<!doctype linuxdoc system>
<!--
- $Id: zebra.sgml,v 1.13 1996-01-03 16:21:58 quinn Exp $
+ $Id: zebra.sgml,v 1.40 1998-02-10 12:03:05 adam Exp $
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<article>
<title>Zebra Server - Administrators's Guide and Reference
-<author>Index Data, <tt/info@index.ping.dk/
-<date>$Revision: 1.13 $
+<author><htmlurl url="http://www.indexdata.dk/" name="Index Data">,
+<tt><htmlurl url="mailto:info@indexdata.dk" name="info@indexdata.dk"></>
+<date>$Revision: 1.40 $
<abstract>
The Zebra information server combines a versatile fielded/free-text
search engine with a Z39.50-1995 frontend to provide a powerful and flexible
functionality that you need.
If you find the software interesting, you should join the support
-mailing-list by sending Email to <tt/zebra-request@index.ping.dk/.
+mailing-list by sending email to <tt/zebra-request@indexdata.dk/.
<sect1>Features
<p>
-This is a listof some of the most important features of the
+This is a list of some of the most important features of the
system.
<itemize>
well as variant forms of data.
<item>
+Supports random storage formats. A system of input filters driven by
+regular expressions allows you to easily process most ASCII-based
+data formats. SGML, ISO2709 (MARC), and raw text are also supported.
+
+<item>
Supports boolean queries as well as relevance-ranking (free-text)
searching. Right truncation and masking in terms are supported, as
well as full regular expressions.
schema on the fly.
<item>
+Supports approximate matching in registers (ie. spelling mistakes,
+etc).
+
+</itemize>
+
+<p>
Protocol support:
<itemize>
<item>
-Protocol facilities: Init, Search, Retrieve, Browse.
+Protocol facilities: Init, Search, Retrieve, Browse and Sort.
<item>
Piggy-backed presents are honored in the search-request.
server can utilise a plug-in XTI/mOSI implementation (not included) to
provide SR services over an OSI stack, as well as Z39.50 over TCP/IP.
-</itemize>
+<item>
+Zebra runs on most Unix-like systems as well as Windows NT - a binary
+distribution for Windows NT is forthcoming - so far, the installation
+requires MSVC++ to compile the system (we use version 5.0).
</itemize>
<sect1>Future Work
<p>
-This is an alfa-release of the software, to allow you to look at
-it - try it out, and assess whether it can be of use to you. We expect
-this version to be followed by a succession of beta-releases until we
-arrive at a stable first version.
+This is a beta-release of the software, to allow you to look at
+it - try it out, and assess whether it can be of use to you.
These are some of the plans that we have for the software in the near
and far future, approximately ordered after their relative importance.
<itemize>
<item>
-*Allow the system to handle other input formats. Specifically
-MARC records and general, structured ASCII records (such as mail/news
-files) parameterized by regular expressions.
-
-<item>
-*Complete the support for variants. Finalize support for the WAIS
-retrieval methodology.
+*Complete the support for variants.
<item>
*Finalize the data element <it/include/ facility to support multimedia
data elements in records.
<item>
-*Port the system to Windows NT.
-
-<item>
-Add index and data compression to save disk space.
-
-<item>
Add more sophisticated relevance ranking mechanisms. Add support for soundex
-and stemming. Add relevance feedback support.
+and stemming. Add relevance <it/feedback/ support.
<item>
-Add Explain support.
+Complete EXPLAIN support.
<item>
Add support for very large records by implementing segmentation and/or
Support the Item Update extended service of the protocol.
<item>
-The Zebra search engine supports approximate string matching in the
-index. We'd like to find a way to support and control this from RPN.
-
-<item>
We want to add a management system that allows you to
control your databases and configuration tables from a graphical
interface. We'll probably use Tcl/Tk to stay platform-independent.
neat, you're welcome to drop us a line saying that, too. You'll find
contact info at the end of this file.
-<sect>Getting Started
-
<sect>Compiling the software
<p>
-Zebra uses the YAZ package to implement Z39.50, so you
-have to compile YAZ before going further. Specifically, Zebra uses
-the YAZ header files in <tt>yaz/include/..</tt> and its public library
-<tt>yaz/lib/libyaz.a</tt>.
-
-As with YAZ, an ANSI C compiler is required in order to compile the Zebra
+An ANSI C compiler is required to compile the Zebra
server system — <tt/gcc/ works fine if your own system doesn't
provide an adequate compiler.
-Unpack the Zebra software. You might put Zebra in the same directory level
-as YAZ, for example if YAZ is placed in ..<tt>/src/yaz-xxx</tt>, then
-Zebra is placed in ..<tt>/src/zebra-yyy</tt>.
-
-Edit the top-level <tt>Makefile</tt> in the Zebra directory in which
-you specify the location of YAZ by setting make variables.
-The <tt>OSILIB</tt> should be empty if YAZ wasn't compiled with
-MOSI support. Some systems, such as Solaris, have separate socket
-libraries and for those systems you need to specify the
-<tt>NETLIB</tt> variable.
+Unpack the distribution archive. In some cases, you may want to edit
+the top-level <tt/Makefile/, eg. to select a different C compiler, or
+to specify machine-specific libraries in the <bf/ELIBS/ variable.
When you are done editing the <tt>Makefile</tt> type:
<tscreen><verb>
<tag><tt>zebraidx</tt></tag> The administrative tool for the search index.
