X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=doc%2Fadministration.xml;h=dca0506281701ef62e740cbf9d123f62badd5762;hb=7c3a0352f0492609a3b6b26b63a72b0b2d207aab;hp=fd1e8f41513e9c9917d014f9500ef9397f681325;hpb=dd8372e3f27c68a0410f13044dd184ccde8ca243;p=idzebra-moved-to-github.git diff --git a/doc/administration.xml b/doc/administration.xml index fd1e8f4..dca0506 100644 --- a/doc/administration.xml +++ b/doc/administration.xml @@ -1,120 +1,13 @@ - - Quick Start - - - 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 - test/gils subdirectory of the distribution archive. - There you will find a configuration - file named zebra.cfg with the following contents: - - - # Where are the YAZ tables located. - profilePath: ../../../yaz/tab ../../tab - - # Files that describe the attribute sets supported. - attset: bib1.att - attset: gils.att - - - - - Now, edit the file and set profilePath to the path of the - YAZ profile tables (sub directory tab of the YAZ - distribution archive). - - - - The 48 test records are located in the sub directory - records. To index these, type: - - - $ ../../index/zebraidx -t grs.sgml update records - - - - - In the command above the option -t specified the record - type — in this case grs.sgml. - The word update 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: - - - $ ../../index/zebrasrv tcp:@:2100 - - - - - - The Zebra index that you have just created has a single database - named 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 instance, you can use the demo client that comes with YAZ: Just - cd to the client subdirectory of the YAZ distribution - and type: - - - - $ ./yaz-client tcp:localhost:2100 - - - - - When the client has connected, you can type: - - - - - - Z> find surficial - Z> show 1 - - - - - The default retrieval syntax for the client is USMARC. To try other - formats for the same record, try: - - - - Z>format sutrs - Z>show 1 - Z>format grs-1 - Z>show 1 - Z>elements B - Z>show 1 - - - - - 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. - - - - If you've made it this far, there's a good chance that - you've got through the compilation OK. - - - - + Administrating Zebra - + + Unlike many simpler retrieval systems, Zebra supports safe, incremental updates to an existing index. @@ -141,9 +34,9 @@ Modify - 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. + 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. @@ -161,8 +54,8 @@ 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). + indexer must be able to generate a unique key that identifies the record + in question (more on this below). @@ -174,8 +67,9 @@ 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 zebra.cfg. + set of index files and a global configuration file. + The name of the configuration file defaults to + zebra.cfg. The configuration file includes specifications on how to index various kinds of records and where the other configuration files are located. zebrasrv and zebraidx @@ -191,7 +85,7 @@ 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: + 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 -t or specify a @@ -211,8 +105,8 @@ 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 (#) are + parameter names and values are separated by colons in the file. Lines + starting with a hash sign (#) are treated as comments. @@ -258,13 +152,18 @@ explained further in the following sections. + + group - .recordType[.name] + .recordType[.name]: + type @@ -282,36 +181,42 @@ - group.recordId + group.recordId: + record-id-spec Specifies how the records are to be identified when updated. See - section . + . - group.database + group.database: + database Specifies the Z39.50 database name. + - group.storeKeys + group.storeKeys: + boolean 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 - . + should be 0 (default), to save register space. + + See . - group.storeData + group.storeData: + boolean Specifies whether the records should be stored internally @@ -324,28 +229,28 @@ - register + + register: register-location Specifies the location of the various register files that Zebra uses - to represent your databases. See section - . + to represent your databases. + See . - shadow + shadow: register-location Enables the safe update facility of Zebra, and tells the system where to place the required, temporary files. - See section - . + See . - lockDir + lockDir: directory Directory in which various lock files are stored. @@ -353,16 +258,16 @@ - keyTmpDir + keyTmpDir: directory - Directory in which temporary files used during zebraidx' update + Directory in which temporary files used during zebraidx's update phase are stored. - setTmpDir + setTmpDir: directory Specifies the directory that the server uses for temporary result sets. @@ -371,15 +276,17 @@ - profilePath + profilePath: path - Specifies the location of profile specification files. + Specifies a path of profile specification files. + The path is composed of one or more directories separated by + colon. Similar to PATH for UNIX systems. - attset + attset: filename Specifies the filename(s) of attribute set files for use in @@ -387,19 +294,68 @@ (bib1.att). The profilePath setting is used to look for the specified files. - See section + See + + + + + memMax: size + + + Specifies size 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. + + + + + tempfiles: Yes/Auto/No + + + 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 memMax + megabytes of memory. This should be good for most uses. + + + + + + root: dir + + + 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 + zebra.cfg is located. + + + @@ -409,14 +365,15 @@ Locating Records - The default behaviour of the Zebra system is to reference the + The default behavior of the Zebra system