (the &acro.sgml;-like format for structured records) you would write:
+ </para>
+
+ <para>
+ <screen>
+ public.recordType: grs.sgml
+ </screen>
+ </para>
+
+ <para>
+ To set the default value of the record type to <literal>text</literal>
+ write:
+ </para>
+
+ <para>
+ <screen>
+ recordType: text
+ </screen>
+ </para>
+
+ <para>
+ The available configuration settings are summarized below. They will be
+ explained further in the following sections.
+ </para>
+
+ <!--
+ FIXME - Didn't Adam make something to have multiple databases in multiple dirs...
+ -->
+
+ <para>
+ <variablelist>
+
+ <varlistentry>
+ <term>
+ <emphasis>group</emphasis>
+ .recordType[<emphasis>.name</emphasis>]:
+ <replaceable>type</replaceable>
+ </term>
+ <listitem>
+ <para>
+ Specifies how records with the file extension
+ <emphasis>name</emphasis> should be handled by the indexer.
+ This option may also be specified as a command line option
+ (<literal>-t</literal>). Note that if you do not specify a
+ <emphasis>name</emphasis>, the setting applies to all files.
+ In general, the record type specifier consists of the elements (each
+ element separated by dot), <emphasis>fundamental-type</emphasis>,
+ <emphasis>file-read-type</emphasis> and arguments. Currently, two
+ fundamental types exist, <literal>text</literal> and
+ <literal>grs</literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><emphasis>group</emphasis>.recordId:
+ <replaceable>record-id-spec</replaceable></term>
+ <listitem>
+ <para>
+ Specifies how the records are to be identified when updated. See
+ <xref linkend="locating-records"/>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><emphasis>group</emphasis>.database:
+ <replaceable>database</replaceable></term>
+ <listitem>
+ <para>
+ Specifies the &acro.z3950; database name.
+ <!-- FIXME - now we can have multiple databases in one server. -H -->
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><emphasis>group</emphasis>.storeKeys:
+ <replaceable>boolean</replaceable></term>
+ <listitem>
+ <para>
+ Specifies whether key information should be saved for a given
+ group of records. If you plan to update/delete this type of
+ records later this should be specified as 1; otherwise it
+ should be 0 (default), to save register space.
+ <!-- ### this is the first mention of "register" -->
+ See <xref linkend="file-ids"/>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><emphasis>group</emphasis>.storeData:
+ <replaceable>boolean</replaceable></term>
+ <listitem>
+ <para>
+ Specifies whether the records should be stored internally
+ in the &zebra; system files.
+ If you want to maintain the raw records yourself,
+ this option should be false (0).
+ If you want &zebra; to take care of the records for you, it
+ should be true(1).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <!-- ### probably a better place to define "register" -->
+ <term>register: <replaceable>register-location</replaceable></term>
+ <listitem>
+ <para>
+ Specifies the location of the various register files that &zebra; uses
+ to represent your databases.
+ See <xref linkend="register-location"/>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>shadow: <replaceable>register-location</replaceable></term>
+ <listitem>
+ <para>
+ Enables the <emphasis>safe update</emphasis> facility of &zebra;, and
+ tells the system where to place the required, temporary files.
+ See <xref linkend="shadow-registers"/>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>lockDir: <replaceable>directory</replaceable></term>
+ <listitem>
+ <para>
+ Directory in which various lock files are stored.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>keyTmpDir: <replaceable>directory</replaceable></term>
+ <listitem>
+ <para>
+ Directory in which temporary files used during zebraidx's update
+ phase are stored.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>setTmpDir: <replaceable>directory</replaceable></term>
+ <listitem>
+ <para>
+ Specifies the directory that the server uses for temporary result sets.
+ If not specified <literal>/tmp</literal> will be used.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>profilePath: <replaceable>path</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a path of profile specification files.
+ The path is composed of one or more directories separated by
+ colon. Similar to <literal>PATH</literal> for UNIX systems.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>modulePath: <replaceable>path</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a path of record filter modules.
+ The path is composed of one or more directories separated by
+ colon. Similar to <literal>PATH</literal> for UNIX systems.
+ The 'make install' procedure typically puts modules in
+ <filename>/usr/local/lib/idzebra-2.0/modules</filename>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>index: <replaceable>filename</replaceable></term>
+ <listitem>
+ <para>
+ Defines the filename which holds fields structure
+ definitions. If omitted, the file <filename>default.idx</filename>
+ is read.
+ Refer to <xref linkend="default-idx-file"/> for
+ more information.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>sortmax: <replaceable>integer</replaceable></term>
+ <listitem>
+ <para>
+ Specifies the maximum number of records that will be sorted
+ in a result set. If the result set contains more than
+ <replaceable>integer</replaceable> records, records after the
+ limit will not be sorted. If omitted, the default value is
+ 1,000.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>staticrank: <replaceable>integer</replaceable></term>
+ <listitem>
+ <para>
+ Enables whether static ranking is to be enabled (1) or
+ disabled (0). If omitted, it is disabled - corresponding
+ to a value of 0.
+ Refer to <xref linkend="administration-ranking-static"/> .
+ </para>
+ </listitem>
+ </varlistentry>
+
+
+ <varlistentry>
+ <term>estimatehits: <replaceable>integer</replaceable></term>
+ <listitem>
+ <para>
+ Controls whether &zebra; should calculate approximate hit counts and
+ at which hit count it is to be enabled.
+ A value of 0 disables approximate hit counts.
+ For a positive value approximate hit count is enabled
+ if it is known to be larger than <replaceable>integer</replaceable>.
+ </para>
+ <para>
+ Approximate hit counts can also be triggered by a particular
+ attribute in a query.
+ Refer to <xref linkend="querymodel-zebra-global-attr-limit"/>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>attset: <replaceable>filename</replaceable></term>
+ <listitem>
+ <para>
+ Specifies the filename(s) of attribute set files for use in
+ searching. In many configurations <filename>bib1.att</filename>
+ is used, but that is not required. If Classic Explain
+ attributes is to be used for searching,
+ <filename>explain.att</filename> must be given.
+ The path to att-files in general can be given using
+ <literal>profilePath</literal> setting.
+ See also <xref linkend="attset-files"/>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>memMax: <replaceable>size</replaceable></term>
+ <listitem>
+ <para>
+ Specifies <replaceable>size</replaceable> of internal memory
+ to use for the zebraidx program.
+ The amount is given in megabytes - default is 4 (4 MB).
+ The more memory, the faster large updates happen, up to about
+ half the free memory available on the computer.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>tempfiles: <replaceable>Yes/Auto/No</replaceable></term>
+ <listitem>
+ <para>
+ Tells zebra if it should use temporary files when indexing. The
+ default is Auto, in which case zebra uses temporary files only
+ if it would need more that <replaceable>memMax</replaceable>
+ megabytes of memory. This should be good for most uses.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>root: <replaceable>dir</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a directory base for &zebra;. All relative paths
+ given (in profilePath, register, shadow) are based on this
+ directory. This setting is useful if your &zebra; server
+ is running in a different directory from where
+ <literal>zebra.cfg</literal> is located.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>passwd: <replaceable>file</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a file with description of user accounts for &zebra;.
+ The format is similar to that known to Apache's htpasswd files
+ and UNIX' passwd files. Non-empty lines not beginning with
+ # are considered account lines. There is one account per-line.
+ A line consists of fields separate by a single colon character.
+ First field is username, second is password.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>passwd.c: <replaceable>file</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a file with description of user accounts for &zebra;.
+ File format is similar to that used by the passwd directive except
+ that the password are encrypted. Use Apache's htpasswd or similar
+ for maintenance.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>perm.<replaceable>user</replaceable>:
+ <replaceable>permstring</replaceable></term>
+ <listitem>
+ <para>
+ Specifies permissions (privilege) for a user that are allowed
+ to access &zebra; via the passwd system. There are two kinds
+ of permissions currently: read (r) and write(w). By default
+ users not listed in a permission directive are given the read
+ privilege. To specify permissions for a user with no
+ username, or &acro.z3950; anonymous style use
+ <literal>anonymous</literal>. The permstring consists of
+ a sequence of characters. Include character <literal>w</literal>
+ for write/update access, <literal>r</literal> for read access and
+ <literal>a</literal> to allow anonymous access through this account.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>dbaccess: <replaceable>accessfile</replaceable></term>
+ <listitem>
+ <para>
+ Names a file which lists database subscriptions for individual users.
+ The access file should consists of lines of the form
+ <literal>username: dbnames</literal>, where dbnames is a list of
+ database names, separated by '+'. No whitespace is allowed in the
+ database list.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>encoding: <replaceable>charsetname</replaceable></term>
+ <listitem>
+ <para>
+ Tells &zebra; to interpret the terms in Z39.50 queries as
+ having been encoded using the specified character
+ encoding. The default is <literal>ISO-8859-1</literal>; one
+ useful alternative is <literal>UTF-8</literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>storeKeys: <replaceable>value</replaceable></term>
+ <listitem>
+ <para>
+ Specifies whether &zebra; keeps a copy of indexed keys.
+ Use a value of 1 to enable; 0 to disable. If storeKeys setting is
+ omitted, it is enabled. Enabled storeKeys
+ are required for updating and deleting records. Disable only
+ storeKeys to save space and only plan to index data once.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>storeData: <replaceable>value</replaceable></term>
+ <listitem>
+ <para>
+ Specifies whether &zebra; keeps a copy of indexed records.
+ Use a value of 1 to enable; 0 to disable. If storeData setting is
+ omitted, it is enabled. A storeData setting of 0 (disabled) makes
+ Zebra fetch records from the original locaction in the file
+ system using filename, file offset and file length. For the
+ DOM and ALVIS filter, the storeData setting is ignored.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ </variablelist>
+ </para>
+
+ </sect1>
+
+ <sect1 id="locating-records">
+ <title>Locating Records</title>
+
+ <para>
+ The default behavior of the &zebra; system is to reference the
+ records from their original location, i.e. where they were found when you
+ run <literal>zebraidx</literal>.
+ That is, when a client wishes to retrieve a record
+ following a search operation, the files are accessed from the place
+ where you originally put them - if you remove the files (without
+ running <literal>zebraidx</literal> again, the server will return
+ diagnostic number 14 (``System error in presenting records'') to
+ the client.
+ </para>
+
+ <para>
+ If your input files are not permanent - for example if you retrieve
+ your records from an outside source, or if they were temporarily
+ mounted on a CD-ROM drive,
+ you may want &zebra; to make an internal copy of them. To do this,
+ you specify 1 (true) in the <literal>storeData</literal> setting. When
+ the &acro.z3950; server retrieves the records they will be read from the
+ internal file structures of the system.
+ </para>
+
+ </sect1>
+
+ <sect1 id="simple-indexing">
+ <title>Indexing with no Record IDs (Simple Indexing)</title>
+
+ <para>
+ If you have a set of records that are not expected to change over time
+ you may can build your database without record IDs.
+ This indexing method uses less space than the other methods and
+ is simple to use.
+ </para>
+
+ <para>
+ To use this method, you simply omit the <literal>recordId</literal> entry
+ for the group of files that you index. To add a set of records you use
+ <literal>zebraidx</literal> with the <literal>update</literal> command. The
+ <literal>update</literal> command will always add all of the records that it
+ encounters to the index - whether they have already been indexed or
+ not. If the set of indexed files change, you should delete all of the
+ index files, and build a new index from scratch.
+ </para>
+
+ <para>
+ Consider a system in which you have a group of text files called
+ <literal>simple</literal>.
+ That group of records should belong to a &acro.z3950; database called
+ <literal>textbase</literal>.
+ The following <literal>zebra.cfg</literal> file will suffice:
+ </para>
+ <para>
+
+ <screen>
+ profilePath: /usr/local/idzebra/tab
+ attset: bib1.att
+ simple.recordType: text
+ simple.database: textbase
+ </screen>
+
+ </para>
+
+ <para>
+ Since the existing records in an index can not be addressed by their
+ IDs, it is impossible to delete or modify records when using this method.
+ </para>
+
+ </sect1>
+
+ <sect1 id="file-ids">
+ <title>Indexing with File Record IDs</title>
+
+ <para>
+ If you have a set of files that regularly change over time: Old files
+ are deleted, new ones are added, or existing files are modified, you
+ can benefit from using the <emphasis>file ID</emphasis>
+ indexing methodology.
+ Examples of this type of database might include an index of WWW
+ resources, or a USENET news spool area.
+ Briefly speaking, the file key methodology uses the directory paths
+ of the individual records as a unique identifier for each record.
+ To perform indexing of a directory with file keys, again, you specify
+ the top-level directory after the <literal>update</literal> command.
+ The command will recursively traverse the directories and compare
+ each one with whatever have been indexed before in that same directory.
+ If a file is new (not in the previous version of the directory) it
+ is inserted into the registers; if a file was already indexed and
+ it has been modified since the last update, the index is also
+ modified; if a file has been removed since the last
+ visit, it is deleted from the index.
+ </para>
+
+ <para>
+ The resulting system is easy to administrate. To delete a record you
+ simply have to delete the corresponding file (say, with the
+ <literal>rm</literal> command). And to add records you create new
+ files (or directories with files). For your changes to take effect
+ in the register you must run <literal>zebraidx update</literal> with
+ the same directory root again. This mode of operation requires more
+ disk space than simpler indexing methods, but it makes it easier for
+ you to keep the index in sync with a frequently changing set of data.
+ If you combine this system with the <emphasis>safe update</emphasis>
+ facility (see below), you never have to take your server off-line for
+ maintenance or register updating purposes.
+ </para>
+
+ <para>
+ To enable indexing with pathname IDs, you must specify
+ <literal>file</literal> as the value of <literal>recordId</literal>
+ in the configuration file. In addition, you should set
+ <literal>storeKeys</literal> to <literal>1</literal>, since the &zebra;
+ indexer must save additional information about the contents of each record
+ in order to modify the indexes correctly at a later time.
+ </para>
+
+ <!--
+ FIXME - There must be a simpler way to do this with Adams string tags -H
+ -->
+
+ <para>
+ For example, to update records of group <literal>esdd</literal>
+ located below
+ <literal>/data1/records/</literal> you should type:
+ <screen>
+ $ zebraidx -g esdd update /data1/records
+ </screen>
+ </para>
+
+ <para>
+ The corresponding configuration file includes:
+ <screen>
+ esdd.recordId: file
+ esdd.recordType: grs.sgml
+ esdd.storeKeys: 1
+ </screen>
+ </para>
+
+ <note>
+ <para>You cannot start out with a group of records with simple
+ indexing (no record IDs as in the previous section) and then later
+ enable file record Ids. &zebra; must know from the first time that you
+ index the group that
+ the files should be indexed with file record IDs.
+ </para>
+ </note>
+
+ <para>
+ You cannot explicitly delete records when using this method (using the
+ <literal>delete</literal> command to <literal>zebraidx</literal>. Instead
+ you have to delete the files from the file system (or move them to a
+ different location)
+ and then run <literal>zebraidx</literal> with the
+ <literal>update</literal> command.
+ </para>
+ <!-- ### what happens if a file contains multiple records? -->
</sect1>
+
+ <sect1 id="generic-ids">
+ <title>Indexing with General Record IDs</title>
+
+ <para>
+ When using this method you construct an (almost) arbitrary, internal
+ record key based on the contents of the record itself and other system
+ information. If you have a group of records that explicitly associates
+ an ID with each record, this method is convenient. For example, the
+ record format may contain a title or a ID-number - unique within the group.