</descrip>
-<sect>Quick Start
-
+<sect>Quick Start
<p>
-This section will get you started quickly! We will try to index a few sample
-GILS records that are included with the Zebra distribution. Go to the
-<tt>test</tt> subdirectory. There you will find a configuration
+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
+<tt>test/gils</tt> subdirectory of the distribution archive. There you will
+find a configuration
file named <tt>zebra.cfg</tt> with the following contents:
<tscreen><verb>
# Where are the YAZ tables located.
-profilePath: /usr/local/yaz
+profilePath: ../../../yaz/tab ../../tab
# Files that describe the attribute sets supported.
attset: bib1.att
</verb></tscreen>
Now, edit the file and set <tt>profilePath</tt> to the path of the
-YAZ profile tables (sub directory <tt>tab</tt> of YAZ).
+YAZ profile tables (sub directory <tt>tab</tt> of the YAZ distribution
+archive).
The 48 test records are located in the sub directory <tt>records</tt>.
To index these, type:
<tscreen><verb>
-$ ../index/zebraidx -t grs update records
+$ ../../index/zebraidx -t grs.sgml update records
</verb></tscreen>
In the command above the option <tt>-t</tt> specified the record
-type — in this case <tt>grs</tt>. The word <tt>update</tt> followed
+type — in this case <tt>grs.sgml</tt>. The word <tt>update</tt> followed
by a directory root updates all files below that directory node.
If your indexing command was successful, you are now ready to
fire up a server. To start a server on port 2100, type:
<tscreen><verb>
-$ ../index/zebrasrv tcp:@:2100
+$ ../../index/zebrasrv tcp:@:2100
</verb></tscreen>
-The Zebra index that you've just made has one database called Default. It will
-return either USMARC, GRS-1, or SUTRS depending on what your client asks
+The Zebra index that you have just created has a single database
+named <tt/Default/. 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.
To test the server, you can use any Z39.50 client (1992 or later). For
Z>show 1
Z>format grs-1
Z>show 1
+Z>elements B
+Z>show 1
</verb></tscreen>
-If you've made it this far, there's a reasonably good chance that
+<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.</it>
+
+If you've made it this far, there's a good chance that
you've got through the compilation OK.
-<sect><heading><label id="administrating">Administrating Zebra</>
+<sect>Administrating Zebra<label id="administrating">
<p>
Unlike many simpler retrieval systems, Zebra supports safe, incremental
The configuration file includes specifications on how to index
various kinds of records and where the other configuration files
are located. <tt>zebrasrv</tt> and <tt>zebraidx</tt> <em>must</em>
-be run in the same directory where the configuration file if you do
-not indicate the location of the configuration file by option
+be run in the directory where the configuration file lives unless you
+indicate the location of the configuration file by option
<tt>-c</tt>.
-<sect1><heading><label id="record-types">Record Types</>
+<sect1>Record Types<label id="record-types">
<p>
-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 only supports SGML-like, structured records and unstructured text
-records.
+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 <tt>-t</tt> or specify a
<tt>recordType</tt> setting in the configuration file.
-<sect1><heading><label id="configuration-file">The Zebra Configuration File</>
+<sect1>The Zebra Configuration File<label id="configuration-file">
<p>
The Zebra configuration file, read by <tt>zebraidx</tt> and
<tt>zebrasrv</tt> defaults to <tt>zebra.cfg</tt> unless specified
Parameter names and values are seperated by colons in the file. Lines
starting with a hash sign (<tt/#/) are treated as comments.
-If you manage different sets of records that each share common
-caracteristics, you can organize the configuration settings for each
+If you manage different sets of records that share common
+characteristics, you can organize the configuration settings for each
type into &dquot;groups&dquot;.
When <tt>zebraidx</tt> is run and you wish to address a given group
-you specify that group with the <tt>-g</tt> option. In this case
+you specify the group name with the <tt>-g</tt> option. In this case
settings that have the group name as their prefix will be used
-by <tt>zebraidx</tt> and not default values. The default values have no prefix.
+by <tt>zebraidx</tt>. If no <tt/-g/ option is specified, the settings
+with no prefix are used.
-The group is written before the option itself, separated by a dot (.).
-For instance, to set the record type for group <tt/public/ to <tt/grs/
-(the common format for structured records)
-you would write:
+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 <tt/public/ to <tt/grs.sgml/ (the SGML-like format for structured
+records) you would write:
<tscreen><verb>
-public.recordType: grs
+public.recordType: grs.sgml
</verb></tscreen>
To set the default value of the record type to <tt/text/ write:
recordType: text
</verb></tscreen>
-The configuration settings are summarized below. They will be
+The available configuration settings are summarized below. They will be
explained further in the following sections.
<descrip>
-<tag><it>group</it>recordType<it>name</it></tag>
+<tag><it>group</it>.recordType[<it>.name</it>]</tag>
Specifies how records with the file extension <it>name</it> should
be handled by the indexer. This option may also be specified
as a command line option (<tt>-t</tt>). Note that if you do not
- specify a <it/name/, the setting applies to all files.
-<tag><it>group</it>recordId</tag>
- Specifies how the record is to be identified when updated.
-<tag><it>group</it>database</tag>
+ specify a <it/name/, the setting applies to all files. In general,
+ the record type specifier consists of the elements (each
+ element separated by dot), <it>fundamental-type</it>,
+ <it>file-read-type</it> and arguments. Currently, two
+ fundamental types exist, <tt>text</tt> and <tt>grs</tt>.