is to reference the records from their original location, i.e. where they were found when you ran 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 zebraidx again, the client - will receive a diagnostic message. + running zebraidx again, the server will return + diagnostic number 14 (``System error in presenting records'') to + the client. @@ -461,7 +418,7 @@ - profilePath: /usr/local/yaz + profilePath: /usr/local/idzebra/tab attset: bib1.att simple.recordType: text simple.database: textbase @@ -509,7 +466,7 @@ 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 safe update - facility (see below), you never have to take your server offline for + facility (see below), you never have to take your server off-line for maintenance or register updating purposes. @@ -519,9 +476,13 @@ in the configuration file. In addition, you should set storeKeys to 1, 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. + in order to modify the indexes correctly at a later time. + + For example, to update records of group esdd located below @@ -557,13 +518,14 @@ and then run zebraidx with the update command. + Indexing with General Record IDs - When using this method you construct an (almost) arbritrary, internal + 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 @@ -672,7 +634,7 @@ - (see section + (see for details of how the mapping between elements of your records and searchable attributes is established). @@ -726,19 +688,22 @@ each directory in the order specified and use the next specified directories as needed. The size is an integer followed by a qualifier - code, M for megabytes, + code, + b for bytes, k for kilobytes. + M for megabytes, + G for gigabytes. For instance, if you have allocated two disks for your register, and the first disk is mounted - on /d1 and has 200 Mb of free space and the - second, mounted on /d2 has 300 Mb, you could + on /d1 and has 2GB of free space and the + second, mounted on /d2 has 3.6 GB, you could put this entry in your configuration file: - register: /d1:200M /d2:300M + register: /d1:2G /d2:3600M @@ -749,7 +714,7 @@ 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. + file system exclusively to the Zebra register files. @@ -821,7 +786,7 @@ zebra.cfg file. The syntax of the shadow entry is exactly the same as for the register entry - (see section ). + (see ). The location of the shadow area should be different from the location of the main register area (if you have specified one - remember that if you provide no @@ -855,14 +820,13 @@ 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: - $ zebraidx update /d1/records update /d2/more-records commit + $ zebraidx update /d1/records + $ zebraidx commit @@ -874,7 +838,7 @@ - $ zebraidx -g books update /d1/records update /d2/more-records + $ zebraidx -g books update /d1/records /d2/more-records $ zebraidx -g fun update /d3/fun-records $ zebraidx commit @@ -924,2550 +888,6 @@ - - - Running the Maintenance Interface (zebraidx) - - - The following is a complete reference to the command line interface to - the zebraidx application. - - - - Syntax - - - $ zebraidx [options] command [directory] ... - - - Options: - - - - -t type - - - Update all files as type. Currently, the - types supported are text and - grs.subtype. - If no subtype is provided for the GRS - (General Record Structure) type, the canonical input format - is assumed (see section ). - Generally, it is probably advisable to specify the record types - in the zebra.cfg file (see section - ), to avoid confusion at - subsequent updates. - - - - - -c config-file - - - Read the configuration file - config-file instead of - zebra.cfg. - - - - - -g group - - - Update the files according to the group - settings for group (see section - ). - - - - - -d database - - - The records located should be associated with the database name - database for access through the Z39.50 server. - - - - - -m mbytes - - - Use mbytes of megabytes before flushing - keys to background storage. This setting affects performance when - updating large databases. - - - - - -n - - - Disable the use of shadow registers for this operation - (see section ). - - - - - -s - - - 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. - - - - - -V - - - Show Zebra version. - - - - - -v level - - - Set the log level to level. - level should be one of - none, debug, and - all. - - - - - - - - Commands - - - - update directory - - - Update the register with the files contained in - directory. - If no directory is provided, a list of files is read from - stdin. - See section . - - - - - delete directory - - - Remove the records corresponding to the files found under - directory from the register. - - - - - commit - - - Write the changes resulting from the last update - commands to the register. This command is only available if the use of - shadow register files is enabled (see section - ). - - - - - - - - - - The Z39.50 Server - - - Running the Z39.50 Server (zebrasrv) - - - Syntax - - - zebrasrv [options] [listener-address ...] - - - - - - Options - - - - -a APDU file - - - Specify a file for dumping PDUs (for diagnostic purposes). - The special name "-" sends output to stderr. - - - - - -c config-file - - - Read configuration information from - config-file. - The default configuration is ./zebra.cfg. - - - - - -S - - - 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. - - - - - -s - - - Use the SR protocol. - - - - - -z - - - 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. - - - - - -l logfile - - - Specify an output file for the diagnostic messages. - The default is to write this information to stderr. - - - - - -v log-level - - - The log level. Use a comma-separated list of members of the set - {fatal,debug,warn,log,all,none}. - - - - - -u