+ In either case you specify the &acro.z3950; attribute set and use-attribute
+ location in which this information is stored, and the system looks at
+ that field to determine the identity of the record.
+ </para>
+
+ <para>
+ As before, the record ID is defined by the <literal>recordId</literal>
+ setting in the configuration file. The value of the record ID specification
+ consists of one or more tokens separated by whitespace. The resulting
+ ID is represented in the index by concatenating the tokens and
+ separating them by ASCII value (1).
+ </para>
+
+ <para>
+ There are three kinds of tokens:
+ <variablelist>
+
+ <varlistentry>
+ <term>Internal record info</term>
+ <listitem>
+ <para>
+ The token refers to a key that is
+ extracted from the record. The syntax of this token is
+ <literal>(</literal> <emphasis>set</emphasis> <literal>,</literal>
+ <emphasis>use</emphasis> <literal>)</literal>,
+ where <emphasis>set</emphasis> is the
+ attribute set name <emphasis>use</emphasis> is the
+ name or value of the attribute.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>System variable</term>
+ <listitem>
+ <para>
+ The system variables are preceded by
+
+ <screen>
+ $
+ </screen>
+ and immediately followed by the system variable name, which
+ may one of
+ <variablelist>
+
+ <varlistentry>
+ <term>group</term>
+ <listitem>
+ <para>
+ Group name.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>database</term>
+ <listitem>
+ <para>
+ Current database specified.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>type</term>
+ <listitem>
+ <para>
+ Record type.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Constant string</term>
+ <listitem>
+ <para>
+ A string used as part of the ID — surrounded
+ by single- or double quotes.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+
+ <para>
+ For instance, the sample GILS records that come with the &zebra;
+ distribution contain a unique ID in the data tagged Control-Identifier.
+ The data is mapped to the &acro.bib1; use attribute Identifier-standard
+ (code 1007). To use this field as a record id, specify
+ <literal>(bib1,Identifier-standard)</literal> as the value of the
+ <literal>recordId</literal> in the configuration file.
+ If you have other record types that uses the same field for a
+ different purpose, you might add the record type
+ (or group or database name) to the record id of the gils
+ records as well, to prevent matches with other types of records.
+ In this case the recordId might be set like this:
+
+ <screen>
+ gils.recordId: $type (bib1,Identifier-standard)
+ </screen>
+
+ </para>
+
+ <para>
+ (see <xref linkend="grs"/>
+ for details of how the mapping between elements of your records and
+ searchable attributes is established).
+ </para>
+
+ <para>
+ As for the file record ID case described in the previous section,
+ updating your system is simply a matter of running
+ <literal>zebraidx</literal>
+ with the <literal>update</literal> command. However, the update with general
+ keys is considerably slower than with file record IDs, since all files
+ visited must be (re)read to discover their IDs.
+ </para>
+
+ <para>
+ As you might expect, when using the general record IDs
+ method, you can only add or modify existing records with the
+ <literal>update</literal> command.
+ If you wish to delete records, you must use the,
+ <literal>delete</literal> command, with a directory as a parameter.
+ This will remove all records that match the files below that root
+ directory.
+ </para>
+
+ </sect1>
+
+ <sect1 id="register-location">
+ <title>Register Location</title>
+
+ <para>
+ Normally, the index files that form dictionaries, inverted
+ files, record info, etc., are stored in the directory where you run
+ <literal>zebraidx</literal>. If you wish to store these, possibly large,
+ files somewhere else, you must add the <literal>register</literal>
+ entry to the <literal>zebra.cfg</literal> file.
+ Furthermore, the &zebra; system allows its file
+ structures to span multiple file systems, which is useful for
+ managing very large databases.
+ </para>
+
+ <para>
+ The value of the <literal>register</literal> setting is a sequence
+ of tokens. Each token takes the form:
+
+ <emphasis>dir</emphasis><literal>:</literal><emphasis>size</emphasis>
+
+ The <emphasis>dir</emphasis> specifies a directory in which index files
+ will be stored and the <emphasis>size</emphasis> specifies the maximum
+ size of all files in that directory. The &zebra; indexer system fills
+ each directory in the order specified and use the next specified
+ directories as needed.
+ The <emphasis>size</emphasis> is an integer followed by a qualifier
+ code,
+ <literal>b</literal> for bytes,
+ <literal>k</literal> for kilobytes.
+ <literal>M</literal> for megabytes,
+ <literal>G</literal> for gigabytes.
+ Specifying a negative value disables the checking (it still needs the unit,
+ use <literal>-1b</literal>).
+ </para>
+
+ <para>
+ For instance, if you have allocated three disks for your register, and
+ the first disk is mounted
+ on <literal>/d1</literal> and has 2GB of free space, the
+ second, mounted on <literal>/d2</literal> has 3.6 GB, and the third,
+ on which you have more space than you bother to worry about, mounted on
+ <literal>/d3</literal> you could put this entry in your configuration file:
+
+ <screen>
+ register: /d1:2G /d2:3600M /d3:-1b
+ </screen>
+ </para>
+
+ <para>
+ Note that &zebra; does not verify that the amount of space specified is
+ actually available on the directory (file system) specified - it is
+ your responsibility to ensure that enough space is available, and that
+ other applications do not attempt to use the free space. In a large
+ production system, it is recommended that you allocate one or more
+ file system exclusively to the &zebra; register files.
+ </para>
+
+ </sect1>
+
+ <sect1 id="shadow-registers">
+ <title>Safe Updating - Using Shadow Registers</title>
+
+ <sect2 id="shadow-registers-description">
+ <title>Description</title>
+
+ <para>
+ The &zebra; server supports <emphasis>updating</emphasis> of the index
+ structures. That is, you can add, modify, or remove records from
+ databases managed by &zebra; without rebuilding the entire index.
+ Since this process involves modifying structured files with various
+ references between blocks of data in the files, the update process
+ is inherently sensitive to system crashes, or to process interruptions:
+ Anything but a successfully completed update process will leave the
+ register files in an unknown state, and you will essentially have no
+ recourse but to re-index everything, or to restore the register files
+ from a backup medium.
+ Further, while the update process is active, users cannot be
+ allowed to access the system, as the contents of the register files
+ may change unpredictably.
+ </para>
+
+ <para>
+ You can solve these problems by enabling the shadow register system in
+ &zebra;.
+ During the updating procedure, <literal>zebraidx</literal> will temporarily
+ write changes to the involved files in a set of "shadow
+ files", without modifying the files that are accessed by the
+ active server processes. If the update procedure is interrupted by a
+ system crash or a signal, you simply repeat the procedure - the
+ register files have not been changed or damaged, and the partially
+ written shadow files are automatically deleted before the new updating
+ procedure commences.
+ </para>
+
+ <para>
+ At the end of the updating procedure (or in a separate operation, if
+ you so desire), the system enters a "commit mode". First,
+ any active server processes are forced to access those blocks that
+ have been changed from the shadow files rather than from the main
+ register files; the unmodified blocks are still accessed at their
+ normal location (the shadow files are not a complete copy of the
+ register files - they only contain those parts that have actually been
+ modified). If the commit process is interrupted at any point during the
+ commit process, the server processes will continue to access the
+ shadow files until you can repeat the commit procedure and complete
+ the writing of data to the main register files. You can perform
+ multiple update operations to the registers before you commit the
+ changes to the system files, or you can execute the commit operation
+ at the end of each update operation. When the commit phase has
+ completed successfully, any running server processes are instructed to
+ switch their operations to the new, operational register, and the
+ temporary shadow files are deleted.
+ </para>
+
+ </sect2>
+
+ <sect2 id="shadow-registers-how-to-use">
+ <title>How to Use Shadow Register Files</title>
+
+ <para>
+ The first step is to allocate space on your system for the shadow
+ files.
+ You do this by adding a <literal>shadow</literal> entry to the
+ <literal>zebra.cfg</literal> file.
+ The syntax of the <literal>shadow</literal> entry is exactly the
+ same as for the <literal>register</literal> entry
+ (see <xref linkend="register-location"/>).
+ The location of the shadow area should be
+ <emphasis>different</emphasis> from the location of the main register
+ area (if you have specified one - remember that if you provide no
+ <literal>register</literal> setting, the default register area is the
+ working directory of the server and indexing processes).
+ </para>
+
+ <para>
+ The following excerpt from a <literal>zebra.cfg</literal> file shows
+ one example of a setup that configures both the main register
+ location and the shadow file area.
+ Note that two directories or partitions have been set aside
+ for the shadow file area. You can specify any number of directories
+ for each of the file areas, but remember that there should be no
+ overlaps between the directories used for the main registers and the
+ shadow files, respectively.
+ </para>
+ <para>
+
+ <screen>
+ register: /d1:500M
+ shadow: /scratch1:100M /scratch2:200M
+ </screen>
+
+ </para>
+
+ <para>
+ When shadow files are enabled, an extra command is available at the
+ <literal>zebraidx</literal> command line.
+ In order to make changes to the system take effect for the
+ users, you'll have to submit a "commit" command after a
+ (sequence of) update operation(s).
+ </para>
+
+ <para>
+
+ <screen>
+ $ zebraidx update /d1/records
+ $ zebraidx commit
+ </screen>
+
+ </para>
+
+ <para>
+ Or you can execute multiple updates before committing the changes:
+ </para>
+
+ <para>
+
+ <screen>
+ $ zebraidx -g books update /d1/records /d2/more-records
+ $ zebraidx -g fun update /d3/fun-records
+ $ zebraidx commit
+ </screen>
+
+ </para>
+
+ <para>
+ If one of the update operations above had been interrupted, the commit
+ operation on the last line would fail: <literal>zebraidx</literal>
+ will not let you commit changes that would destroy the running register.
+ You'll have to rerun all of the update operations since your last
+ commit operation, before you can commit the new changes.
+ </para>
+
+ <para>
+ Similarly, if the commit operation fails, <literal>zebraidx</literal>
+ will not let you start a new update operation before you have
+ successfully repeated the commit operation.
+ The server processes will keep accessing the shadow files rather
+ than the (possibly damaged) blocks of the main register files
+ until the commit operation has successfully completed.
+ </para>
+
+ <para>
+ You should be aware that update operations may take slightly longer
+ when the shadow register system is enabled, since more file access
+ operations are involved. Further, while the disk space required for
+ the shadow register data is modest for a small update operation, you
+ may prefer to disable the system if you are adding a very large number
+ of records to an already very large database (we use the terms
+ <emphasis>large</emphasis> and <emphasis>modest</emphasis>
+ very loosely here, since every application will have a
+ different perception of size).
+ To update the system without the use of the the shadow files,
+ simply run <literal>zebraidx</literal> with the <literal>-n</literal>
+ option (note that you do not have to execute the
+ <emphasis>commit</emphasis> command of <literal>zebraidx</literal>
+ when you temporarily disable the use of the shadow registers in
+ this fashion.
+ Note also that, just as when the shadow registers are not enabled,
+ server processes will be barred from accessing the main register
+ while the update procedure takes place.
+ </para>
+
+ </sect2>
+
+ </sect1>
+
+
+ <sect1 id="administration-ranking">
+ <title>Relevance Ranking and Sorting of Result Sets</title>
+
+ <sect2 id="administration-overview">
+ <title>Overview</title>
+ <para>
+ The default ordering of a result set is left up to the server,
+ which inside &zebra; means sorting in ascending document ID order.
+ This is not always the order humans want to browse the sometimes
+ quite large hit sets. Ranking and sorting comes to the rescue.
+ </para>
+
+ <para>
+ In cases where a good presentation ordering can be computed at
+ indexing time, we can use a fixed <literal>static ranking</literal>
+ scheme, which is provided for the <literal>alvis</literal>
+ indexing filter. This defines a fixed ordering of hit lists,
+ independently of the query issued.
+ </para>
+
+ <para>
+ There are cases, however, where relevance of hit set documents is
+ highly dependent on the query processed.
+ Simply put, <literal>dynamic relevance ranking</literal>
+ sorts a set of retrieved records such that those most likely to be
+ relevant to your request are retrieved first.
+ Internally, &zebra; retrieves all documents that satisfy your
+ query, and re-orders the hit list to arrange them based on
+ a measurement of similarity between your query and the content of
+ each record.
+ </para>
+
+ <para>
+ Finally, there are situations where hit sets of documents should be
+ <literal>sorted</literal> during query time according to the
+ lexicographical ordering of certain sort indexes created at
+ indexing time.
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-ranking-static">
+ <title>Static Ranking</title>
+
+ <para>
+ &zebra; uses internally inverted indexes to look up term frequencies
+ in documents. Multiple queries from different indexes can be
+ combined by the binary boolean operations <literal>AND</literal>,
+ <literal>OR</literal> and/or <literal>NOT</literal> (which
+ is in fact a binary <literal>AND NOT</literal> operation).
+ To ensure fast query execution
+ speed, all indexes have to be sorted in the same order.
+ </para>
+ <para>
+ The indexes are normally sorted according to document
+ <literal>ID</literal> in
+ ascending order, and any query which does not invoke a special
+ re-ranking function will therefore retrieve the result set in
+ document
+ <literal>ID</literal>
+ order.
+ </para>
+ <para>
+ If one defines the
+ <screen>
+ staticrank: 1
+ </screen>
+ directive in the main core &zebra; configuration file, the internal document
+ keys used for ordering are augmented by a preceding integer, which
+ contains the static rank of a given document, and the index lists
+ are ordered
+ first by ascending static rank,
+ then by ascending document <literal>ID</literal>.
+ Zero
+ is the ``best'' rank, as it occurs at the
+ beginning of the list; higher numbers represent worse scores.
+ </para>
+ <para>
+ The experimental <literal>alvis</literal> filter provides a
+ directive to fetch static rank information out of the indexed &acro.xml;
+ records, thus making <emphasis>all</emphasis> hit sets ordered
+ after <emphasis>ascending</emphasis> static
+ rank, and for those doc's which have the same static rank, ordered
+ after <emphasis>ascending</emphasis> doc <literal>ID</literal>.
+ See <xref linkend="record-model-alvisxslt"/> for the gory details.
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-ranking-dynamic">
+ <title>Dynamic Ranking</title>
+ <para>
+ In order to fiddle with the static rank order, it is necessary to
+ invoke additional re-ranking/re-ordering using dynamic
+ ranking or score functions. These functions return positive
+ integer scores, where <emphasis>highest</emphasis> score is
+ ``best'';
+ hit sets are sorted according to <emphasis>descending</emphasis>
+ scores (in contrary
+ to the index lists which are sorted according to
+ ascending rank number and document ID).
+ </para>
+ <para>
+ Dynamic ranking is enabled by a directive like one of the
+ following in the zebra configuration file (use only one of these a time!):
+ <screen>
+ rank: rank-1 # default TDF-IDF like
+ rank: rank-static # dummy do-nothing
+ </screen>
+ </para>
+
+ <para>
+ Dynamic ranking is done at query time rather than
+ indexing time (this is why we
+ call it ``dynamic ranking'' in the first place ...)