+ <tag><it>group</it>.recordId</tag>
+ Specifies how the records are to be identified when updated. See
+section <ref id="locating-records" name="Locating Records">.
+<tag><it>group</it>.database</tag>
Specifies the Z39.50 database name.
-<tag><it>group</it>storeKeys</tag>
+<tag><it>group</it>.storeKeys</tag>
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).
-<tag><it>group</it>storeData</tag>
+ should be 0 (default), to save register space. See section
+<ref id="file-ids" name="Indexing With File Record IDs">.
+<tag><it>group</it>.storeData</tag>
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).
<tag>register</tag>
- Specifies the location of the various files that Zebra uses to represent
- your system.
-<tag>tempSetPath</tag>
+ Specifies the location of the various register files that Zebra uses
+ to represent your databases. See section
+<ref id="register-location" name="Register Location">.
+<tag>shadow</tag>
+ Enables the <it/safe update/ facility of Zebra, and tells the system
+ where to place the required, temporary files. See section
+<ref id="shadow-registers" name="Safe Updating - Using Shadow Registers">.
+<tag>lockDir</tag>
+ Directory in which various lock files are stored.
+<tag>keyTmpDir</tag>
+ Directory in which temporary files used during zebraidx' update
+ phase are stored.
+<tag>setTmpDir</tag>
Specifies the directory that the server uses for temporary result sets.
If not specified <tt>/tmp</tt> will be used.
<tag>profilePath</tag>
- Specifies the location of profile specification paths.
+ Specifies the location of profile specification files.
<tag>attset</tag>
Specifies the filename(s) of attribute set files for use in
searching. At least the Bib-1 set should be loaded (<tt/bib1.att/).
- The <tt/profilePath/ setting is used to search for attribute set
- files.
+ The <tt/profilePath/ setting is used to look for the specified files.
+ See section <ref id="attset-files" name="The Attribute Set Files">
+<tag>memMax</tag>
+ Specifies size of internal memory to use for the zebraidx program. The
+ amount is given in megabytes - default is 4 (4 MB).
</descrip>
-
-<sect1>Locating Records
+<sect1>Locating Records<label id="locating-records">
<p>
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 <tt/zebraidx/.
-
-If your input files are temporary - for example if you retrieve
-your records from an outside source, or if they where temporarily mounted on a CD-ROM,
+ran <tt/zebraidx/. 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 <tt/zebraidx/ again, the client will receive a diagnostic
+message.
+
+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 <tt>storedata</tt> setting. When
+you specify 1 (true) in the <tt>storeData</tt> setting. When
the Z39.50 server retrieves the records they will be read from the
internal file structures of the system.
<sect1>Indexing with no Record IDs (Simple Indexing)
<p>
-If you have a set of records that you <em/never/ wish to delete
-or modify you may find &dquot;indexing without records IDs&dquot; convenient.
+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.
-To use this method, you simply don't provide the <tt>recordId</tt> entry
+To use this method, you simply omit the <tt>recordId</tt> entry
for the group of files that you index. To add a set of records you use
<tt>zebraidx</tt> with the <tt>update</tt> command. The
-<tt>update</tt> command will always add all of the records to the index
-because Zebra doesn't know how to match the new set of records with
-existing records.
+<tt>update</tt> 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.
Consider a system in which you have a group of text files called
<tt>simple</tt>. That group of records should belong to a Z39.50 database
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.
-<sect1>Indexing with File Record IDs
+<sect1>Indexing with File Record IDs<label id="file-ids">
<p>
-If you have a set of external records that you wish to index you may
-use the file key feature of the Zebra system. In short, the file key
-methodology uses the paths of the files containing records as their
-unique identifiers. To perform indexing of a directory with file keys,
-again, you specify the top-level directory after the <tt>update</tt>
-command. The command will recursively traverse the directories and
-compare each with whatever have been indexed before in the 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 insertionm, the index
-is also modified; if a file has been removed since the last visit, it
-is deleted from the index.
-
-The resulting system is easy to administer. To delete a record
-you simply have to delete the corresponding file (say, with the
-<tt/rm/ command).
-To force update of a given file, you may use the <tt>touch</tt>
-command. And to add files create new files (or directories with files).
-For your changes to take effect in the register you must run <tt>zebraidx</tt> with
-the same directory root again.
-
-To use this method, you must specify <tt>file</tt> as the value
-of <tt>recordId</tt> in the configuration file. In addition, you
-should set <tt>storeKeys</tt> to <tt>1</tt>, since the Zebra
-indexer must save additional information about the keys to each record in order to
-modify the indices correctly at a later time.
-
-For example, to update group <tt>esdd</tt> records below
-<tt>/home/grs</tt> you could type:
+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 <it/file ID/ 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
+<tt>update</tt> 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.
+
+The resulting system is easy to administrate. To delete a record you
+simply have to delete the corresponding file (say, with the <tt/rm/
+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
+<tt>zebraidx update</tt> 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
+<it/safe update/ facility (see below), you never have to take your
+server offline for maintenance or register updating purposes.
+
+To enable indexing with pathname IDs, you must specify <tt>file</tt> as
+the value of <tt>recordId</tt> in the configuration file. In addition,
+you should set <tt>storeKeys</tt> to <tt>1</tt>, 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.