username - - - Set user ID. Sets the real UID of the server process to that of the - given 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. - - - - - -w working-directory - - - Change working directory. - - - - - -i - - - Run under the Internet superserver, inetd. - Make sure you use the logfile option -l in - conjunction with this mode and specify the -l - option before any other options. - - - - - -t timeout - - - Set the idle session timeout (default 60 minutes). - - - - - -k kilobytes - - - Set the (approximate) maximum size of - present response messages. Default is 1024 Kb (1 Mb). - - - - - - - - A listener-address consists of a transport - mode followed by a colon (:) followed by a listener address. - The transport mode is either ssl or - tcp. - - - - For TCP, an address has the form - - - - - - hostname | IP-number [: portnumber] - - - - - - The port number defaults to 210 (standard Z39.50 port). - - - - Examples - - - - - - tcp:dranet.dra.com - - ssl:secure.lib.com:3000 - - - - - - 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 port for - Z39.50, and to drop root privileges once the ports are bound, execute - the server like this (from a root shell): - - - - - - zebrasrv -u daemon tcp:@ - - - - - - You can replace daemon with another user, eg. - your own account, or a dedicated IR server account. - - - - The default behavior for zebrasrv is to establish - a single TCP/IP listener, for the Z39.50 protocol, on port 9999. - - - - - - Z39.50 Protocol Support and Behavior - - - Initialization - - - 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. - - - - - - Search - - - 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). - - - - Use attributes are interpreted according to the - attribute sets which have been loaded in the - zebra.cfg file, and are matched against specific - fields as specified in the .abs file which - describes the profile of the records which have been loaded. - If no Use attribute is provided, a default of Bib-1 Any is assumed. - - - - If a Structure attribute of - Phrase is used in conjunction with a - Completeness attribute of - Complete (Sub)field, the term is matched - against the contents of the phrase (long word) register, if one - exists for the given Use attribute. - A phrase register is created for those fields in the - .abs file that contains a - p-specifier. - - - - If Structure=Phrase is - used in conjunction with Incomplete Field - the - default value for 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 w in the .abs file. - - - - If the Structure attribute is - Word List, - Free-form Text, or - 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 w in the - .abs file. - - - - If the Structure attribute is - Numeric String the term is treated as an integer. - The search is performed on those fields that are indexed - as type n in the .abs file. - - - - If the Structure attribute is - URx the term is treated as a URX (URL) entity. - The search is performed on those fields that are indexed as type - u in the .abs file. - - - - If the Structure attribute is - Local Number the term is treated as - native Zebra Record Identifier. - - - - If the Relation attribute is - Equals (default), the term is matched - in a normal fashion (modulo truncation and processing of - individual words, if required). - If Relation is Less Than, - Less Than or Equal, - Greater than, or Greater than or - Equal, the term is assumed to be numerical, and a - standard regular expression is constructed to match the given - expression. - If Relation is Relevance, - the standard natural-language query processor is invoked. - - - - For the Truncation attribute, - No Truncation is the default. - Left Truncation is not supported. - Process # is supported, as is - Regxp-1. - 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. - - - - Regular expressions - - - Each term in a query is interpreted as a regular expression if - the truncation value is either Regxp-1 (102) - or Regxp-2 (103). - Both query types follow the same syntax with the operands: - - - - x - - - Matches the character x. - - - - - . - - - Matches any character. - - - - - [..] - - - Matches the set of characters specified; - such as [abc] or [a-c]. - - - - - and the operators: - - - - x* - - - Matches x zero or more times. Priority: high. - - - - - x+ - - - Matches x one or more times. Priority: high. - - - - - x? - - - Matches x once or twice. Priority: high. - - - - - xy - - - Matches x, then y. - Priority: medium. - - - - - x|y - - - Matches either x or y. - Priority: low. - - - - - The order of evaluation may be changed by using parentheses. - - - - If the first character of the Regxp-2 query - is a plus character (+) 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. - - - - - - Query examples - - - Phrase search for information retrieval in - the title-register: - - @attr 1=4 "information retrieval" - - - - - Ranked search for the same thing: - - @attr 1=4 @attr 2=102 "Information retrieval" - - - - - Phrase search with a regular expression: - - @attr 1=4 @attr 5=102 "informat.