+ It is invoked by adding
+ the &acro.bib1; relation attribute with
+ value ``relevance'' to the &acro.pqf; query (that is,
+ <literal>@attr 2=102</literal>, see also
+ <ulink url="&url.z39.50;bib1.html">
+ The &acro.bib1; Attribute Set Semantics</ulink>, also in
+ <ulink url="&url.z39.50.attset.bib1;">HTML</ulink>).
+ To find all articles with the word <literal>Eoraptor</literal> in
+ the title, and present them relevance ranked, issue the &acro.pqf; query:
+ <screen>
+ @attr 2=102 @attr 1=4 Eoraptor
+ </screen>
+ </para>
+
+ <sect3 id="administration-ranking-dynamic-rank1">
+ <title>Dynamically ranking using &acro.pqf; queries with the 'rank-1'
+ algorithm</title>
+
+ <para>
+ The default <literal>rank-1</literal> ranking module implements a
+ TF/IDF (Term Frequecy over Inverse Document Frequency) like
+ algorithm. In contrast to the usual definition of TF/IDF
+ algorithms, which only considers searching in one full-text
+ index, this one works on multiple indexes at the same time.
+ More precisely,
+ &zebra; does boolean queries and searches in specific addressed
+ indexes (there are inverted indexes pointing from terms in the
+ dictionary to documents and term positions inside documents).
+ It works like this:
+ <variablelist>
+ <varlistentry>
+ <term>Query Components</term>
+ <listitem>
+ <para>
+ First, the boolean query is dismantled into its principal components,
+ i.e. atomic queries where one term is looked up in one index.
+ For example, the query
+ <screen>
+ @attr 2=102 @and @attr 1=1010 Utah @attr 1=1018 Springer
+ </screen>
+ is a boolean AND between the atomic parts
+ <screen>
+ @attr 2=102 @attr 1=1010 Utah
+ </screen>
+ and
+ <screen>
+ @attr 2=102 @attr 1=1018 Springer
+ </screen>
+ which gets processed each for itself.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Atomic hit lists</term>
+ <listitem>
+ <para>
+ Second, for each atomic query, the hit list of documents is
+ computed.
+ </para>
+ <para>
+ In this example, two hit lists for each index
+ <literal>@attr 1=1010</literal> and
+ <literal>@attr 1=1018</literal> are computed.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Atomic scores</term>
+ <listitem>
+ <para>
+ Third, each document in the hit list is assigned a score (_if_ ranking
+ is enabled and requested in the query) using a TF/IDF scheme.
+ </para>
+ <para>
+ In this example, both atomic parts of the query assign the magic
+ <literal>@attr 2=102</literal> relevance attribute, and are
+ to be used in the relevance ranking functions.
+ </para>
+ <para>
+ It is possible to apply dynamic ranking on only parts of the
+ &acro.pqf; query:
+ <screen>
+ @and @attr 2=102 @attr 1=1010 Utah @attr 1=1018 Springer
+ </screen>
+ searches for all documents which have the term 'Utah' on the
+ body of text, and which have the term 'Springer' in the publisher
+ field, and sort them in the order of the relevance ranking made on
+ the body-of-text index only.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Hit list merging</term>
+ <listitem>
+ <para>
+ Fourth, the atomic hit lists are merged according to the boolean
+ conditions to a final hit list of documents to be returned.
+ </para>
+ <para>
+ This step is always performed, independently of the fact that
+ dynamic ranking is enabled or not.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Document score computation</term>
+ <listitem>
+ <para>
+ Fifth, the total score of a document is computed as a linear
+ combination of the atomic scores of the atomic hit lists
+ </para>
+ <para>
+ Ranking weights may be used to pass a value to a ranking
+ algorithm, using the non-standard &acro.bib1; attribute type 9.
+ This allows one branch of a query to use one value while
+ another branch uses a different one. For example, we can search
+ for <literal>utah</literal> in the
+ <literal>@attr 1=4</literal> index with weight 30, as
+ well as in the <literal>@attr 1=1010</literal> index with weight 20:
+ <screen>
+ @attr 2=102 @or @attr 9=30 @attr 1=4 utah @attr 9=20 @attr 1=1010 city
+ </screen>
+ </para>
+ <para>
+ The default weight is
+ sqrt(1000) ~ 34 , as the &acro.z3950; standard prescribes that the top score
+ is 1000 and the bottom score is 0, encoded in integers.
+ </para>
+ <warning>
+ <para>
+ The ranking-weight feature is experimental. It may change in future
+ releases of zebra.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Re-sorting of hit list</term>
+ <listitem>
+ <para>
+ Finally, the final hit list is re-ordered according to scores.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+
+<!--
+Still need to describe the exact TF/IDF formula. Here's the info, need -->
+<!--to extract it in human readable form .. MC
+
+static int calc (void *set_handle, zint sysno, zint staticrank,
+ int *stop_flag)
+{
+ int i, lo, divisor, score = 0;
+ struct rank_set_info *si = (struct rank_set_info *) set_handle;
+
+ if (!si->no_rank_entries)
+ return -1; /* ranking not enabled for any terms */
+
+ for (i = 0; i < si->no_entries; i++)
+ {
+ yaz_log(log_level, "calc: i=%d rank_flag=%d lo=%d",
+ i, si->entries[i].rank_flag, si->entries[i].local_occur);
+ if (si->entries[i].rank_flag && (lo = si->entries[i].local_occur))
+ score += (8+log2_int (lo)) * si->entries[i].global_inv *
+ si->entries[i].rank_weight;
+ }
+ divisor = si->no_rank_entries * (8+log2_int (si->last_pos/si->no_entries));
+ score = score / divisor;
+ yaz_log(log_level, "calc sysno=" ZINT_FORMAT " score=%d", sysno, score);
+ if (score > 1000)
+ score = 1000;
+ /* reset the counts for the next term */
+ for (i = 0; i < si->no_entries; i++)
+ si->entries[i].local_occur = 0;
+ return score;
+}
+
+
+where lo = si->entries[i].local_occur is the local documents term-within-index frequency, si->entries[i].global_inv represents the IDF part (computed in static void *begin()), and
+si->entries[i].rank_weight is the weight assigner per index (default 34, or set in the @attr 9=xyz magic)
+
+Finally, the IDF part is computed as:
+
+static void *begin (struct zebra_register *reg,
+ void *class_handle, RSET rset, NMEM nmem,
+ TERMID *terms, int numterms)
+{
+ struct rank_set_info *si =
+ (struct rank_set_info *) nmem_malloc (nmem,sizeof(*si));
+ int i;
+
+ yaz_log(log_level, "rank-1 begin");
+ si->no_entries = numterms;
+ si->no_rank_entries = 0;
+ si->nmem=nmem;
+ si->entries = (struct rank_term_info *)
+ nmem_malloc (si->nmem, sizeof(*si->entries)*numterms);
+ for (i = 0; i < numterms; i++)
+ {
+ zint g = rset_count(terms[i]->rset);
+ yaz_log(log_level, "i=%d flags=%s '%s'", i,
+ terms[i]->flags, terms[i]->name );
+ if (!strncmp (terms[i]->flags, "rank,", 5))
+ {
+ const char *cp = strstr(terms[i]->flags+4, ",w=");
+ si->entries[i].rank_flag = 1;
+ if (cp)
+ si->entries[i].rank_weight = atoi (cp+3);
+ else
+ si->entries[i].rank_weight = 34; /* sqrroot of 1000 */
+ yaz_log(log_level, " i=%d weight=%d g="ZINT_FORMAT, i,
+ si->entries[i].rank_weight, g);
+ (si->no_rank_entries)++;
+ }
+ else
+ si->entries[i].rank_flag = 0;
+ si->entries[i].local_occur = 0; /* FIXME */
+ si->entries[i].global_occur = g;
+ si->entries[i].global_inv = 32 - log2_int (g);
+ yaz_log(log_level, " global_inv = %d g = " ZINT_FORMAT,
+ (int) (32-log2_int (g)), g);
+ si->entries[i].term = terms[i];
+ si->entries[i].term_index=i;
+ terms[i]->rankpriv = &(si->entries[i]);
+ }
+ return si;
+}
+
+
+where g = rset_count(terms[i]->rset) is the count of all documents in this specific index hit list, and the IDF part then is
+
+ si->entries[i].global_inv = 32 - log2_int (g);
+ -->
+
+ </para>
+
+
+ <para>
+ The <literal>rank-1</literal> algorithm
+ does not use the static rank
+ information in the list keys, and will produce the same ordering
+ with or without static ranking enabled.
+ </para>
+
+
+ <!--
+ <sect3 id="administration-ranking-dynamic-rank1">
+ <title>Dynamically ranking &acro.pqf; queries with the 'rank-static'
+ algorithm</title>
+ <para>
+ The dummy <literal>rank-static</literal> reranking/scoring
+ function returns just
+ <literal>score = max int - staticrank</literal>
+ in order to preserve the static ordering of hit sets that would
+ have been produced had it not been invoked.
+ Obviously, to combine static and dynamic ranking usefully,
+ it is necessary
+ to make a new ranking
+ function; this is left
+ as an exercise for the reader.
+ </para>
+ </sect3>
+ -->
+
+ <warning>
+ <para>
+ <literal>Dynamic ranking</literal> is not compatible
+ with <literal>estimated hit sizes</literal>, as all documents in
+ a hit set must be accessed to compute the correct placing in a
+ ranking sorted list. Therefore the use attribute setting
+ <literal>@attr 2=102</literal> clashes with
+ <literal>@attr 9=integer</literal>.
+ </para>
+ </warning>
+
+ <!--
+ we might want to add ranking like this:
+ UNPUBLISHED:
+ Simple BM25 Extension to Multiple Weighted Fields
+ Stephen Robertson, Hugo Zaragoza and Michael Taylor
+ Microsoft Research
+ ser@microsoft.com
+ hugoz@microsoft.com
+ mitaylor2microsoft.com
+ -->
+
+ </sect3>
+
+ <sect3 id="administration-ranking-dynamic-cql">
+ <title>Dynamically ranking &acro.cql; queries</title>
+ <para>
+ Dynamic ranking can be enabled during sever side &acro.cql;
+ query expansion by adding <literal>@attr 2=102</literal>
+ chunks to the &acro.cql; config file. For example
+ <screen>
+ relationModifier.relevant = 2=102
+ </screen>
+ invokes dynamic ranking each time a &acro.cql; query of the form
+ <screen>
+ Z> querytype cql
+ Z> f alvis.text =/relevant house
+ </screen>
+ is issued. Dynamic ranking can also be automatically used on
+ specific &acro.cql; indexes by (for example) setting
+ <screen>
+ index.alvis.text = 1=text 2=102
+ </screen>
+ which then invokes dynamic ranking each time a &acro.cql; query of the form
+ <screen>
+ Z> querytype cql
+ Z> f alvis.text = house
+ </screen>
+ is issued.
+ </para>
+
+ </sect3>
+
+ </sect2>
+
+
+ <sect2 id="administration-ranking-sorting">
+ <title>Sorting</title>
+ <para>
+ &zebra; sorts efficiently using special sorting indexes
+ (type=<literal>s</literal>; so each sortable index must be known
+ at indexing time, specified in the configuration of record
+ indexing. For example, to enable sorting according to the &acro.bib1;
+ <literal>Date/time-added-to-db</literal> field, one could add the line
+ <screen>
+ xelm /*/@created Date/time-added-to-db:s
+ </screen>
+ to any <literal>.abs</literal> record-indexing configuration file.
+ Similarly, one could add an indexing element of the form
+ <screen><![CDATA[
+ <z:index name="date-modified" type="s">
+ <xsl:value-of select="some/xpath"/>
+ </z:index>
+ ]]></screen>
+ to any <literal>alvis</literal>-filter indexing stylesheet.
+ </para>
+ <para>
+ Indexing can be specified at searching time using a query term
+ carrying the non-standard
+ &acro.bib1; attribute-type <literal>7</literal>. This removes the
+ need to send a &acro.z3950; <literal>Sort Request</literal>
+ separately, and can dramatically improve latency when the client
+ and server are on separate networks.
+ The sorting part of the query is separate from the rest of the
+ query - the actual search specification - and must be combined
+ with it using OR.
+ </para>
+ <para>
+ A sorting subquery needs two attributes: an index (such as a
+ &acro.bib1; type-1 attribute) specifying which index to sort on, and a
+ type-7 attribute whose value is be <literal>1</literal> for
+ ascending sorting, or <literal>2</literal> for descending. The
+ term associated with the sorting attribute is the priority of
+ the sort key, where <literal>0</literal> specifies the primary
+ sort key, <literal>1</literal> the secondary sort key, and so
+ on.
+ </para>
+ <para>For example, a search for water, sort by title (ascending),
+ is expressed by the &acro.pqf; query
+ <screen>
+ @or @attr 1=1016 water @attr 7=1 @attr 1=4 0
+ </screen>
+ whereas a search for water, sort by title ascending,
+ then date descending would be
+ <screen>
+ @or @or @attr 1=1016 water @attr 7=1 @attr 1=4 0 @attr 7=2 @attr 1=30 1
+ </screen>
+ </para>
+ <para>
+ Notice the fundamental differences between <literal>dynamic
+ ranking</literal> and <literal>sorting</literal>: there can be
+ only one ranking function defined and configured; but multiple
+ sorting indexes can be specified dynamically at search
+ time. Ranking does not need to use specific indexes, so
+ dynamic ranking can be enabled and disabled without
+ re-indexing; whereas, sorting indexes need to be
+ defined before indexing.
+ </para>
+
+ </sect2>
+
+
+ </sect1>
+
+ <sect1 id="administration-extended-services">
+ <title>Extended Services: Remote Insert, Update and Delete</title>
+
+ <note>
+ <para>
+ Extended services are only supported when accessing the &zebra;
+ server using the <ulink url="&url.z39.50;">&acro.z3950;</ulink>
+ protocol. The <ulink url="&url.sru;">&acro.sru;</ulink> protocol does
+ not support extended services.
+ </para>
+ </note>
+
+ <para>
+ The extended services are not enabled by default in zebra - due to the
+ fact that they modify the system. &zebra; can be configured
+ to allow anybody to
+ search, and to allow only updates for a particular admin user
+ in the main zebra configuration file <filename>zebra.cfg</filename>.
+ For user <literal>admin</literal>, you could use:
+ <screen>
+ perm.anonymous: r
+ perm.admin: rw
+ passwd: passwordfile
+ </screen>
+ And in the password file
+ <filename>passwordfile</filename>, you have to specify users and
+ encrypted passwords as colon separated strings.
+ Use a tool like <filename>htpasswd</filename>
+ to maintain the encrypted passwords.
+ <screen>
+ admin:secret
+ </screen>
+ It is essential to configure &zebra; to store records internally,
+ and to support
+ modifications and deletion of records:
+ <screen>
+ storeData: 1
+ storeKeys: 1
+ </screen>
+ The general record type should be set to any record filter which
+ is able to parse &acro.xml; records, you may use any of the two
+ declarations (but not both simultaneously!)
+ <screen>
+ recordType: dom.filter_dom_conf.xml
+ # recordType: grs.xml
+ </screen>
+ Notice the difference to the specific instructions
+ <screen>
+ recordType.xml: dom.filter_dom_conf.xml
+ # recordType.xml: grs.xml
+ </screen>
+ which only work when indexing XML files from the filesystem using
+ the <literal>*.xml</literal> naming convention.