+
+For example, to update records of group <tt>esdd</tt> located below
+<tt>/data1/records/</tt> you should type:
<tscreen><verb>
-$ zebraidx -g esdd update /home/grs
+$ zebraidx -g esdd update /data1/records
</verb></tscreen>
The corresponding configuration file includes:
<tscreen><verb>
esdd.recordId: file
-esdd.recordType: grs
+esdd.recordType: grs.sgml
esdd.storeKeys: 1
</verb></tscreen>
You cannot explicitly delete records when using this method (using the
<bf/delete/ command to <tt/zebraidx/. Instead
-you have to delete the files from the file system (or remove them)
-and then run <tt>zebraidx</tt> with the <bf/update/ command again.
+you have to delete the files from the file system (or move them to a
+different location)
+and then run <tt>zebraidx</tt> with the <bf/update/ command.
<sect1>Indexing with General Record IDs
<p>
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 associates an ID with
-each record, this method is convenient. For example, the record 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 this
-field to determine the identity of the record.
+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.
As before, the record ID is defined by the <tt>recordId</tt> setting
in the configuration file. The value of the record ID specification
by single- or double quotes.
</descrip>
-The sample GILS records that come with the Zebra distribution contain a
+For instance, the sample GILS records that come with the Zebra
+distribution contain a
unique ID
in the Control-Identifier field. This field is mapped to the Bib-1
use attribute 1007. To use this field as a record id, specify
gils.recordId: $type (1,1007)
</verb></tscreen>
-As for the file record id case described in the previous section
+(see section <ref id="data-model" name="Configuring Your Data Model">
+for details of how the mapping between elements of your records and
+searchable attributes is established).
+
+As for the file record ID case described in the previous section,
updating your system is simply a matter of running <tt>zebraidx</tt>
with the <tt>update</tt> command. However, the update with general
keys is considerably slower than with file record IDs, since all files
-visited must be (re)read to find their IDs.
+visited must be (re)read to discover their IDs.
-You may have noticed that when using the general record IDs
+As you might expect, when using the general record IDs
method, you can only add or modify existing records with the <tt>update</tt>
command. If you wish to delete records, you must use the,
<tt>delete</tt> command, with a directory as a parameter.
This will remove all records that match the files below that root
directory.
-<sect1><heading><label id="register-location">Register Location</>
+<sect1>Register Location<label id="register-location">
<p>
Normally, the index files that form dictionaries, inverted
files, record info, etc., are stored in the directory where you run
<tt>zebraidx</tt>. If you wish to store these, possibly large, files
somewhere else, you must add the <tt>register</tt> entry to the
-configuration file. Furthermore, the Zebra system allows its file
+<tt/zebra.cfg/ file. Furthermore, the Zebra system allows its file
structures to
-span multiple file systems, which is useful if a very large number of
-records are stored.
+span multiple file systems, which is useful for managing very large
+databases.
-The value <tt>register</tt> of register is a sequence of tokens.
+The value of the <tt>register</tt> setting is a sequence of tokens.
Each token takes the form:
<tscreen>
<em>dir</em><tt>:</tt><em>size</em>.
The <em>size</em> is an integer followed by a qualifier
code, <tt>M</tt> for megabytes, <tt>k</tt> for kilobytes.
-For instance, if you have two spare disks :) and the first disk is mounted
+For instance, if you have allocated two disks for your register, and
+the first disk is mounted
on <tt>/d1</tt> and has 200 Mb of free space and the
second, mounted on <tt>/d2</tt> has 300 Mb, you could
put this entry in your configuration file:
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 use the free space. In a large production system,
+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.
-<sect1><heading><label id="shadow-registers">Safe Updating - Using Shadow Registers</>
+<sect1>Safe Updating - Using Shadow Registers<label id="shadow-registers">
<sect2>Description
<p>
-The Zebra server supports updating of the index structures. That is,
-you can add records to 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.
+The Zebra server supports <it/updating/ 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.
You can solve these problems by enabling the shadow register system in
Zebra. During the updating procedure, <tt/zebraidx/ will temporarily
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 process is interrupted at any point during the
+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
the <tt/register/ entry (see section <ref name="Register Location"
id="register-location">). The location of the shadow area should be
<it/different/ from the location of the main register area (if you
-have specified one - remember that the default register area is the
+have specified one - remember that if you provide no <tt/register/
+setting, the default register area is the
working directory of the server and indexing processes).
The following excerpt from a <tt/zebra.cfg/ 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.
+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.
<tscreen><verb>
register: /d1:500M
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
<it/large/ and <it/modest/ very loosely here, since every
-application's perception of size is different). To update the system
+application will have a different perception of size). To update the system
without the use of the the shadow files, simply run <tt/zebraidx/ with
the <tt/-n/ option (note that you do not have to execute the
<bf/commit/ command of <tt/zebraidx/ when you temporarily disable the
<bf/Options/
<descrip>
<tag>-t <it/type/</tag>Update all files as <it/type/. Currently, the
-types supported are <tt/text/ and <tt/grs/<it/.filter/. If no
-<it/filter/ is provided for the GRS (General Record Structure) type,
+types supported are <tt/text/ and <tt/grs/<it/.subtype/. If no
+<it/subtype/ is provided for the GRS (General Record Structure) type,
the canonical input format is assumed (see section <ref
id="local-representation" name="Local Representation">). Generally, it
is probably advisable to specify the record types in the
-<tt/zebra.cfg/ file (see section <ref id="record-types" name="Record Types">).
+<tt/zebra.cfg/ file (see section <ref id="record-types" name="Record
+Types">), to avoid confusion at subsequent updates.