* retrieval" - - - - - Ranked search with a regular expression: - - @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval" - - - - - In the GILS schema (gils.abs), the - west-bounding-coordinate is indexed as type n, - and is therefore searched by specifying - structure=Numeric String. - To match all those records with west-bounding-coordinate greater - than -114 we use the following query: - - @attr 4=109 @attr 2=5 @attr gils 1=2038 -114 - - - - - - - Present - - 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. - - - - Scan - - 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. - - - - Sort - - - 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. - - - - Close - - 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. - - - - - - - The Record Model - - - 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 record schema 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. - - - - The record model described in this chapter applies to the fundamental, - structured - record type grs as introduced in - section . - - - - Records pass through three different states during processing in the - system. - - - - - - - - - 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: - - - - - - - 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.), - - - - - - - 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. - - - - - - - - - Local Representation - - - 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. - - - - The RecordType parameter in the zebra.cfg file, or - the -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 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 - "grs" keyboard, separated by "." characters. - - - - Three basic subtypes to the grs type are - currently available: - - - - - - grs.sgml - - - This is the canonical input format — - described below. It is a simple SGML-like syntax. - - - - - grs.regx.filter - - - This enables a user-supplied input - filter. The mechanisms of these filters are described below. - - - - - grs.marc.abstract syntax - - - This allows Zebra to read - records in the ISO2709 (MARC) encoding standard. In this case, the - last paramemeter abstract syntax names the - .abs file (see below) - which describes the specific MARC structure of the input record as - well as the indexing rules. - - - - - - - - Canonical Input Format - - - 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. - - - - To use the canonical format specify grs.sgml as - the record type. - - - - Consider a record describing an information resource (such a record is - sometimes known as a locator record). - 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: - - - - - - <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> - - - - - - - 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. - - - - The keywords surrounded by <...> are - tags, while the sections of text - in between are the 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 </, and containing the same symbolic - tag-name as the corresponding opening tag. - The general closing tag - <>/ - - terminates the element started by the last opening tag. The - structuring of elements is significant. - The element Telephone, - for instance, may be indexed and presented to the client differently, - depending on whether it appears inside the - Distributor element, or some other, - structured data element such a Supplier element. - - - - Record Root - - - 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 - ). - 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): - - - - - - <gils> - <title>Zen and the Art of Motorcycle Maintenance</title> - </gils> - - - - - - - - Variants - - - Zebra allows you to provide individual data elements in a number of - 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 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 - different languages. - - - - - - <title> - <var lang lang "eng"> - Zen and the Art of Motorcycle Maintenance</> - <var lang lang "dan"> - Zen og Kunsten at Vedligeholde en Motorcykel</> - </title> - - - - - - The syntax of the variant element is - <var class type value>. - The available values for the class and - type fields are given by the variant set - that is associated with the current schema - (see section ). - - - - 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 class and - value 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. - - - - Variant elements can be nested. The element - - - - - - <title> - <var lang lang "eng"><var body iana "text/plain"> - Zen and the Art of Motorcycle Maintenance - </title> - - - - - - Associates two variant components to the variant list for the title - element. - - - - Given the nesting rules described above, we could write - - - - - - <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> - - - - - - 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. - - - - - - - - Input Filters - - - 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 - .flt. - The system looks for the files in the directories given in the - profilePath setting in the - zebra.cfg files. - The record type for the filter is - grs.regx.filter-filename - (fundamental type grs, file read - type regx, argument - filter-filename). - - - - 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. - - - - An expression can be either of the following: - - - - - - - INIT - - - 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. - - - - - BEGIN - - - Matches the beginning of the record. It can be used to - initialize variables, etc. Typically, the - BEGIN rule is also used - to establish the root node of the record. - - - - - END - - - Matches the end of the record - when all of the contents - of the record has been processed. - - - - - /pattern/ - - - Matches a string of characters from the input record. - - - - - BODY - - - This keyword may only be used between two patterns. - It matches everything between (not including) those patterns. - - - - - FINISH - - - 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 - INIT step. - - - - - - - - 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, $2, etc. - - - - The available statements are: - - - - - - - begin type [parameter ... ] - - - Begin a new - data element. The type is one of the following: - - - - record - - - Begin a new record. The followingparameter should be the - name of the schema that describes the structure of the record, eg. - gils