+ </para>
+ <para>
+ To enable transaction safe shadow indexing,
+ which is extra important for this kind of operation, set
+ <screen>
+ shadow: directoryname: size (e.g. 1000M)
+ </screen>
+ See <xref linkend="zebra-cfg"/> for additional information on
+ these configuration options.
+ </para>
+ <note>
+ <para>
+ It is not possible to carry information about record types or
+ similar to &zebra; when using extended services, due to
+ limitations of the <ulink url="&url.z39.50;">&acro.z3950;</ulink>
+ protocol. Therefore, indexing filters can not be chosen on a
+ per-record basis. One and only one general &acro.xml; indexing filter
+ must be defined.
+ <!-- but because it is represented as an OID, we would need some
+ form of proprietary mapping scheme between record type strings and
+ OIDs. -->
+ <!--
+ However, as a minimum, it would be extremely useful to enable
+ people to use &acro.marc21;, assuming grs.marcxml.marc21 as a record
+ type.
+ -->
+ </para>
+ </note>
+
+
+ <sect2 id="administration-extended-services-z3950">
+ <title>Extended services in the &acro.z3950; protocol</title>
+
+ <para>
+ The <ulink url="&url.z39.50;">&acro.z3950;</ulink> standard allows
+ servers to accept special binary <emphasis>extended services</emphasis>
+ protocol packages, which may be used to insert, update and delete
+ records into servers. These carry control and update
+ information to the servers, which are encoded in seven package fields:
+ </para>
+
+ <table id="administration-extended-services-z3950-table" frame="top">
+ <title>Extended services &acro.z3950; Package Fields</title>
+ <tgroup cols="3">
+ <thead>
+ <row>
+ <entry>Parameter</entry>
+ <entry>Value</entry>
+ <entry>Notes</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal>type</literal></entry>
+ <entry><literal>'update'</literal></entry>
+ <entry>Must be set to trigger extended services</entry>
+ </row>
+ <row>
+ <entry><literal>action</literal></entry>
+ <entry><literal>string</literal></entry>
+ <entry>
+ Extended service action type with
+ one of four possible values: <literal>recordInsert</literal>,
+ <literal>recordReplace</literal>,
+ <literal>recordDelete</literal>,
+ and <literal>specialUpdate</literal>
+ </entry>
+ </row>
+ <row>
+ <entry><literal>record</literal></entry>
+ <entry><literal>&acro.xml; string</literal></entry>
+ <entry>An &acro.xml; formatted string containing the record</entry>
+ </row>
+ <row>
+ <entry><literal>syntax</literal></entry>
+ <entry><literal>'xml'</literal></entry>
+ <entry>XML/SUTRS/MARC. GRS-1 not supported.
+ The default filter (record type) as given by recordType in
+ zebra.cfg is used to parse the record.</entry>
+ </row>
+ <row>
+ <entry><literal>recordIdOpaque</literal></entry>
+ <entry><literal>string</literal></entry>
+ <entry>
+ Optional client-supplied, opaque record
+ identifier used under insert operations.
+ </entry>
+ </row>
+ <row>
+ <entry><literal>recordIdNumber </literal></entry>
+ <entry><literal>positive number</literal></entry>
+ <entry>&zebra;'s internal system number,
+ not allowed for <literal>recordInsert</literal> or
+ <literal>specialUpdate</literal> actions which result in fresh
+ record inserts.
+ </entry>
+ </row>
+ <row>
+ <entry><literal>databaseName</literal></entry>
+ <entry><literal>database identifier</literal></entry>
+ <entry>
+ The name of the database to which the extended services should be
+ applied.
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+
+ <para>
+ The <literal>action</literal> parameter can be any of
+ <literal>recordInsert</literal> (will fail if the record already exists),
+ <literal>recordReplace</literal> (will fail if the record does not exist),
+ <literal>recordDelete</literal> (will fail if the record does not
+ exist), and
+ <literal>specialUpdate</literal> (will insert or update the record
+ as needed, record deletion is not possible).
+ </para>
+
+ <para>
+ During all actions, the
+ usual rules for internal record ID generation apply, unless an
+ optional <literal>recordIdNumber</literal> &zebra; internal ID or a
+ <literal>recordIdOpaque</literal> string identifier is assigned.
+ The default ID generation is
+ configured using the <literal>recordId:</literal> from
+ <filename>zebra.cfg</filename>.
+ See <xref linkend="zebra-cfg"/>.
+ </para>
+
+ <para>
+ Setting of the <literal>recordIdNumber</literal> parameter,
+ which must be an existing &zebra; internal system ID number, is not
+ allowed during any <literal>recordInsert</literal> or
+ <literal>specialUpdate</literal> action resulting in fresh record
+ inserts.
+ </para>
+
+ <para>
+ When retrieving existing
+ records indexed with &acro.grs1; indexing filters, the &zebra; internal
+ ID number is returned in the field
+ <literal>/*/id:idzebra/localnumber</literal> in the namespace
+ <literal>xmlns:id="http://www.indexdata.dk/zebra/"</literal>,
+ where it can be picked up for later record updates or deletes.
+ </para>
+
+ <para>
+ A new element set for retrieval of internal record
+ data has been added, which can be used to access minimal records
+ containing only the <literal>recordIdNumber</literal> &zebra;
+ internal ID, or the <literal>recordIdOpaque</literal> string
+ identifier. This works for any indexing filter used.
+ See <xref linkend="special-retrieval"/>.
+ </para>
+
+ <para>
+ The <literal>recordIdOpaque</literal> string parameter
+ is an client-supplied, opaque record
+ identifier, which may be used under
+ insert, update and delete operations. The
+ client software is responsible for assigning these to
+ records. This identifier will
+ replace zebra's own automagic identifier generation with a unique
+ mapping from <literal>recordIdOpaque</literal> to the
+ &zebra; internal <literal>recordIdNumber</literal>.
+ <emphasis>The opaque <literal>recordIdOpaque</literal> string
+ identifiers
+ are not visible in retrieval records, nor are
+ searchable, so the value of this parameter is
+ questionable. It serves mostly as a convenient mapping from
+ application domain string identifiers to &zebra; internal ID's.
+ </emphasis>
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-extended-services-yaz-client">
+ <title>Extended services from yaz-client</title>
+
+ <para>
+ We can now start a yaz-client admin session and create a database:
+ <screen>
+ <![CDATA[
+ $ yaz-client localhost:9999 -u admin/secret
+ Z> adm-create
+ ]]>
+ </screen>
+ Now the <literal>Default</literal> database was created,
+ we can insert an &acro.xml; file (esdd0006.grs
+ from example/gils/records) and index it:
+ <screen>
+ <![CDATA[
+ Z> update insert id1234 esdd0006.grs
+ ]]>
+ </screen>
+ The 3rd parameter - <literal>id1234</literal> here -
+ is the <literal>recordIdOpaque</literal> package field.
+ </para>
+ <para>
+ Actually, we should have a way to specify "no opaque record id" for
+ yaz-client's update command.. We'll fix that.
+ </para>
+ <para>
+ The newly inserted record can be searched as usual:
+ <screen>
+ <![CDATA[
+ Z> f utah
+ Sent searchRequest.
+ Received SearchResponse.
+ Search was a success.
+ Number of hits: 1, setno 1
+ SearchResult-1: term=utah cnt=1
+ records returned: 0
+ Elapsed: 0.014179
+ ]]>
+ </screen>
+ </para>
+ <para>
+ Let's delete the beast, using the same
+ <literal>recordIdOpaque</literal> string parameter:
+ <screen>
+ <![CDATA[
+ Z> update delete id1234
+ No last record (update ignored)
+ Z> update delete 1 esdd0006.grs
+ Got extended services response
+ Status: done
+ Elapsed: 0.072441
+ Z> f utah
+ Sent searchRequest.
+ Received SearchResponse.
+ Search was a success.
+ Number of hits: 0, setno 2
+ SearchResult-1: term=utah cnt=0
+ records returned: 0
+ Elapsed: 0.013610
+ ]]>
+ </screen>
+ </para>
+ <para>
+ If shadow register is enabled in your
+ <filename>zebra.cfg</filename>,
+ you must run the adm-commit command
+ <screen>
+ <![CDATA[
+ Z> adm-commit
+ ]]>
+ </screen>
+ after each update session in order write your changes from the
+ shadow to the life register space.
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-extended-services-yaz-php">
+ <title>Extended services from yaz-php</title>
+
+ <para>
+ Extended services are also available from the &yaz; &acro.php; client layer. An
+ example of an &yaz;-&acro.php; extended service transaction is given here:
+ <screen>
+ <![CDATA[
+ $record = '<record><title>A fine specimen of a record</title></record>';
+
+ $options = array('action' => 'recordInsert',
+ 'syntax' => 'xml',
+ 'record' => $record,
+ 'databaseName' => 'mydatabase'
+ );
+
+ yaz_es($yaz, 'update', $options);
+ yaz_es($yaz, 'commit', array());
+ yaz_wait();
+
+ if ($error = yaz_error($yaz))
+ echo "$error";
+ ]]>
+ </screen>
+ </para>
+ </sect2>
+
+ <sect2 id="administration-extended-services-debugging">
+ <title>Extended services debugging guide</title>
+ <para>
+ When debugging ES over PHP we recommend the following order of tests:
+ </para>
+
+ <itemizedlist>
+ <listitem>
+ <para>
+ Make sure you have a nice record on your filesystem, which you can
+ index from the filesystem by use of the zebraidx command.
+ Do it exactly as you planned, using one of the GRS-1 filters,
+ or the DOMXML filter.
+ When this works, proceed.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Check that your server setup is OK before you even coded one single
+ line PHP using ES.
+ Take the same record form the file system, and send as ES via
+ <literal>yaz-client</literal> like described in
+ <xref linkend="administration-extended-services-yaz-client"/>,
+ and
+ remember the <literal>-a</literal> option which tells you what
+ goes over the wire! Notice also the section on permissions:
+ try
+ <screen>
+ perm.anonymous: rw
+ </screen>
+ in <literal>zebra.cfg</literal> to make sure you do not run into
+ permission problems (but never expose such an insecure setup on the
+ internet!!!). Then, make sure to set the general
+ <literal>recordType</literal> instruction, pointing correctly
+ to the GRS-1 filters,
+ or the DOMXML filters.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ If you insist on using the <literal>sysno</literal> in the
+ <literal>recordIdNumber</literal> setting,
+ please make sure you do only updates and deletes. Zebra's internal
+ system number is not allowed for
+ <literal>recordInsert</literal> or
+ <literal>specialUpdate</literal> actions
+ which result in fresh record inserts.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ If <literal>shadow register</literal> is enabled in your
+ <literal>zebra.cfg</literal>, you must remember running the
+ <screen>
+ Z> adm-commit
+ </screen>
+ command as well.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ If this works, then proceed to do the same thing in your PHP script.
+ </para>
+ </listitem>
+ </itemizedlist>
+
+
+ </sect2>
+
+ </sect1>
</chapter>
-<chapter id="zebraidx">
-<title>Running the Maintenance Interface (zebraidx)</title>
-
-<para>
-The following is a complete reference to the command line interface to
-the <literal remap="tt">zebraidx</literal> application.
-</para>
-
-<para>
-<emphasis remap="bf">Syntax</emphasis>
-
-<screen>
-$ zebraidx [options] command [directory] ...
-</screen>
-
-<emphasis remap="bf">Options</emphasis>
-<variablelist>
-
-<varlistentry>
-<term>-t <emphasis remap="it">type</emphasis></term>
-<listitem>
-<para>
-Update all files as <emphasis remap="it">type</emphasis>. Currently, the
-types supported are <literal remap="tt">text</literal> and <literal remap="tt">grs</literal><emphasis remap="it">.subtype</emphasis>. If no
-<emphasis remap="it">subtype</emphasis> is provided for the GRS (General Record Structure) type,
-the canonical input format is assumed (see section <xref linkend="local-representation"/>). Generally, it
-is probably advisable to specify the record types in the
-<literal remap="tt">zebra.cfg</literal> file
-(see section <xref linkend="record-types"/>), to avoid
-confusion at subsequent updates.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-c <emphasis remap="it">config-file</emphasis></term>
-<listitem>
-<para>
-Read the configuration file
-<emphasis remap="it">config-file</emphasis> instead of <literal remap="tt">zebra.cfg</literal>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-g <emphasis remap="it">group</emphasis></term>
-<listitem>
-<para>
-Update the files according to the group
-settings for <emphasis remap="it">group</emphasis> (see section
-<xref linkend="configuration-file"/>).
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-d <emphasis remap="it">database</emphasis></term>
-<listitem>
-<para>
-The records located should be associated
-with the database name <emphasis remap="it">database</emphasis> for access through the Z39.50
-server.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-m <emphasis remap="it">mbytes</emphasis></term>
-<listitem>
-<para>
-Use <emphasis remap="it">mbytes</emphasis> of megabytes before flushing
-keys to background storage. This setting affects performance when
-updating large databases.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-n</term>
-<listitem>
-<para>
-Disable the use of shadow registers for this operation
-(see section <xref linkend="shadow-registers"/>).
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-s</term>
-<listitem>
-<para>
-Show analysis of the indexing process. The maintenance
-program works in a read-only mode and doesn't change the state
-of the index. This options is very useful when you wish to test a
-new profile.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-V</term>
-<listitem>
-<para>
-Show Zebra version.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-v <emphasis remap="it">level</emphasis></term>
-<listitem>
-<para>
-Set the log level to <emphasis remap="it">level</emphasis>. <emphasis remap="it">level</emphasis>
-should be one of <literal remap="tt">none</literal>, <literal remap="tt">debug</literal>, and <literal remap="tt">all</literal>.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-<para>
-<emphasis remap="bf">Commands</emphasis>
-<variablelist>
-
-<varlistentry>
-<term>Update <emphasis remap="it">directory</emphasis></term>
-<listitem>
-<para>
-Update the register with the files
-contained in <emphasis remap="it">directory</emphasis>. If no directory is provided, a list of
-files is read from <literal remap="tt">stdin</literal>.
-See section <xref linkend="administration"/>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>Delete <emphasis remap="it">directory</emphasis></term>
-<listitem>
-<para>
-Remove the records corresponding to
-the files found under <emphasis remap="it">directory</emphasis> from the register.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>Commit</term>
-<listitem>
-<para>
-Write the changes resulting from the last <emphasis remap="bf">update</emphasis>
-commands to the register. This command is only available if the use of
-shadow register files is enabled (see section
-<xref linkend="shadow-registers"/>).
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-</chapter>
-
-<chapter id="server">
-<title>The Z39.50 Server</title>
-
-<sect1 id="zebrasrv">
-<title>Running the Z39.50 Server (zebrasrv)</title>
-
-<para>
-<emphasis remap="bf">Syntax</emphasis>
-
-<screen>
-zebrasrv [options] [listener-address ...]
-</screen>
-
-</para>
-
-<para>
-<emphasis remap="bf">Options</emphasis>
-<variablelist>
-
-<varlistentry>
-<term>-a <emphasis remap="it">APDU file</emphasis></term>
-<listitem>
-<para>
-Specify a file for dumping PDUs (for diagnostic purposes).