<tag>-c <it/config-file/</tag>Read the configuration file
<it/config-file/ instead of <tt/zebra.cfg/.
with the database name <it/database/ for access through the Z39.50
server.
-<tag>-d <it/mbytes/</tag>Use <it/mbytes/ of megabytes before flushing
+<tag>-m <it/mbytes/</tag>Use <it/mbytes/ of megabytes before flushing
keys to background storage. This setting affects performance when
updating large databases.
(see section <ref id="shadow-registers" name="Robust Updating - Using
Shadow Registers">).
+<tag>-s</tag>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.
+
+<tag>-V</tag>Show Zebra version.
+
<tag>-v <it/level/</tag>Set the log level to <it/level/. <it/level/
should be one of <tt/none/, <tt/debug/, and <tt/all/.
</descrip>
-<sect>Running the Z39.50 Server (zebrasrv)
+<sect>The Z39.50 Server
+
+<sect1>Running the Z39.50 Server (zebrasrv)
<p>
<bf/Syntax/
zebrasrv [options] [listener-address ...]
</verb></tscreen>
+<bf/Options/
<descrip>
<tag>-a <it/APDU file/</tag> Specify a file for dumping PDUs (for diagnostic purposes).
The special name &dquot;-&dquot; sends output to <tt/stderr/.
-<tag>-c <it/config-file/</tag> Read configuration information from <it/config-file/. The default configuration is <tt/./zebra.cfg/.
+<tag>-c <it/config-file/</tag> Read configuration information from <it/config-file/. The default configuration is <tt>./zebra.cfg</tt>.
<tag/-S/Don't fork on connection requests. This can be useful for
symbolic-level debugging. The server can only accept a single
given <it/username/. 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.
+
+<tag>-w <it/working-directory/</tag>Change working directory.
+
+<tag>-i</tag>Run under the Internet superserver, <tt/inetd/. Make
+sure you use the logfile option <tt/-l/ in conjunction with this
+mode and specify the <tt/-l/ option before any other options.
+
+<tag>-t <it/timeout/</tag>Set the idle session timeout (default 60 minutes).
+
+<tag>-k <it/kilobytes/</tag>Set the (approximate) maximum size of
+present response messages. Default is 1024 Kb (1 Mb).
</descrip>
A <it/listener-address/ consists of a transport mode followed by a
The default behavior for <tt/zebrasrv/ is to establish a single TCP/IP
listener, for the Z39.50 protocol, on port 9999.
+<sect1>Z39.50 Protocol Support and Behavior
+
+<sect2>Initialization
+
+<p>
+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.
+
+<sect2>Search<label id="search">
+
+<p>
+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.
+
+The server has full support for piggy-backed present requests (see
+also the following section).
+
+<bf/Use/ attributes are interpreted according to the attribute sets which
+have been loaded in the <tt/zebra.cfg/ file, and are matched against
+specific fields as specified in the <tt/.abs/ file which describes the
+profile of the records which have been loaded. If no <bf/Use/
+attribute is provided, a default of Bib-1 <bf/Any/ is assumed.
+
+If a <bf/Structure/ attribute of <bf/Phrase/ is used in conjunction with a
+<bf/Completeness/ attribute of <bf/Complete (Sub)field/, the term is
+matched against the contents of the phrase (long word) register, if one
+exists for the given <bf/Use/ attribute.
+A phrase register is created for those fields in the <tt/.abs/
+file that contains a <tt/p/-specifier.
+
+If <bf/Structure/=<bf/Phrase/ is used in conjunction with
+<bf/Incomplete Field/ - the default value for <bf/Completeness/, 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 <tt/w/ in the <tt/.abs/ file.
+
+If the <bf/Structure/ attribute is <bf/Word List/,
+<bf/Free-form Text/, or <bf/Document Text/, 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 <tt/w/ in the <tt/.abs/ file.
+
+If the <bf/Structure/ attribute is <bf/Numeric String/ the
+term is treated as an integer. The search is performed on those
+fields that are indexed as type <tt/n/ in the <tt/.abs/ file.
+
+If the <bf/Structure/ attribute is <bf/URx/ the
+term is treated as a URX (URL) entity. The search is performed on those
+fields that are indexed as type <tt/u/ in the <tt/.abs/ file.
+
+If the <bf/Structure/ attribute is <bf/Local Number/ the
+term is treated as native Zebra Record Identifier.
+
+If the <bf/Relation/ attribute is <bf/Equals/ (default), the term is
+matched in a normal fashion (modulo truncation and processing of
+individual words, if required). If <bf/Relation/ is <bf/Less Than/,
+<bf/Less Than or Equal/, <bf/Greater than/, or <bf/Greater than or
+Equal/, the term is assumed to be numerical, and a standard regular
+expression is constructed to match the given expression. If
+<bf/Relation/ is <bf/Relevance/, the standard natural-language query
+processor is invoked.
+
+For the <bf/Truncation/ attribute, <bf/No Truncation/ is the default.
+<bf/Left Truncation/ is not supported. <bf/Process #/ is supported, as
+is <bf/Regxp-1/. <bf/Regxp-2/ 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.
+
+<sect3>Regular expressions
+<p>
+
+Each term in a query is interpreted as a regular expression if
+the truncation value is either <bf/Regxp-1/ (102) or <bf/Regxp-2/ (103).
+Both query types follow the same syntax with the operands:
+<descrip>
+<tag/x/ Matches the character <it/x/.