or wais (see below). - The begin record call should precede - any other use of the begin statement. - - - - - element - - - Begin a new tagged element. The parameter is the - name of the tag. If the tag is not matched anywhere in the tagsets - referenced by the current schema, it is treated as a local string - tag. - - - - - variant - - - Begin a new node in a variant tree. The parameters are - class type value. - - - - - - - - - data - - - Create a data element. The concatenated arguments make - up the value of the data element. - The option -text signals that - the layout (whitespace) of the data should be retained for - transmission. - The option -element - tag wraps the data up in - the tag. - The use of the -element option is equivalent to - preceding the command with a begin - element command, and following - it with the end command. - - - - - end [type] - - - Close a tagged element. If no parameter is given, - the last element on the stack is terminated. - The first parameter, if any, is a type name, similar - to the begin statement. - For the element type, a tag - name can be provided to terminate a specific tag. - - - - - - - - The following input filter reads a Usenet news file, producing a - record in the WAIS schema. Note that the body of a news posting is - separated from the list of headers by a blank line (or rather a - sequence of two newline characters. - - - - - - BEGIN { begin record wais } - - /^From:/ BODY /$/ { 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 - } - - - - - - 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. - - - - NOTE: Tcl support is not currently available, but will be - included with one of the next alpha or beta releases. - - - - NOTE: Variant support is not currently available in the input - filter, but will be included with one of the next alpha or beta - releases. - - - - - - - - Internal Representation - - - 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: - - - - - - TITLE "Zen and the Art of Motorcycle Maintenance" - ROOT - AUTHOR "Robert Pirsig" - - - - - - A slightly more complex record would have the author element consist - of two elements, a surname and a first name: - - - - - - TITLE "Zen and the Art of Motorcycle Maintenance" - ROOT - FIRST-NAME "Robert" - AUTHOR - SURNAME "Pirsig" - - - - - - 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. - - - - Tagged Elements - - - 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). - - - - - - Variants - - - 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 variant form of the - tagged element identified by the tag which parents the variant tree. - The following title element occurs in two different languages: - - - - - - VARIANT LANG=ENG "War and Peace" - TITLE - VARIANT LANG=DAN "Krig og Fred" - - - - - - 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. - - - - - - Data Elements - - - Data nodes have no children (they are always leaf nodes in the record - tree). - - - - - Documentation needs extension here about types of nodes - numerical, - textual, etc., plus the various types of inclusion notes. - - - - - - - - - Configuring Your Data Model - - - 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 profilePath - setting in the zebra.cfg file. - - - - The Abstract Syntax - - - 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: - - - - - - - - - The object identifier of the Z39.50 schema associated - with the ARS, so that it can be referred to by the client. - - - - - - 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. - - - - - - 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. - - - - - - The variant set which is used in the profile. This provides a - vocabulary for specifying the forms of data that appear inside - the records. - - - - - - 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 element - specifications, which contain information equivalent to the - Espec-1 syntax of Z39.50. - - - - - - Map tables, which may specify mappings to - other database profiles, if desired. - - - - - - Possibly, a set of rules describing the mapping of elements to a - MARC representation. - - - - - - - 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. - - - - - - - - - Several of the entries above simply refer to other files, which - describe the given objects. - - - - - - The Configuration Files - - - This section describes the syntax and use of the various tables which - are used by the retrieval module. - - - - 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. - - - - 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 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 - file. Some settings are optional (o), whicle others again are - mandatory (m). - - - - - - The Abstract Syntax (.abs) Files - - - 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. - - - - 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, <gils>, the system will look - for the profile definition in the file gils.abs. - Profile definitions are cached, so they only have to be read once - during the lifespan of the current process. - - - - When writing your own input filters, the - record-begin command - introduces the profile, and should always be called first thing when - introducing a new record. - - - - The file may contain the following directives: - - - - - - - name symbolic-name - - - (m) This provides a shorthand name or - description for the profile. Mostly useful for diagnostic purposes. - - - - - reference OID-name - - - (m) The reference name of the OID for the profile. - The reference names can be found in the util - module of YAZ. - - - - - attset filename - - - (m) The attribute set that is used for - indexing and searching records belonging to this profile. - - - - - tagset