-The special name "-" sends output to <literal>stderr</literal>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-c <emphasis remap="it">config-file</emphasis></term>
-<listitem>
-<para>
-Read configuration information from <emphasis remap="it">config-file</emphasis>. The default configuration is <literal remap="tt">./zebra.cfg</literal>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-S</term>
-<listitem>
-<para>
-Don't fork on connection requests. This can be useful for
-symbolic-level debugging. The server can only accept a single
-connection in this mode.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-s</term>
-<listitem>
-<para>
-Use the SR protocol.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-z</term>
-<listitem>
-<para>
-Use the Z39.50 protocol (default). These two options complement
-eachother. You can use both multiple times on the same command
-line, between listener-specifications (see below). This way, you
-can set up the server to listen for connections in both protocols
-concurrently, on different local ports.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-l <emphasis remap="it">logfile</emphasis></term>
-<listitem>
-<para>
-Specify an output file for the diagnostic
-messages. The default is to write this information to <literal remap="tt">stderr</literal>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-v <emphasis remap="it">log-level</emphasis></term>
-<listitem>
-<para>
-The log level. Use a comma-separated list of members of the set
-{fatal,debug,warn,log,all,none}.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-u <emphasis remap="it">username</emphasis></term>
-<listitem>
-<para>
-Set user ID. Sets the real UID of the server process to that of the
-given <emphasis remap="it">username</emphasis>. It's useful if you aren't comfortable with having the
-server run as root, but you need to start it as such to bind a
-privileged port.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-w <emphasis remap="it">working-directory</emphasis></term>
-<listitem>
-<para>
-Change working directory.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-i</term>
-<listitem>
-<para>
-Run under the Internet superserver, <literal remap="tt">inetd</literal>. Make
-sure you use the logfile option <literal remap="tt">-l</literal> in conjunction with this
-mode and specify the <literal remap="tt">-l</literal> option before any other options.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-t <emphasis remap="it">timeout</emphasis></term>
-<listitem>
-<para>
-Set the idle session timeout (default 60 minutes).
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>-k <emphasis remap="it">kilobytes</emphasis></term>
-<listitem>
-<para>
-Set the (approximate) maximum size of
-present response messages. Default is 1024 Kb (1 Mb).
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-<para>
-A <emphasis remap="it">listener-address</emphasis> consists of a transport mode followed by a
-colon (:) followed by a listener address. The transport mode is
-either <literal remap="tt">osi</literal> or <literal remap="tt">tcp</literal>.
-</para>
-
-<para>
-For TCP, an address has the form
-</para>
-
-<para>
-
-<screen>
-hostname | IP-number [: portnumber]
-</screen>
-
-</para>
-
-<para>
-The port number defaults to 210 (standard Z39.50 port).
-</para>
-
-<para>
-For OSI (only available if the server is compiled with XTI/mOSI
-support enabled), the address form is
-</para>
-
-<para>
-
-<screen>
-[t-selector /] hostname | IP-number [: portnumber]
-</screen>
-
-</para>
-
-<para>
-The transport selector is given as a string of hex digits (with an even
-number of digits). The default port number is 102 (RFC1006 port).
-</para>
-
-<para>
-Examples
-</para>
-
-<para>
-
-<screen>
-tcp:dranet.dra.com
-
-osi:0402/dbserver.osiworld.com:3000
-</screen>
-
-</para>
-
-<para>
-In both cases, the special hostname "@" is mapped to
-the address INADDR_ANY, which causes the server to listen on any local
-interface. To start the server listening on the registered ports for
-Z39.50 and SR over OSI/RFC1006, and to drop root privileges once the
-ports are bound, execute the server like this (from a root shell):
-</para>
-
-<para>
-
-<screen>
-zebrasrv -u daemon tcp:@ -s osi:@
-</screen>
-
-</para>
-
-<para>
-You can replace <literal remap="tt">daemon</literal> with another user, eg. your own account, or
-a dedicated IR server account.
-</para>
-
-<para>
-The default behavior for <literal remap="tt">zebrasrv</literal> is to establish a single TCP/IP
-listener, for the Z39.50 protocol, on port 9999.
-</para>
-
-</sect1>
-
-<sect1 id="protocol-support">
-<title>Z39.50 Protocol Support and Behavior</title>
-
-<sect2>
-<title>Initialization</title>
-
-<para>
-During initialization, the server will negotiate to version 3 of the
-Z39.50 protocol, and the option bits for Search, Present, Scan,
-NamedResultSets, and concurrentOperations will be set, if requested by
-the client. The maximum PDU size is negotiated down to a maximum of
-1Mb by default.
-</para>
-
-</sect2>
-
-<sect2 id="search">
-<title>Search</title>
-
-<para>
-The supported query type are 1 and 101. All operators are currently
-supported with the restriction that only proximity units of type "word" are
-supported for the proximity operator.
-Queries can be arbitrarily complex.
-Named result sets are supported, and result sets can be used as operands
-without limitations.
-Searches may span multiple databases.
-</para>
-
-<para>
-The server has full support for piggy-backed present requests (see
-also the following section).
-</para>
-
-<para>
-<emphasis remap="bf">Use</emphasis> attributes are interpreted according to the attribute sets which
-have been loaded in the <literal remap="tt">zebra.cfg</literal> file, and are matched against
-specific fields as specified in the <literal remap="tt">.abs</literal> file which describes the
-profile of the records which have been loaded. If no <emphasis remap="bf">Use</emphasis>
-attribute is provided, a default of Bib-1 <emphasis remap="bf">Any</emphasis> is assumed.
-</para>
-
-<para>
-If a <emphasis remap="bf">Structure</emphasis> attribute of <emphasis remap="bf">Phrase</emphasis> is used in conjunction with a
-<emphasis remap="bf">Completeness</emphasis> attribute of <emphasis remap="bf">Complete (Sub)field</emphasis>, the term is
-matched against the contents of the phrase (long word) register, if one
-exists for the given <emphasis remap="bf">Use</emphasis> attribute.
-A phrase register is created for those fields in the <literal remap="tt">.abs</literal>
-file that contains a <literal remap="tt">p</literal>-specifier.
-</para>
-
-<para>
-If <emphasis remap="bf">Structure</emphasis>=<emphasis remap="bf">Phrase</emphasis> is used in conjunction with
-<emphasis remap="bf">Incomplete Field</emphasis> - the default value for <emphasis remap="bf">Completeness</emphasis>, the
-search is directed against the normal word registers, but if the term
-contains multiple words, the term will only match if all of the words
-are found immediately adjacent, and in the given order.
-The word search is performed on those fields that are indexed as
-type <literal remap="tt">w</literal> in the <literal remap="tt">.abs</literal> file.
-</para>
-
-<para>
-If the <emphasis remap="bf">Structure</emphasis> attribute is <emphasis remap="bf">Word List</emphasis>,
-<emphasis remap="bf">Free-form Text</emphasis>, or <emphasis remap="bf">Document Text</emphasis>, the term is treated as a
-natural-language, relevance-ranked query.
-This search type uses the word register, i.e. those fields
-that are indexed as type <literal remap="tt">w</literal> in the <literal remap="tt">.abs</literal> file.
-</para>
-
-<para>
-If the <emphasis remap="bf">Structure</emphasis> attribute is <emphasis remap="bf">Numeric String</emphasis> the
-term is treated as an integer. The search is performed on those
-fields that are indexed as type <literal remap="tt">n</literal> in the <literal remap="tt">.abs</literal> file.
-</para>
-
-<para>
-If the <emphasis remap="bf">Structure</emphasis> attribute is <emphasis remap="bf">URx</emphasis> the
-term is treated as a URX (URL) entity. The search is performed on those
-fields that are indexed as type <literal remap="tt">u</literal> in the <literal remap="tt">.abs</literal> file.
-</para>
-
-<para>
-If the <emphasis remap="bf">Structure</emphasis> attribute is <emphasis remap="bf">Local Number</emphasis> the
-term is treated as native Zebra Record Identifier.
-</para>
-
-<para>
-If the <emphasis remap="bf">Relation</emphasis> attribute is <emphasis remap="bf">Equals</emphasis> (default), the term is
-matched in a normal fashion (modulo truncation and processing of
-individual words, if required). If <emphasis remap="bf">Relation</emphasis> is <emphasis remap="bf">Less Than</emphasis>,
-<emphasis remap="bf">Less Than or Equal</emphasis>, <emphasis remap="bf">Greater than</emphasis>, or <emphasis remap="bf">Greater than or
-Equal</emphasis>, the term is assumed to be numerical, and a standard regular
-expression is constructed to match the given expression. If
-<emphasis remap="bf">Relation</emphasis> is <emphasis remap="bf">Relevance</emphasis>, the standard natural-language query
-processor is invoked.
-</para>
-
-<para>
-For the <emphasis remap="bf">Truncation</emphasis> attribute, <emphasis remap="bf">No Truncation</emphasis> is the default.
-<emphasis remap="bf">Left Truncation</emphasis> is not supported. <emphasis remap="bf">Process #</emphasis> is supported, as
-is <emphasis remap="bf">Regxp-1</emphasis>. <emphasis remap="bf">Regxp-2</emphasis> enables the fault-tolerant (fuzzy)
-search. As a default, a single error (deletion, insertion,
-replacement) is accepted when terms are matched against the register
-contents.
-</para>
-
-<sect3>
-<title>Regular expressions</title>
-
-<para>
-Each term in a query is interpreted as a regular expression if
-the truncation value is either <emphasis remap="bf">Regxp-1</emphasis> (102) or <emphasis remap="bf">Regxp-2</emphasis> (103).
-Both query types follow the same syntax with the operands:
-<variablelist>
-
-<varlistentry>
-<term>x</term>
-<listitem>
-<para>
-Matches the character <emphasis remap="it">x</emphasis>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>.</term>
-<listitem>
-<para>
-Matches any character.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term><literal remap="tt">[</literal>..<literal remap="tt">]</literal></term>
-<listitem>
-<para>
-Matches the set of characters specified;
-such as <literal remap="tt">[abc]</literal> or <literal remap="tt">[a-c]</literal>.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-and the operators:
-<variablelist>
-
-<varlistentry>
-<term>x*</term>
-<listitem>
-<para>
-Matches <emphasis remap="it">x</emphasis> zero or more times. Priority: high.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>x+</term>
-<listitem>
-<para>
-Matches <emphasis remap="it">x</emphasis> one or more times. Priority: high.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>x?</term>
-<listitem>
-<para>
-Matches <emphasis remap="it">x</emphasis> once or twice. Priority: high.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>xy</term>
-<listitem>
-<para>
-Matches <emphasis remap="it">x</emphasis>, then <emphasis remap="it">y</emphasis>. Priority: medium.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>x|y</term>
-<listitem>
-<para>
-Matches either <emphasis remap="it">x</emphasis> or <emphasis remap="it">y</emphasis>. Priority: low.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-The order of evaluation may be changed by using parentheses.
-</para>
-
-<para>
-If the first character of the <emphasis remap="bf">Regxp-2</emphasis> query is a plus character
-(<literal remap="tt">+</literal>) it marks the beginning of a section with non-standard
-specifiers. The next plus character marks the end of the section.
-Currently Zebra only supports one specifier, the error tolerance,
-which consists one digit.
-</para>
-
-<para>
-Since the plus operator is normally a suffix operator the addition to
-the query syntax doesn't violate the syntax for standard regular
-expressions.
-</para>
-
-</sect3>
-
-<sect3>
-<title>Query examples</title>
-
-<para>
-Phrase search for <emphasis remap="bf">information retrieval</emphasis> in the title-register:
-
-<screen>
- @attr 1=4 "information retrieval"
-</screen>
-
-</para>
-
-<para>
-Ranked search for the same thing:
-
-<screen>
- @attr 1=4 @attr 2=102 "Information retrieval"
-</screen>
-
-</para>
-
-<para>
-Phrase search with a regular expression:
-
-<screen>
- @attr 1=4 @attr 5=102 "informat.* retrieval"
-</screen>
-
-</para>
-
-<para>
-Ranked search with a regular expression:
-
-<screen>
- @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval"
-</screen>
-
-</para>
-
-<para>
-In the GILS schema (<literal remap="tt">gils.abs</literal>), the west-bounding-coordinate is
-indexed as type <literal remap="tt">n</literal>, and is therefore searched by specifying
-<emphasis remap="bf">structure</emphasis>=<emphasis remap="bf">Numeric String</emphasis>.
-To match all those records with west-bounding-coordinate greater
-than -114 we use the following query:
-
-<screen>
- @attr 4=109 @attr 2=5 @attr gils 1=2038 -114
-</screen>
-
-</para>
-
-</sect3>
-
-</sect2>
-
-<sect2>
-<title>Present</title>
-
-<para>
-The present facility is supported in a standard fashion. The requested
-record syntax is matched against the ones supported by the profile of
-each record retrieved. If no record syntax is given, SUTRS is the
-default. The requested element set name, again, is matched against any
-provided by the relevant record profiles.
-</para>
-
-</sect2>
-
-<sect2>
-<title>Scan</title>
-
-<para>
-The attribute combinations provided with the termListAndStartPoint are
-processed in the same way as operands in a query (see above).
-Currently, only the term and the globalOccurrences are returned with
-the termInfo structure.
-</para>
-
-</sect2>
-
-<sect2>
-<title>Sort</title>
-
-<para>
-Z39.50 specifies three diffent types of sort criterias.
-Of these Zebra supports the attribute specification type in which
-case the use attribute specifies the "Sort register".
-Sort registers are created for those fields that are of type "sort" in
-the default.idx file.
-The corresponding character mapping file in default.idx specifies the
-ordinal of each character used in the actual sort.
-</para>
-
-<para>
-Z39.50 allows the client to specify sorting on one or more input
-result sets and one output result set.
-Zebra supports sorting on one result set only which may or may not
-be the same as the output result set.
-</para>
-
-</sect2>
-
-<sect2>
-<title>Close</title>
-
-<para>
-If a Close PDU is received, the server will respond with a Close PDU
-with reason=FINISHED, no matter which protocol version was negotiated
-during initialization. If the protocol version is 3 or more, the
-server will generate a Close PDU under certain circumstances,
-including a session timeout (60 minutes by default), and certain kinds of
-protocol errors. Once a Close PDU has been sent, the protocol
-association is considered broken, and the transport connection will be
-closed immediately upon receipt of further data, or following a short
-timeout.
-</para>
-
-</sect2>
-
-</sect1>
-
-</chapter>
-
-<chapter id="record-model">
-<title>The Record Model</title>
-
-<para>
-The Zebra system is designed to support a wide range of data management
-applications. The system can be configured to handle virtually any
-kind of structured data. Each record in the system is associated with
-a <emphasis remap="it">record schema</emphasis> which lends context to the data elements of the
-record. Any number of record schema can coexist in the system.
-Although it may be wise to use only a single schema within
-one database, the system poses no such restrictions.
-</para>
-
-<para>
-The record model described in this chapter applies to the fundamental,
-structured
-record type <literal remap="tt">grs</literal> as introduced in
-section <xref linkend="record-types"/>.
-</para>
-
-<para>
-Records pass through three different states during processing in the
-system.