+<tag/./ Matches any character.
+<tag><tt/[/..<tt/]/</tag> Matches the set of characters specified;
+ such as <tt/[abc]/ or <tt/[a-c]/.
+</descrip>
+and the operators:
+<descrip>
+<tag/x*/ Matches <it/x/ zero or more times. Priority: high.
+<tag/x+/ Matches <it/x/ one or more times. Priority: high.
+<tag/x?/ Matches <it/x/ once or twice. Priority: high.
+<tag/xy/ Matches <it/x/, then <it/y/. Priority: medium.
+<tag/x|y/ Matches either <it/x/ or <it/y/. Priority: low.
+</descrip>
+The order of evaluation may be changed by using parentheses.
+
+If the first character of the <bf/Regxp-2/ query is a plus character
+(<tt/+/) 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.
+
+Since the plus operator is normally a suffix operator the addition to
+the query syntax doesn't violate the syntax for standard regular
+expressions.
+
+<sect3>Query examples
+<p>
+
+Phrase search for <bf/information retrieval/ in the title-register:
+<verb>
+ @attr 1=4 "information retrieval"
+</verb>
+
+Ranked search for the same thing:
+<verb>
+ @attr 1=4 @attr 2=102 "Information retrieval"
+</verb>
+
+Phrase search with a regular expression:
+<verb>
+ @attr 1=4 @attr 5=102 "informat.* retrieval"
+</verb>
+
+Ranked search with a regular expression:
+<verb>
+ @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval"
+</verb>
+
+In the GILS schema (<tt/gils.abs/), the west-bounding-coordinate is
+indexed as type <tt/n/, and is therefore searched by specifying
+<bf/structure/=<bf/Numeric String/.
+To match all those records with west-bounding-coordinate greater
+than -114 we use the following query:
+<verb>
+ @attr 4=109 @attr 2=5 @attr gils 1=2038 -114
+</verb>
+
+<sect2>Present
+<p>
+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.
+
+<sect2>Scan
+
+<p>
+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.
+
+<sect2>Sort
+
+<p>
+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.
+
+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.
+
+<sect2>Close
+
+<p>
+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.
+
<sect>The Record Model
<p>
-The Zebra system is designed to span a wide range of data management
+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 <it/record schema/ which lends context to the data elements of the
Although it may be wise to use only a single schema within
one database, the system poses no such restrictions.
+The record model described in this chapter applies to the fundamental,
+structured
+record type <tt>grs</tt> as introduced in
+section <ref id="record-types" name="Record Types">.
+
Records pass through three different states during processing in the
system.
<itemize>
-<item>When records are first entered into the system, they are represented
+<item>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 a flexible scripting language (Tcl). The input filter
+expressions and possibly augmented by a flexible scripting language (Tcl). The input filter
produces as output an internal representation:
<item>When records are processed by the system, they are represented
over the network - according to the Z39.50 standard.
</itemize>
-<sect1><heading><label id="local-representation">Local Representation</>
+<sect1>Local Representation<label id="local-representation">
<p>
As mentioned earlier, Zebra places few restrictions on the type of
process takes place whenever the record is accessed - for indexing and
retrieval.
+<p>
+The RecordType parameter in the <tt/zebra.cfg/ file, or the <tt/-t/
+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 <bf/text/ 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
+&dquot;grs&dquot; keyboard, separated by &dquot;.&dquot; characters.
+
+Three basic subtypes to the <bf/grs/ type are currently available:
+
+<descrip>
+<tag>grs.sgml</tag>This is the canonical input format —
+described below. It is a simple SGML-like syntax.
+
+<tag>grs.regx.<it/filter/</tag>This enables a user-supplied input
+filter. The mechanisms of these filters are described below.
+
+<tag>grs.marc.<it/abstract syntax/</tag>This allows Zebra to read
+records in the ISO2709 (MARC) encoding standard. In this case, the
+last paramemeter <it/abstract syntax/ names the .abs file (see below)
+which describes the specific MARC structure of the input record as
+well as the indexing rules.
+</descrip>
+
<sect2>Canonical Input Format
<p>
spectrum of structure and flexibility in the system. In Zebra, this
canonical format is an &dquot;SGML-like&dquot; syntax.
+To use the canonical format specify <tt>grs.sgml</tt> as the record
+type,
+
Consider a record describing an information resource (such a record is
sometimes known as a <it/locator record/). It might contain a field
describing the distributor of the information resource, which might in
</verb></tscreen>
<it>NOTE: The indentation used above is used to illustrate how Zebra
-interprets the expression. The indentation, in itself, has no
+interprets the markup. The indentation, in itself, has no
significance to the parser for the canonical input format, which
-ignores all whitespace.</it>
+discards superfluous whitespace.</it>
The keywords surrounded by <...> are <it/tags/, while the
sections of text in between are the <it/data elements/. 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 &etago;, and containing the same symbolic tag-name as
-the corresponding opening tag. The general closing tag - &etago;> -
+beginning with <tt/&etago;/, and containing the same symbolic tag-name as
+the corresponding opening tag. The general closing tag - <tt/&etago;>/ -
terminates the element started by the last opening tag. The
structuring of elements is significant. The element <bf/Telephone/,
for instance, may be indexed and presented to the client differently,
depending on whether it appears inside the <bf/Distributor/ element,
-or some other data element.
+or some other, structured data element such a <bf/Supplier/ element.
<sect3>Record Root
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):
+the Z39.50 profile, however - it merely attempts to match up elements
+of a local representation with the given schema):
<tscreen><verb>
<gils>
Zebra allows you to provide individual data elements in a number of
<it/variant forms/. 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 is
-essentially a clean representation of the variant mechanism of
+may appear in different formats or layouts. The variant system in
+Zebra is
+essentially a representation of the variant mechanism of
Z39.50-1995.
The following is an example of a title element which occurs in two
</verb></tscreen>
Associates two variant components to the variant list for the title
-element. Given the nesting rules described above, we could write
+element.
+
+Given the nesting rules described above, we could write
<tscreen><verb>
<title>
The title element above comes in two variants. Both have the IANA body
type &dquot;text/plain&dquot;, but one is in English, and the other in
-Danish.
+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.
<sect2>Input Filters
<p>
-In order to handle general, text-based input formats, Zebra allows the
-operator to specify filters which read individual records in their native format
+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.
Input filters are ASCII files, generally with the suffix <tt/.flt/.
The system looks for the files in the directories given in the
-<bf/profilePath/ setting in the <tt/zebra.cfg/ file.
+<bf/profilePath/ setting in the <tt/zebra.cfg/ files. The record type
+for the filter is <tt>grs.regx.</tt><it>filter-filename</it>
+(fundamental type <tt>grs</tt>, file read type <tt>regx</tt>, argument
+<it>filter-filename</it>).
Generally, an input filter consists of a sequence of rules, where each
rule consists of a sequence of expressions, followed by an action. The
<tag>begin <it/type [parameter ... ]/</tag>Begin a new
data element. The type is one of the following:
<descrip>
-<tag/record/Begin a new record. The parameter should be the
+<tag/record/Begin a new record. The followingparameter should be the
name of the schema that describes the structure of the record, eg.
-<tt/gils/ or <tt/wais/. The <tt/begin record/ call should come before
-any other call to <bf/begin/.
+<tt/gils/ or <tt/wais/ (see below). The <tt/begin record/ call should
+precede
+any other use of the <bf/begin/ statement.
<tag/element/Begin a new tagged element. The parameter is the
name of the tag. If the tag is not matched anywhere in the tagsets
</descrip>
-<tag/data/Create a data element under. The concatenated arguments make
+<tag/data/Create a data element. The concatenated arguments make
up the value of the data element. The option <tt/-text/ signals that
the layout (whitespace) of the data should be retained for
transmission. The option <tt/-element/ <it/tag/ wraps the data up in
preceding the command with a <bf/begin element/ command, and following
it with the <bf/end/ command.
-<tag>end <it/[type]/</tag>Close a data element. If no parameter is given,
+<tag>end <it/[type]/</tag>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 <bf/begin/ statement. For the
<bf/element/ type, a tag name can be provided to terminate a specific tag.
</descrip>
The following input filter reads a Usenet news file, producing a
-record in the WAIS schema.
+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.
<tscreen><verb>
BEGIN { begin record wais }
and in hardcopy.
<it>NOTE: Tcl support is not currently available, but will be
-included with the next release.</it>
+included with one of the next alpha or beta releases.</it>
-<sect1><heading><label id="internal-representation">Internal Representation</>
+<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.</it>
+
+<sect1>Internal Representation<label id="internal-representation">
<p>
When records are manipulated by the system, they're represented in a
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 occur in the record, as
+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 tagging.
+different tag path.
+
+<sect2>Tagged Elements
+
+<p>
+A data element is characterized by its tag, and its position in the
+structure of the record. For instance, while the tag &dquot;telephone
+number&dquot; 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
+&dquot;customer&dquot; and the &dquot;service provider&dquot; 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).
+
+<sect2>Variants
+<p>
+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 <it/variant form/ of the tagged element
+identified by the tag which parents the variant tree. The following
+title element occurs in two different languages:
+
+<tscreen><verb>
+ VARIANT LANG=ENG "War and Peace"
+TITLE
+ VARIANT LANG=DAN "Krig og Fred"
+</verb></tscreen>
+
+Which of the two elements are transmitted to the client by the server
+depends on the specifications provided by the client, if any.
+
+In practice, each variant node is associated with a triple of class,
+type, value, corresponding to the variant mechanism of Z39.50.
+
+<sect2>Data Elements
+
+<p>
+Data nodes have no children (they are always leaf nodes in the record
+tree).
+
+<it>NOTE: Documentation needs extension here about types of nodes - numerical,
+textual, etc., plus the various types of inclusion notes.</it>
+
+<sect1>Configuring Your Data Model<label id="data-model">
+
+<p>
The following sections describe the configuration files that govern
-the internal management of records. The system searches for the files
+the internal management of data records. The system searches for the files
in the directories specified by the <bf/profilePath/ setting in the
<tt/zebra.cfg/ file.
<sect2>The Abstract Syntax
<p>
-The abstract syntax definition (ARS) is the focal point of the
-record schema description. For a given schema, it may state any
+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:
<itemize>
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
+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.
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 followed by a (#) are also ignored. All other
-lines contain <it/directives/, which establish some setting or value
+ignored. Any characters on a line followed by a (#) are also ignored.
+All other
+lines contain <it/directives/, 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
record is, say, <tt><gils></tt>, the system will look for the profile
definition in the file <tt/gils.abs/. Profile definitions are cached,
so they only have to be read once during the lifespan of the current
-process.
+process.
When writing your own input filters, the <bf/record-begin/ command
introduces the profile, and should always be called first thing when
given in place of the filename, this corresponds to a null mapping for
the given element set name.