-</para>
-
-<para>
-
-<itemizedlist>
-<listitem>
-
-<para>
-When records are accessed by the system, they are represented
-in their local, or native format. This might be SGML or HTML files,
-News or Mail archives, MARC records. If the system doesn't already
-know how to read the type of data you need to store, you can set up an
-input filter by preparing conversion rules based on regular
-expressions and possibly augmented by a flexible scripting language (Tcl). The input filter
-produces as output an internal representation:
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-When records are processed by the system, they are represented
-in a tree-structure, constructed by tagged data elements hanging off a
-root node. The tagged elements may contain data or yet more tagged
-elements in a recursive structure. The system performs various
-actions on this tree structure (indexing, element selection, schema
-mapping, etc.),
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-Before transmitting records to the client, they are first
-converted from the internal structure to a form suitable for exchange
-over the network - according to the Z39.50 standard.
-</para>
-</listitem>
-
-</itemizedlist>
-
-</para>
-
-<sect1 id="local-representation">
-<title>Local Representation</title>
-
-<para>
-As mentioned earlier, Zebra places few restrictions on the type of
-data that you can index and manage. Generally, whatever the form of
-the data, it is parsed by an input filter specific to that format, and
-turned into an internal structure that Zebra knows how to handle. This
-process takes place whenever the record is accessed - for indexing and
-retrieval.
-</para>
-
-<para>
-The RecordType parameter in the <literal remap="tt">zebra.cfg</literal> file, or the <literal remap="tt">-t</literal>
-option to the indexer tells Zebra how to process input records. Two
-basic types of processing are available - raw text and structured
-data. Raw text is just that, and it is selected by providing the
-argument <emphasis remap="bf">text</emphasis> to Zebra. Structured records are all handled
-internally using the basic mechanisms described in the subsequent
-sections. Zebra can read structured records in many different formats.
-How this is done is governed by additional parameters after the
-"grs" keyboard, separated by "." characters.
-</para>
-
-<para>
-Three basic subtypes to the <emphasis remap="bf">grs</emphasis> type are currently available:
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>grs.sgml</term>
-<listitem>
-<para>
-This is the canonical input format —
-described below. It is a simple SGML-like syntax.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>grs.regx.<emphasis remap="it">filter</emphasis></term>
-<listitem>
-<para>
-This enables a user-supplied input
-filter. The mechanisms of these filters are described below.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>grs.marc.<emphasis remap="it">abstract syntax</emphasis></term>
-<listitem>
-<para>
-This allows Zebra to read
-records in the ISO2709 (MARC) encoding standard. In this case, the
-last paramemeter <emphasis remap="it">abstract syntax</emphasis> names the .abs file (see below)
-which describes the specific MARC structure of the input record as
-well as the indexing rules.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-<sect2>
-<title>Canonical Input Format</title>
-
-<para>
-Although input data can take any form, it is sometimes useful to
-describe the record processing capabilities of the system in terms of
-a single, canonical input format that gives access to the full
-spectrum of structure and flexibility in the system. In Zebra, this
-canonical format is an "SGML-like" syntax.
-</para>
-
-<para>
-To use the canonical format specify <literal remap="tt">grs.sgml</literal> as the record
-type,
-</para>
-
-<para>
-Consider a record describing an information resource (such a record is
-sometimes known as a <emphasis remap="it">locator record</emphasis>). It might contain a field
-describing the distributor of the information resource, which might in
-turn be partitioned into various fields providing details about the
-distributor, like this:
-</para>
-
-<para>
-
-<screen>
-<Distributor>
- <Name> USGS/WRD </Name>
- <Organization> USGS/WRD </Organization>
- <Street-Address>
- U.S. GEOLOGICAL SURVEY, 505 MARQUETTE, NW
- </Street-Address>
- <City> ALBUQUERQUE </City>
- <State> NM </State>
- <Zip-Code> 87102 </Zip-Code>
- <Country> USA </Country>
- <Telephone> (505) 766-5560 </Telephone>
-</Distributor>
-</screen>
-
-</para>
-
-<para>
-<emphasis remap="it">NOTE: The indentation used above is used to illustrate how Zebra
-interprets the markup. The indentation, in itself, has no
-significance to the parser for the canonical input format, which
-discards superfluous whitespace.</emphasis>
-</para>
-
-<para>
-The keywords surrounded by <...> are <emphasis remap="it">tags</emphasis>, while the
-sections of text in between are the <emphasis remap="it">data elements</emphasis>. A data element
-is characterized by its location in the tree that is made up by the
-nested elements. Each element is terminated by a closing tag -
-beginning with <literal remap="tt"><</literal>/, and containing the same symbolic tag-name as
-the corresponding opening tag. The general closing tag - <literal remap="tt"><</literal>>/ -
-terminates the element started by the last opening tag. The
-structuring of elements is significant. The element <emphasis remap="bf">Telephone</emphasis>,
-for instance, may be indexed and presented to the client differently,
-depending on whether it appears inside the <emphasis remap="bf">Distributor</emphasis> element,
-or some other, structured data element such a <emphasis remap="bf">Supplier</emphasis> element.
-</para>
-
-<sect3>
-<title>Record Root</title>
-
-<para>
-The first tag in a record describes the root node of the tree that
-makes up the total record. In the canonical input format, the root tag
-should contain the name of the schema that lends context to the
-elements of the record (see section
-<xref linkend="internal-representation"/>).
-The following is a GILS record that
-contains only a single element (strictly speaking, that makes it an
-illegal GILS record, since the GILS profile includes several mandatory
-elements - Zebra does not validate the contents of a record against
-the Z39.50 profile, however - it merely attempts to match up elements
-of a local representation with the given schema):
-</para>
-
-<para>
-
-<screen>
-<gils>
- <title>Zen and the Art of Motorcycle Maintenance</title>
-</gils>
-</screen>
-
-</para>
-
-</sect3>
-
-<sect3>
-<title>Variants</title>
-
-<para>
-Zebra allows you to provide individual data elements in a number of
-<emphasis remap="it">variant forms</emphasis>. Examples of variant forms are textual data
-elements which might appear in different languages, and images which
-may appear in different formats or layouts. The variant system in
-Zebra is
-essentially a representation of the variant mechanism of
-Z39.50-1995.
-</para>
-
-<para>
-The following is an example of a title element which occurs in two
-different languages.
-</para>
-
-<para>
-
-<screen>
-<title>
- <var lang lang "eng">
- Zen and the Art of Motorcycle Maintenance</>
- <var lang lang "dan">
- Zen og Kunsten at Vedligeholde en Motorcykel</>
-</title>
-</screen>
-
-</para>
-
-<para>
-The syntax of the <emphasis remap="it">variant element</emphasis> is <literal remap="tt"><var class
-type value></literal>. The available values for the <emphasis remap="it">class</emphasis> and
-<emphasis remap="it">type</emphasis> fields are given by the variant set that is associated with the
-current schema (see section <xref linkend="variant-set"/>).
-</para>
-
-<para>
-Variant elements are terminated by the general end-tag </>, by
-the variant end-tag </var>, by the appearance of another variant
-tag with the same <emphasis remap="it">class</emphasis> and <emphasis remap="it">value</emphasis> settings, or by the
-appearance of another, normal tag. In other words, the end-tags for
-the variants used in the example above could have been saved.
-</para>
-
-<para>
-Variant elements can be nested. The element
-</para>
-
-<para>
-
-<screen>
-<title>
- <var lang lang "eng"><var body iana "text/plain">
- Zen and the Art of Motorcycle Maintenance
-</title>
-</screen>
-
-</para>
-
-<para>
-Associates two variant components to the variant list for the title
-element.
-</para>
-
-<para>
-Given the nesting rules described above, we could write
-</para>
-
-<para>
-
-<screen>
-<title>
- <var body iana "text/plain>
- <var lang lang "eng">
- Zen and the Art of Motorcycle Maintenance
- <var lang lang "dan">
- Zen og Kunsten at Vedligeholde en Motorcykel
-</title>
-</screen>
-
-</para>
-
-<para>
-The title element above comes in two variants. Both have the IANA body
-type "text/plain", but one is in English, and the other in
-Danish. The client, using the element selection mechanism of Z39.50,
-can retrieve information about the available variant forms of data
-elements, or it can select specific variants based on the requirements
-of the end-user.
-</para>
-
-</sect3>
-
-</sect2>
-
-<sect2>
-<title>Input Filters</title>
-
-<para>
-In order to handle general input formats, Zebra allows the
-operator to define filters which read individual records in their native format
-and produce an internal representation that the system can
-work with.
-</para>
-
-<para>
-Input filters are ASCII files, generally with the suffix <literal remap="tt">.flt</literal>.
-The system looks for the files in the directories given in the
-<emphasis remap="bf">profilePath</emphasis> setting in the <literal remap="tt">zebra.cfg</literal> files. The record type
-for the filter is <literal remap="tt">grs.regx.</literal><emphasis remap="it">filter-filename</emphasis>
-(fundamental type <literal remap="tt">grs</literal>, file read type <literal remap="tt">regx</literal>, argument
-<emphasis remap="it">filter-filename</emphasis>).
-</para>
-
-<para>
-Generally, an input filter consists of a sequence of rules, where each
-rule consists of a sequence of expressions, followed by an action. The
-expressions are evaluated against the contents of the input record,
-and the actions normally contribute to the generation of an internal
-representation of the record.
-</para>
-
-<para>
-An expression can be either of the following:
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>INIT</term>
-<listitem>
-<para>
-The action associated with this expression is evaluated
-exactly once in the lifetime of the application, before any records
-are read. It can be used in conjunction with an action that
-initializes tables or other resources that are used in the processing
-of input records.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>BEGIN</term>
-<listitem>
-<para>
-Matches the beginning of the record. It can be used to
-initialize variables, etc. Typically, the <emphasis remap="bf">BEGIN</emphasis> rule is also used
-to establish the root node of the record.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>END</term>
-<listitem>
-<para>
-Matches the end of the record - when all of the contents
-of the record has been processed.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>/pattern/</term>
-<listitem>
-<para>
-Matches a string of characters from the input
-record.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>BODY</term>
-<listitem>
-<para>
-This keyword may only be used between two patterns. It
-matches everything between (not including) those patterns.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>FINISH</term>
-<listitem>
-<para>
-The expression asssociated with this pattern is evaluated
-once, before the application terminates. It can be used to release
-system resources - typically ones allocated in the <emphasis remap="bf">INIT</emphasis> step.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-<para>
-An action is surrounded by curly braces ({...}), and consists of a
-sequence of statements. Statements may be separated by newlines or
-semicolons (;). Within actions, the strings that matched the
-expressions immediately preceding the action can be referred to as
-$0, $1, $2, etc.
-</para>
-
-<para>
-The available statements are:
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>begin <emphasis remap="it">type [parameter ... ]</emphasis></term>
-<listitem>
-<para>
-Begin a new
-data element. The type is one of the following:
-<variablelist>
-
-<varlistentry>
-<term>record</term>
-<listitem>
-<para>
-Begin a new record. The followingparameter should be the
-name of the schema that describes the structure of the record, eg.
-<literal remap="tt">gils</literal> or <literal remap="tt">wais</literal> (see below). The <literal remap="tt">begin record</literal> call should
-precede
-any other use of the <emphasis remap="bf">begin</emphasis> statement.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>element</term>
-<listitem>
-<para>
-Begin a new tagged element. The parameter is the
-name of the tag. If the tag is not matched anywhere in the tagsets
-referenced by the current schema, it is treated as a local string
-tag.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>variant</term>
-<listitem>
-<para>
-Begin a new node in a variant tree. The parameters are
-<emphasis remap="it">class type value</emphasis>.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>data</term>
-<listitem>
-<para>
-Create a data element. The concatenated arguments make
-up the value of the data element. The option <literal remap="tt">-text</literal> signals that
-the layout (whitespace) of the data should be retained for
-transmission. The option <literal remap="tt">-element</literal> <emphasis remap="it">tag</emphasis> wraps the data up in
-the <emphasis remap="it">tag</emphasis>. The use of the <literal remap="tt">-element</literal> option is equivalent to
-preceding the command with a <emphasis remap="bf">begin element</emphasis> command, and following
-it with the <emphasis remap="bf">end</emphasis> command.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>end <emphasis remap="it">[type]</emphasis></term>
-<listitem>
-<para>
-Close a tagged element. If no parameter is given,
-the last element on the stack is terminated. The first parameter, if
-any, is a type name, similar to the <emphasis remap="bf">begin</emphasis> statement. For the
-<emphasis remap="bf">element</emphasis> type, a tag name can be provided to terminate a specific tag.
-</para>
-</listitem>
-</varlistentry>
-</variablelist>
-</para>
-
-<para>
-The following input filter reads a Usenet news file, producing a
-record in the WAIS schema. Note that the body of a news posting is
-separated from the list of headers by a blank line (or rather a
-sequence of two newline characters.
-</para>
-
-<para>
-
-<screen>
-BEGIN { begin record wais }
-
-/^From:/ BODY /$/ { data -element name $1 }
-/^Subject:/ BODY /$/ { data -element title $1 }
-/^Date:/ BODY /$/ { data -element lastModified $1 }
-/\n\n/ BODY END {
- begin element bodyOfDisplay
- begin variant body iana "text/plain"
- data -text $1
- end record
- }
-</screen>
-
-</para>
-
-<para>
-If Zebra is compiled with support for Tcl (Tool Command Language)
-enabled, the statements described above are supplemented with a complete
-scripting environment, including control structures (conditional
-expressions and loop constructs), and powerful string manipulation
-mechanisms for modifying the elements of a record. Tcl is a popular
-scripting environment, with several tutorials available both online
-and in hardcopy.
-</para>
-
-<para>
-<emphasis remap="it">NOTE: Tcl support is not currently available, but will be
-included with one of the next alpha or beta releases.</emphasis>
-</para>
-
-<para>
-<emphasis remap="it">NOTE: Variant support is not currently available in the input
-filter, but will be included with one of the next alpha or beta
-releases.</emphasis>
-</para>
-
-</sect2>
-
-</sect1>
-
-<sect1 id="internal-representation">
-<title>Internal Representation</title>
-
-<para>
-When records are manipulated by the system, they're represented in a
-tree-structure, with data elements at the leaf nodes, and tags or
-variant components at the non-leaf nodes. The root-node identifies the
-schema that lends context to the tagging and structuring of the
-record. Imagine a simple record, consisting of a 'title' element and
-an 'author' element:
-</para>
-
-<para>
-
-<screen>
- TITLE "Zen and the Art of Motorcycle Maintenance"
-ROOT
- AUTHOR "Robert Pirsig"
-</screen>
-
-</para>
-
-<para>
-A slightly more complex record would have the author element consist
-of two elements, a surname and a first name:
-</para>
-
-<para>
-
-<screen>
- TITLE "Zen and the Art of Motorcycle Maintenance"
-ROOT
- FIRST-NAME "Robert"
- AUTHOR
- SURNAME "Pirsig"
-</screen>
-
-</para>
-
-<para>
-The root of the record will refer to the record schema that describes
-the structuring of this particular record. The schema defines the
-element tags (TITLE, FIRST-NAME, etc.) that may occur in the record, as
-well as the structuring (SURNAME should appear below AUTHOR, etc.). In
-addition, the schema establishes element set names that are used by
-the client to request a subset of the elements of a given record. The
-schema may also establish rules for converting the record to a
-different schema, by stating, for each element, a mapping to a
-different tag path.
-</para>
-
-<sect2>
-<title>Tagged Elements</title>
-
-<para>
-A data element is characterized by its tag, and its position in the
-structure of the record. For instance, while the tag "telephone
-number" may be used different places in a record, we may need to
-distinguish between these occurrences, both for searching and
-presentation purposes. For instance, while the phone numbers for the
-"customer" and the "service provider" are both
-representatives for the same type of resource (a telephone number), it
-is essential that they be kept separate. The record schema provides
-the structure of the record, and names each data element (defined by
-the sequence of tags - the tag path - by which the element can be
-reached from the root of the record).
-</para>
-
-</sect2>
-
-<sect2>
-<title>Variants</title>
-
-<para>
-The children of a tag node may be either more tag nodes, a data node
-(possibly accompanied by tag nodes),
-or a tree of variant nodes. The children of variant nodes are either
-more variant nodes or a data node (possibly accompanied by more
-variant nodes). Each leaf node, which is normally a
-data node, corresponds to a <emphasis remap="it">variant form</emphasis> of the tagged element
-identified by the tag which parents the variant tree. The following
-title element occurs in two different languages:
-</para>
-
-<para>
-
-<screen>
- VARIANT LANG=ENG "War and Peace"
-TITLE
- VARIANT LANG=DAN "Krig og Fred"
-</screen>
-
-</para>
-
-<para>
-Which of the two elements are transmitted to the client by the server
-depends on the specifications provided by the client, if any.
-</para>
-
-<para>
-In practice, each variant node is associated with a triple of class,
-type, value, corresponding to the variant mechanism of Z39.50.
-</para>
-
-</sect2>
-
-<sect2>
-<title>Data Elements</title>
-
-<para>
-Data nodes have no children (they are always leaf nodes in the record
-tree).
-</para>
-
-<para>
-<emphasis remap="it">NOTE: Documentation needs extension here about types of nodes - numerical,
-textual, etc., plus the various types of inclusion notes.</emphasis>
-</para>
-
-</sect2>
-
-</sect1>
-
-<sect1 id="data-model">
-<title>Configuring Your Data Model</title>
-
-<para>
-The following sections describe the configuration files that govern
-the internal management of data records. The system searches for the files
-in the directories specified by the <emphasis remap="bf">profilePath</emphasis> setting in the
-<literal remap="tt">zebra.cfg</literal> file.
-</para>
-
-<sect2>
-<title>The Abstract Syntax</title>
-
-<para>
-The abstract syntax definition (also known as an Abstract Record
-Structure, or ARS) is the focal point of the
-record schema description. For a given schema, the ABS file may state any
-or all of the following:
-</para>
-
-<para>
-
-<itemizedlist>
-<listitem>
-
-<para>
-The object identifier of the Z39.50 schema associated
-with the ARS, so that it can be referred to by the client.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-The attribute set (which can possibly be a compound of multiple
-sets) which applies in the profile. This is used when indexing and
-searching the records belonging to the given profile.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-The Tag set (again, this can consist of several different sets).
-This is used when reading the records from a file, to recognize the
-different tags, and when transmitting the record to the client -
-mapping the tags to their numerical representation, if they are
-known.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-The variant set which is used in the profile. This provides a
-vocabulary for specifying the <emphasis remap="it">forms</emphasis> of data that appear inside
-the records.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-Element set names, which are a shorthand way for the client to
-ask for a subset of the data elements contained in a record. Element
-set names, in the retrieval module, are mapped to <emphasis remap="it">element
-specifications</emphasis>, which contain information equivalent to the
-<emphasis remap="it">Espec-1</emphasis> syntax of Z39.50.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-Map tables, which may specify mappings to <emphasis remap="it">other</emphasis> database
-profiles, if desired.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-Possibly, a set of rules describing the mapping of elements to a
-MARC representation.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-A list of element descriptions (this is the actual ARS of the
-schema, in Z39.50 terms), which lists the ways in which the various
-tags can be used and organized hierarchically.
-</para>
-</listitem>
-
-</itemizedlist>
-
-</para>
-
-<para>
-Several of the entries above simply refer to other files, which
-describe the given objects.
-</para>
-
-</sect2>
-
-<sect2>
-<title>The Configuration Files</title>
-
-<para>
-This section describes the syntax and use of the various tables which
-are used by the retrieval module.
-</para>
-
-<para>
-The number of different file types may appear daunting at first, but
-each type corresponds fairly clearly to a single aspect of the Z39.50
-retrieval facilities. Further, the average database administrator,
-who is simply reusing an existing profile for which tables already
-exist, shouldn't have to worry too much about the contents of these tables.
-</para>
-
-<para>
-Generally, the files are simple ASCII files, which can be maintained
-using any text editor. Blank lines, and lines beginning with a (#) are
-ignored. Any characters on a line followed by a (#) are also ignored.
-All other
-lines contain <emphasis remap="it">directives</emphasis>, which provide some setting or value
-to the system. Generally, settings are characterized by a single
-keyword, identifying the setting, followed by a number of parameters.
-Some settings are repeatable (r), while others may occur only once in a
-file. Some settings are optional (o), whicle others again are
-mandatory (m).
-</para>
-
-</sect2>
-
-<sect2>
-<title>The Abstract Syntax (.abs) Files</title>
-
-<para>
-The name of this file type is slightly misleading in Z39.50 terms,
-since, apart from the actual abstract syntax of the profile, it also
-includes most of the other definitions that go into a database
-profile.
-</para>
-
-<para>
-When a record in the canonical, SGML-like format is read from a file
-or from the database, the first tag of the file should reference the
-profile that governs the layout of the record. If the first tag of the
-record is, say, <literal remap="tt"><gils></literal>, the system will look for the profile
-definition in the file <literal remap="tt">gils.abs</literal>. Profile definitions are cached,
-so they only have to be read once during the lifespan of the current
-process.
-</para>
-
-<para>
-When writing your own input filters, the <emphasis remap="bf">record-begin</emphasis> command
-introduces the profile, and should always be called first thing when
-introducing a new record.
-</para>
-
-<para>
-The file may contain the following directives:
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>name <emphasis remap="it">symbolic-name</emphasis></term>
-<listitem>
-<para>
-(m) This provides a shorthand name or
-description for the profile. Mostly useful for diagnostic purposes.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>reference <emphasis remap="it">OID-name</emphasis></term>
-<listitem>
-<para>
-(m) The reference name of the OID for
-the profile. The reference names can be found in the <emphasis remap="bf">util</emphasis>
-module of <emphasis remap="bf">YAZ</emphasis>.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>attset <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-(m) The attribute set that is used for
-indexing and searching records belonging to this profile.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>tagset <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-(o) The tag set (if any) that describe
-that fields of the records.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>varset <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-(o) The variant set used in the profile.
-</para>
-</listitem>
-</varlistentry>
-<varlistentry>
-<term>maptab <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-(o,r) This points to a
-conversion table that might be used if the client asks for the record
-in a different schema from the native one.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>marc <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-(o) Points to a file containing parameters
-for representing the record contents in the ISO2709 syntax. Read the
-description of the MARC representation facility below.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>esetname <emphasis remap="it">name filename</emphasis></term>
-<listitem>
-<para>
-(o,r) Associates the
-given element set name with an element selection file. If an (@) is
-given in place of the filename, this corresponds to a null mapping for
-the given element set name.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>any <emphasis remap="it">tags</emphasis></term>
-<listitem>
-<para>
-(o) This directive specifies a list of
-attributes which should be appended to the attribute list given for each
-element. The effect is to make every single element in the abstract
-syntax searchable by way of the given attributes. This directive
-provides an efficient way of supporting free-text searching across all
-elements. However, it does increase the size of the index
-significantly. The attributes can be qualified with a structure, as in
-the <emphasis remap="bf">elm</emphasis> directive below.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>elm <emphasis remap="it">path name attributes</emphasis></term>
-<listitem>
-<para>
-(o,r) Adds an element
-to the abstract record syntax of the schema. The <emphasis remap="it">path</emphasis> follows the
-syntax which is suggested by the Z39.50 document - that is, a sequence
-of tags separated by slashes (/). Each tag is given as a
-comma-separated pair of tag type and -value surrounded by parenthesis.
-The <emphasis remap="it">name</emphasis> is the name of the element, and the <emphasis remap="it">attributes</emphasis>
-specifies which attributes to use when indexing the element in a
-comma-separated list. A ! in
-place of the attribute name is equivalent to specifying an attribute
-name identical to the element name. A - in place of the attribute name
-specifies that no indexing is to take place for the given element. The
-attributes can be qualified with <emphasis remap="it">field types</emphasis> to specify which
-character set should govern the indexing procedure for that field. The
-same data element may be indexed into several different fields, using
-different character set definitions. See the section
-<xref linkend="field-structure-and-character-sets"/>.
-The default field type is "w" for
-<emphasis remap="it">word</emphasis>.
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-<para>
-<emphasis remap="it">NOTE: The mechanism for controlling indexing is not adequate for
-complex databases, and will probably be moved into a separate
-configuration table eventually.</emphasis>
-</para>
-
-<para>
-The following is an excerpt from the abstract syntax file for the GILS
-profile.
-</para>
-
-<para>
-
-<screen>
-name gils
-reference GILS-schema
-attset gils.att
-tagset gils.tag
-varset var1.var
-
-maptab gils-usmarc.map
-
-# Element set names
-
-esetname VARIANT gils-variant.est # for WAIS-compliance
-esetname B gils-b.est
-esetname G gils-g.est
-esetname F @
-
-elm (1,10) rank -
-elm (1,12) url -
-elm (1,14) localControlNumber Local-number
-elm (1,16) dateOfLastModification Date/time-last-modified
-elm (2,1) title w:!,p:!
-elm (4,1) controlIdentifier Identifier-standard
-elm (2,6) abstract Abstract
-elm (4,51) purpose !
-elm (4,52) originator -
-elm (4,53) accessConstraints !
-elm (4,54) useConstraints !
-elm (4,70) availability -
-elm (4,70)/(4,90) distributor -
-elm (4,70)/(4,90)/(2,7) distributorName !
-elm (4,70)/(4,90)/(2,10 distributorOrganization !
-elm (4,70)/(4,90)/(4,2) distributorStreetAddress !
-elm (4,70)/(4,90)/(4,3) distributorCity !
-</screen>
-
-</para>
-
-</sect2>
-
-<sect2 id="attset-files">
-<title>The Attribute Set (.att) Files</title>
-
-<para>
-This file type describes the <emphasis remap="bf">Use</emphasis> elements of an attribute set.
-It contains the following directives.
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>name <emphasis remap="it">symbolic-name</emphasis></term>
-<listitem>
-<para>
-(m) This provides a shorthand name or
-description for the attribute set. Mostly useful for diagnostic purposes.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>reference <emphasis remap="it">OID-name</emphasis></term>
-<listitem>
-<para>
-(m) The reference name of the OID for
-the attribute set. The reference names can be found in the <emphasis remap="bf">util</emphasis>
-module of <emphasis remap="bf">YAZ</emphasis>.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>ordinal <emphasis remap="it">integer</emphasis></term>
-<listitem>
-<para>
-(m) This value will be used to represent the
-attribute set in the index. Care should be taken that each attribute
-set has a unique ordinal value.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>include <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-(o,r) This directive is used to
-include another attribute set as a part of the current one. This is
-used when a new attribute set is defined as an extension to another
-set. For instance, many new attribute sets are defined as extensions
-to the <emphasis remap="bf">bib-1</emphasis> set. This is an important feature of the retrieval
-system of Z39.50, as it ensures the highest possible level of
-interoperability, as those access points of your database which are
-derived from the external set (say, bib-1) can be used even by clients
-who are unaware of the new set.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>att <emphasis remap="it">att-value att-name [local-value]</emphasis></term>
-<listitem>
-<para>
-(o,r) This
-repeatable directive introduces a new attribute to the set. The
-attribute value is stored in the index (unless a <emphasis remap="it">local-value</emphasis> is
-given, in which case this is stored). The name is used to refer to the
-attribute from the <emphasis remap="it">abstract syntax</emphasis>.
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-<para>
-This is an excerpt from the GILS attribute set definition. Notice how
-the file describing the <emphasis remap="it">bib-1</emphasis> attribute set is referenced.
-</para>
-
-<para>
-
-<screen>
-name gils
-reference GILS-attset
-include bib1.att
-ordinal 2
-
-att 2001 distributorName
-att 2002 indextermsControlled
-att 2003 purpose
-att 2004 accessConstraints
-att 2005 useConstraints
-</screen>
-
-</para>
-
-</sect2>
-
-<sect2>
-<title>The Tag Set (.tag) Files</title>
-
-<para>
-This file type defines the tagset of the profile, possibly by
-referencing other tag sets (most tag sets, for instance, will include
-tagsetG and tagsetM from the Z39.50 specification. The file may
-contain the following directives.
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>name <emphasis remap="it">symbolic-name</emphasis></term>
-<listitem>
-<para>
-(m) This provides a shorthand name or
-description for the tag set. Mostly useful for diagnostic purposes.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>reference <emphasis remap="it">OID-name</emphasis></term>
-<listitem>
-<para>
-(o) The reference name of the OID for
-the tag set. The reference names can be found in the <emphasis remap="bf">util</emphasis>
-module of <emphasis remap="bf">YAZ</emphasis>. The directive is optional, since not all tag sets
-are registered outside of their schema.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>type <emphasis remap="it">integer</emphasis></term>
-<listitem>
-<para>
-(m) The type number of the tagset within the schema
-profile (note: this specification really should belong to the .abs
-file. This will be fixed in a future release).
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>include <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-(o,r) This directive is used
-to include the definitions of other tag sets into the current one.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>tag <emphasis remap="it">number names type</emphasis></term>
-<listitem>
-<para>
-(o,r) Introduces a new
-tag to the set. The <emphasis remap="it">number</emphasis> is the tag number as used in the protocol
-(there is currently no mechanism for specifying string tags at this
-point, but this would be quick work to add). The <emphasis remap="it">names</emphasis> parameter
-is a list of names by which the tag should be recognized in the input
-file format. The names should be separated by slashes (/). The
-<emphasis remap="it">type</emphasis> is th recommended datatype of the tag. It should be one of
-the following:
-
-<itemizedlist>
-<listitem>
-
-<para>
-structured
-</para>
-</listitem>
-<listitem>
-
-<para>
-string
-</para>
-</listitem>
-<listitem>
-
-<para>
-numeric
-</para>
-</listitem>
-<listitem>
-
-<para>
-bool
-</para>
-</listitem>
-<listitem>
-
-<para>
-oid
-</para>
-</listitem>
-<listitem>
-
-<para>
-generalizedtime
-</para>
-</listitem>
-<listitem>
-
-<para>
-intunit
-</para>
-</listitem>
-<listitem>
-
-<para>
-int
-</para>
-</listitem>
-<listitem>
-
-<para>
-octetstring
-</para>
-</listitem>
-<listitem>
-
-<para>
-null
-</para>
-</listitem>
-
-</itemizedlist>
-
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-<para>
-The following is an excerpt from the TagsetG definition file.