-<tag>elm <it/path name attribute/</tag> (o,r) Adds an element
+<tag>any <it/tags/</tag> (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 <bf/elm/ directive below.
+
+<tag>elm <it/path name attributes/</tag> (o,r) Adds an element
to the abstract record syntax of the schema. The <it/path/ 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 <it/name/ is the name of the element, and the <it/attribute/
-specifies what attribute to use when indexing the element. A ! in
+The <it/name/ is the name of the element, and the <it/attributes/
+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.
+specifies that no indexing is to take place for the given element. The
+attributes can be qualified with <it/field types/ 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
+<ref id="field structure and character sets"
+name="Field Structure and Character Sets">.
+The default field type is &dquot;w&dquot; for
+<it/word/.
</descrip>
<it>
elm (1,12) url -
elm (1,14) localControlNumber Local-number
elm (1,16) dateOfLastModification Date/time-last-modified
-elm (2,1) Title !
+elm (2,1) Title w:!,p:!
elm (4,1) controlIdentifier Identifier-standard
elm (2,6) abstract Abstract
elm (4,51) purpose !
elm (4,70)/(4,90)/(4,3) distributorCity !
</verb></tscreen>
-<sect2>The Attribute Set (.att) Files
+<sect2>The Attribute Set (.att) Files<label id="attset-files">
<p>
This file type describes the <bf/Use/ elements of an attribute set.
module of <bf/YAZ/. The directive is optional, since not all tag sets
are registered outside of their schema.
-<tag>type <it/integer/</tag> (m) The type number of the tag within the schema
-profile.
+<tag>type <it/integer/</tag> (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).
<tag>include <it/filename/</tag> (o,r) This directive is used
to include the definitions of other tag sets into the current one.
tag 10 organization string
</verb></tscreen>
-<sect2><heading><label id="variant-set">The Variant Set (.var) Files</>
+<sect2>The Variant Set (.var) Files<label id="variant-set">
<p>
The variant set file is a straightforward representation of the
simpleelement (4,52)
</verb></tscreen>
-<sect2><heading><label id="schema-mapping">The Schema Mapping (.map) Files</>
+<sect2>The Schema Mapping (.map) Files<label id="schema-mapping">
<p>
Sometimes, the client might want to receive a database record in
re-evaluating and most likely changing the way that MARC records are
handled by the system.</it>
+<sect2>Field Structure and Character Sets
+<label id="field structure and character sets">
+
+<p>
+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.
+
+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).
+
+The field types, and hence character sets, are associated with data
+elements by the .abs files (see above). The file <tt/default.idx/
+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
+
+<descrip>
+<tag>index <it/field type code/</tag>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 <ref id="search" name="Search">.
+
+<tag>sort <it/field code type/</tag>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.
+
+<tag>completeness <it/boolean/</tag>This directive enables or disables
+complete field indexing. The value of the <it/boolean/ 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 &dquot; &dquot; 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.
+
+<tag>charmap <it/filename/</tag> This is the filename of the character
+map to be used for this index for field type.
+</descrip>
+
+The contents of the character map files are structured as follows:
+
+<descrip>
+<tag>lowercase <it/value-set/</tag>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 &dquot;words&dquot; 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:
+
+<itemize>
+<item>Backslashes may be used to introduce three-digit octal, or
+two-digit hex representations of single characters (preceded by <tt/x/).
+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.
+
+<item>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.
+
+<item>Paranthesises () may be used to enclose multi-byte characters -
+eg. diacritics or special national combinations (eg. Spanish
+&dquot;ll&dquot;). 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.
+</itemize>
+
+<tag>uppercase <it/value-set/</tag>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
+<tt/lowercase/ directive.
+
+<tag>space <it/value-set/</tag>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 &dquot;words&dquot; in
+the input stream. The order of the elements is not significant —
+otherwise the representation is the same as for the <tt/upercase/ and
+<tt/lowercase/ directives.
+
+<tag>map <it/value-set/ <it/target/</tag>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 <tt/lowercase/ 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.
+</descrip>
+
<sect1>Exchange Formats
<p>
contains variant information.
<item>SUTRS. Again, the mapping is fairly straighforward. Indentation
-is used to show the hierarchical structure of the record.
+is used to show the hierarchical structure of the record. All
+&dquot;GRS&dquot; type records support both the GRS-1 and SUTRS
+representations.
<item>ISO2709-based formats (USMARC, etc.). Only records with a
two-level structure (corresponding to fields and subfields) can be
<item>Explain. This representation is only available for records
belonging to the Explain schema.
+<item>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).
+
+<item>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.
+
</itemize>
<sect>License
<p>
-Copyright © 1995, Index Data.
+Copyright © 1995-1998 Index Data.
All rights reserved.
purpose, our consulting services and expert knowledge of the software
is available to you at favorable rates.
-<tscreen>
-Index Data&nl
-Ryesgade 3&nl
-DK-2200 København N&nl
-</tscreen>
+<tscreen><verb>
+Index Data
+Ryesgade 3
+DK-2200 Copenhagen N
+</verb></tscreen>
<p>
<tscreen><verb>
Phone: +45 3536 3672
Fax : +45 3536 0449
-Email: info@index.ping.dk
+Email: info@indexdata.dk
</verb></tscreen>
The <it>Random House College Dictionary</it>, 1975 edition
projects / idzebra-moved-to-github.git / blobdiff