-</para>
-
-<para>
-
-<screen>
-name tagsetg
-reference TagsetG
-type 2
-
-tag 1 title string
-tag 2 author string
-tag 3 publicationPlace string
-tag 4 publicationDate string
-tag 5 documentId string
-tag 6 abstract string
-tag 7 name string
-tag 8 date generalizedtime
-tag 9 bodyOfDisplay string
-tag 10 organization string
-</screen>
-
-</para>
-
-</sect2>
-
-<sect2 id="variant-set">
-<title>The Variant Set (.var) Files</title>
-
-<para>
-The variant set file is a straightforward representation of the
-variant set definitions associated with the protocol. At present, only
-the <emphasis remap="it">Variant-1</emphasis> set is known.
-</para>
-
-<para>
-These are the directives allowed in the file.
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>name <emphasis remap="it">symbolic-name</emphasis></term>
-<listitem>
-<para>
-(m) This provides a shorthand name or
-description for the variant set. Mostly useful for diagnostic purposes.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>reference <emphasis remap="it">OID-name</emphasis></term>
-<listitem>
-<para>
-(o) The reference name of the OID for
-the variant set, if one is required. The reference names can be found
-in the <emphasis remap="bf">util</emphasis> module of <emphasis remap="bf">YAZ</emphasis>.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>class <emphasis remap="it">integer class-name</emphasis></term>
-<listitem>
-<para>
-(m,r) Introduces a new
-class to the variant set.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>type <emphasis remap="it">integer type-name datatype</emphasis></term>
-<listitem>
-<para>
-(m,r) Addes a
-new type to the current class (the one introduced by the most recent
-<emphasis remap="bf">class</emphasis> directive). The type names belong to the same name space as
-the one used in the tag set definition file.
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-<para>
-The following is an excerpt from the file describing the variant set
-<emphasis remap="it">Variant-1</emphasis>.
-</para>
-
-<para>
-
-<screen>
-name variant-1
-reference Variant-1
-
-class 1 variantId
-
- type 1 variantId octetstring
-
-class 2 body
-
- type 1 iana string
- type 2 z39.50 string
- type 3 other string
-</screen>
-
-</para>
-
-</sect2>
-
-<sect2>
-<title>The Element Set (.est) Files</title>
-
-<para>
-The element set specification files describe a selection of a subset
-of the elements of a database record. The element selection mechanism
-is equivalent to the one supplied by the <emphasis remap="it">Espec-1</emphasis> syntax of the
-Z39.50 specification. In fact, the internal representation of an
-element set specification is identical to the <emphasis remap="it">Espec-1</emphasis> structure,
-and we'll refer you to the description of that structure for most of
-the detailed semantics of the directives below.
-</para>
-
-<para>
-<emphasis remap="it">NOTE: Not all of the Espec-1 functionality has been implemented yet.
-The fields that are mentioned below all work as expected, unless
-otherwise is noted.</emphasis>
-</para>
-
-<para>
-The directives available in the element set file are as follows:
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>defaultVariantSetId <emphasis remap="it">OID-name</emphasis></term>
-<listitem>
-<para>
-(o) If variants are used in
-the following, this should provide the name of the variantset used
-(it's not currently possible to specify a different set in the
-individual variant request). In almost all cases (certainly all
-profiles known to us), the name <literal remap="tt">Variant-1</literal> should be given here.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>defaultVariantRequest <emphasis remap="it">variant-request</emphasis></term>
-<listitem>
-<para>
-(o) This directive
-provides a default variant request for
-use when the individual element requests (see below) do not contain a
-variant request. Variant requests consist of a blank-separated list of
-variant components. A variant compont is a comma-separated,
-parenthesized triple of variant class, type, and value (the two former
-values being represented as integers). The value can currently only be
-entered as a string (this will change to depend on the definition of
-the variant in question). The special value (@) is interpreted as a
-null value, however.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>simpleElement <emphasis remap="it">path ['variant' variant-request]</emphasis></term>
-<listitem>
-<para>
-(o,r) This corresponds to a simple element request in <emphasis remap="it">Espec-1</emphasis>. The
-path consists of a sequence of tag-selectors, where each of these can
-consist of either:
-</para>
-
-<para>
-
-<itemizedlist>
-<listitem>
-
-<para>
-A simple tag, consisting of a comma-separated type-value pair in
-parenthesis, possibly followed by a colon (:) followed by an
-occurrences-specification (see below). The tag-value can be a number
-or a string. If the first character is an apostrophe ('), this forces
-the value to be interpreted as a string, even if it appears to be numerical.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-A WildThing, represented as a question mark (?), possibly
-followed by a colon (:) followed by an occurrences specification (see
-below).
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-A WildPath, represented as an asterisk (*). Note that the last
-element of the path should not be a wildPath (wildpaths don't work in
-this version).
-</para>
-</listitem>
-
-</itemizedlist>
-
-</para>
-
-<para>
-The occurrences-specification can be either the string <literal remap="tt">all</literal>, the
-string <literal remap="tt">last</literal>, or an explicit value-range. The value-range is
-represented as an integer (the starting point), possibly followed by a
-plus (+) and a second integer (the number of elements, default being
-one).
-</para>
-
-<para>
-The variant-request has the same syntax as the defaultVariantRequest
-above. Note that it may sometimes be useful to give an empty variant
-request, simply to disable the default for a specific set of fields
-(we aren't certain if this is proper <emphasis remap="it">Espec-1</emphasis>, but it works in
-this implementation).
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-<para>
-The following is an example of an element specification belonging to
-the GILS profile.
-</para>
-
-<para>
-
-<screen>
-simpleelement (1,10)
-simpleelement (1,12)
-simpleelement (2,1)
-simpleelement (1,14)
-simpleelement (4,1)
-simpleelement (4,52)
-</screen>
-
-</para>
-
-</sect2>
-
-<sect2 id="schema-mapping">
-<title>The Schema Mapping (.map) Files</title>
-
-<para>
-Sometimes, the client might want to receive a database record in
-a schema that differs from the native schema of the record. For
-instance, a client might only know how to process WAIS records, while
-the database record is represented in a more specific schema, such as
-GILS. In this module, a mapping of data to one of the MARC formats is
-also thought of as a schema mapping (mapping the elements of the
-record into fields consistent with the given MARC specification, prior
-to actually converting the data to the ISO2709). This use of the
-object identifier for USMARC as a schema identifier represents an
-overloading of the OID which might not be entirely proper. However,
-it represents the dual role of schema and record syntax which
-is assumed by the MARC family in Z39.50.
-</para>
-
-<para>
-<emphasis remap="it">NOTE: The schema-mapping functions are so far limited to a
-straightforward mapping of elements. This should be extended with
-mechanisms for conversions of the element contents, and conditional
-mappings of elements based on the record contents.</emphasis>
-</para>
-
-<para>
-These are the directives of the schema mapping file format:
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>targetName <emphasis remap="it">name</emphasis></term>
-<listitem>
-<para>
-(m) A symbolic name for the target schema
-of the table. Useful mostly for diagnostic purposes.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>targetRef <emphasis remap="it">OID-name</emphasis></term>
-<listitem>
-<para>
-(m) An OID name for the target schema.
-This is used, for instance, by a server receiving a request to present
-a record in a different schema from the native one. The name, again,
-is found in the <emphasis remap="bf">oid</emphasis> module of <emphasis remap="bf">YAZ</emphasis>.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>map <emphasis remap="it">element-name target-path</emphasis></term>
-<listitem>
-<para>
-(o,r) Adds
-an element mapping rule to the table.
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-</sect2>
-
-<sect2>
-<title>The MARC (ISO2709) Representation (.mar) Files</title>
-
-<para>
-This file provides rules for representing a record in the ISO2709
-format. The rules pertain mostly to the values of the constant-length
-header of the record.
-</para>
-
-<para>
-<emphasis remap="it">NOTE: This will be described better. We're in the process of
-re-evaluating and most likely changing the way that MARC records are
-handled by the system.</emphasis>
-</para>
-
-</sect2>
-
-<sect2 id="field-structure-and-character-sets">
-<title>Field Structure and Character Sets
-</title>
-
-<para>
-In order to provide a flexible approach to national character set
-handling, Zebra allows the administrator to configure the set up the
-system to handle any 8-bit character set — including sets that
-require multi-octet diacritics or other multi-octet characters. The
-definition of a character set includes a specification of the
-permissible values, their sort order (this affects the display in the
-SCAN function), and relationships between upper- and lowercase
-characters. Finally, the definition includes the specification of
-space characters for the set.
-</para>
-
-<para>
-The operator can define different character sets for different fields,
-typical examples being standard text fields, numerical fields, and
-special-purpose fields such as WWW-style linkages (URx).
-</para>
-
-<para>
-The field types, and hence character sets, are associated with data
-elements by the .abs files (see above). The file <literal remap="tt">default.idx</literal>
-provides the association between field type codes (as used in the .abs
-files) and the character map files (with the .chr suffix). The format
-of the .idx file is as follows
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>index <emphasis remap="it">field type code</emphasis></term>
-<listitem>
-<para>
-This directive introduces a new
-search index code. The argument is a one-character code to be used in the
-.abs files to select this particular index type. An index, roughly,
-corresponds to a particular structure attribute during search. Refer
-to section <xref linkend="search"/>.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>sort <emphasis remap="it">field code type</emphasis></term>
-<listitem>
-<para>
-This directive introduces a
-sort index. The argument is a one-character code to be used in the
-.abs fie to select this particular index type. The corresponding
-use attribute must be used in the sort request to refer to this
-particular sort index. The corresponding character map (see below)
-is used in the sort process.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>completeness <emphasis remap="it">boolean</emphasis></term>
-<listitem>
-<para>
-This directive enables or disables
-complete field indexing. The value of the <emphasis remap="it">boolean</emphasis> should be 0
-(disable) or 1. If completeness is enabled, the index entry will
-contain the complete contents of the field (up to a limit), with words
-(non-space characters) separated by single space characters
-(normalized to " " on display). When completeness is
-disabled, each word is indexed as a separate entry. Complete subfield
-indexing is most useful for fields which are typically browsed (eg.
-titles, authors, or subjects), or instances where a match on a
-complete subfield is essential (eg. exact title searching). For fields
-where completeness is disabled, the search engine will interpret a
-search containing space characters as a word proximity search.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>charmap <emphasis remap="it">filename</emphasis></term>
-<listitem>
-<para>
-This is the filename of the character
-map to be used for this index for field type.
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-<para>
-The contents of the character map files are structured as follows:
-</para>
-
-<para>
-<variablelist>
-
-<varlistentry>
-<term>lowercase <emphasis remap="it">value-set</emphasis></term>
-<listitem>
-<para>
-This directive introduces the basic
-value set of the field type. The format is an ordered list (without
-spaces) of the characters which may occur in "words" of
-the given type. The order of the entries in the list determines the
-sort order of the index. In addition to single characters, the
-following combinations are legal:
-</para>
-
-<para>
-
-<itemizedlist>
-<listitem>
-
-<para>
-Backslashes may be used to introduce three-digit octal, or
-two-digit hex representations of single characters (preceded by <literal remap="tt">x</literal>).
-In addition, the combinations
-\\, \\r, \\n, \\t, \\s (space — remember that real space-characters
-may ot occur in the value definition), and \\ are recognised,
-with their usual interpretation.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-Curly braces {} may be used to enclose ranges of single
-characters (possibly using the escape convention described in the
-preceding point), eg. {a-z} to entroduce the standard range of ASCII
-characters. Note that the interpretation of such a range depends on
-the concrete representation in your local, physical character set.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-paranthesises () may be used to enclose multi-byte characters -
-eg. diacritics or special national combinations (eg. Spanish
-"ll"). When found in the input stream (or a search term),
-these characters are viewed and sorted as a single character, with a
-sorting value depending on the position of the group in the value
-statement.
-</para>
-</listitem>
-
-</itemizedlist>
-
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>uppercase <emphasis remap="it">value-set</emphasis></term>
-<listitem>
-<para>
-This directive introduces the
-upper-case equivalencis to the value set (if any). The number and
-order of the entries in the list should be the same as in the
-<literal remap="tt">lowercase</literal> directive.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>space <emphasis remap="it">value-set</emphasis></term>
-<listitem>
-<para>
-This directive introduces the character
-which separate words in the input stream. Depending on the
-completeness mode of the field in question, these characters either
-terminate an index entry, or delimit individual "words" in
-the input stream. The order of the elements is not significant —
-otherwise the representation is the same as for the <literal remap="tt">upercase</literal> and
-<literal remap="tt">lowercase</literal> directives.
-</para>
-</listitem></varlistentry>
-<varlistentry>
-<term>map <emphasis remap="it">value-set</emphasis> <emphasis remap="it">target</emphasis></term>
-<listitem>
-<para>
-This directive introduces a
-mapping between each of the members of the value-set on the left to
-the character on the right. The character on the right must occur in
-the value set (the <literal remap="tt">lowercase</literal> directive) of the character set, but
-it may be a paranthesis-enclosed multi-octet character. This directive
-may be used to map diacritics to their base characters, or to map
-HTML-style character-representations to their natural form, etc.
-</para>
-</listitem></varlistentry>
-</variablelist>
-</para>
-
-</sect2>
-
-</sect1>
-
-<sect1 id="formats">
-<title>Exchange Formats</title>
-
-<para>
-Converting records from the internal structure to en exchange format
-is largely an automatic process. Currently, the following exchange
-formats are supported:
-</para>
-
-<para>
-
-<itemizedlist>
-<listitem>
-
-<para>
-GRS-1. The internal representation is based on GRS-1, so the
-conversion here is straightforward. The system will create
-applied variant and supported variant lists as required, if a record
-contains variant information.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-SUTRS. Again, the mapping is fairly straighforward. Indentation
-is used to show the hierarchical structure of the record. All
-"GRS" type records support both the GRS-1 and SUTRS
-representations.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-ISO2709-based formats (USMARC, etc.). Only records with a
-two-level structure (corresponding to fields and subfields) can be
-directly mapped to ISO2709. For records with a different structuring
-(eg., GILS), the representation in a structure like USMARC involves a
-schema-mapping (see section <xref linkend="schema-mapping"/>), to an
-"implied" USMARC schema (implied,
-because there is no formal schema which specifies the use of the
-USMARC fields outside of ISO2709). The resultant, two-level record is
-then mapped directly from the internal representation to ISO2709. See
-the GILS schema definition files for a detailed example of this
-approach.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-Explain. This representation is only available for records
-belonging to the Explain schema.
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-Summary. This ASN-1 based structure is only available for records
-belonging to the Summary schema - or schema which provide a mapping
-to this schema (see the description of the schema mapping facility
-above).
-
-</para>
-</listitem>
-<listitem>
-
-<para>
-SOIF. Support for this syntax is experimental, and is currently
-keyed to a private Index Data OID (1.2.840.10003.5.1000.81.2). All
-abstract syntaxes can be mapped to the SOIF format, although nested
-elements are represented by concatenation of the tag names at each
-level.
-
-</para>
-</listitem>
-
-</itemizedlist>
-
-</para>
-
-</sect1>
-
-</chapter>
+ <!-- Keep this comment at the end of the file
+ Local variables:
+ mode: sgml
+ sgml-omittag:t
+ sgml-shorttag:t
+ sgml-minimize-attributes:nil
+ sgml-always-quote-attributes:t
+ sgml-indent-step:1
+ sgml-indent-data:t
+ sgml-parent-document: "zebra.xml"
+ sgml-local-catalogs: nil
+ sgml-namecase-general:t
+ End:
+ -->
projects / idzebra-moved-to-github.git / blobdiff