filename - - - (o) The tag set (if any) that describe - that fields of the records. - - - - - varset filename - - - (o) The variant set used in the profile. - - - - - maptab filename - - - (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. - - - - marc filename - - - (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. - - - - esetname name filename - - - (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. - - - - any tags - - - (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 elm directive below. - - - - elm path name attributes - - - (o,r) Adds an element to the abstract record syntax of the schema. - The 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 name is the name of the element, and - the 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. - The attributes can be qualified with 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 . - The default field type is "w" for word. - - - - - - - - The mechanism for controlling indexing is not adequate for - complex databases, and will probably be moved into a separate - configuration table eventually. - - - - - The following is an excerpt from the abstract syntax file for the GILS - profile. - - - - - - 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 ! - - - - - - - - The Attribute Set (.att) Files - - - This file type describes the Use elements of - an attribute set. - It contains the following directives. - - - - - - name symbolic-name - - - (m) This provides a shorthand name or - description for the attribute set. - Mostly useful for diagnostic purposes. - - - - reference OID-name - - - (m) The reference name of the OID for - the attribute set. - The reference names can be found in the util - module of YAZ. - - - - include filename - - - (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 bib-1 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. - - - - att - att-value att-name [local-value] - - - (o,r) This - repeatable directive introduces a new attribute to the set. The - attribute value is stored in the index (unless a - local-value is - given, in which case this is stored). The name is used to refer to the - attribute from the abstract syntax. - - - - - - - This is an excerpt from the GILS attribute set definition. - Notice how the file describing the bib-1 - attribute set is referenced. - - - - - - name gils - reference GILS-attset - include bib1.att - - att 2001 distributorName - att 2002 indextermsControlled - att 2003 purpose - att 2004 accessConstraints - att 2005 useConstraints - - - - - - - - The Tag Set (.tag) Files - - - 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. - - - - - - - name symbolic-name - - - (m) This provides a shorthand name or - description for the tag set. Mostly useful for diagnostic purposes. - - - - reference OID-name - - - (o) The reference name of the OID for the tag set. - The reference names can be found in the util - module of YAZ. - The directive is optional, since not all tag sets - are registered outside of their schema. - - - - type integer - - - (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). - - - - include filename - - - (o,r) This directive is used - to include the definitions of other tag sets into the current one. - - - - tag number names type - - - (o,r) Introduces a new tag to the set. - The number 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 names 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 type is th recommended datatype of - the tag. - It should be one of the following: - - - - - structured - - - - - - string - - - - - - numeric - - - - - - bool - - - - - - oid - - - - - - generalizedtime - - - - - - intunit - - - - - - int - - - - - - octetstring - - - - - - null - - - - - - - - - - - - The following is an excerpt from the TagsetG definition file. - - - - - 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 - - - - - - - The Variant Set (.var) Files - - - The variant set file is a straightforward representation of the - variant set definitions associated with the protocol. At present, only - the Variant-1 set is known. - - - - These are the directives allowed in the file. - - - - - - - name symbolic-name - - - (m) This provides a shorthand name or - description for the variant set. Mostly useful for diagnostic purposes. - - - - reference OID-name - - - (o) The reference name of the OID for - the variant set, if one is required. The reference names can be found - in the util module of YAZ. - - - - class integer class-name - - - (m,r) Introduces a new - class to the variant set. - - - - type integer type-name datatype - - - (m,r) Addes a - new type to the current class (the one introduced by the most recent - class directive). - The type names belong to the same name space as the one used - in the tag set definition file. - - - - - - - The following is an excerpt from the file describing the variant set - Variant-1. - - - - - - 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 - - - - - - - - The Element Set (.est) Files - - - 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 Espec-1 - syntax of the Z39.50 specification. - In fact, the internal representation of an element set - specification is identical to the Espec-1 structure, - and we'll refer you to the description of that structure for most of - the detailed semantics of the directives below. - - - - - 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. - - - - - The directives available in the element set file are as follows: - - - - - - defaultVariantSetId OID-name - - - (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 - Variant-1 should be given here. - - - - defaultVariantRequest variant-request - - - (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. - - - - simpleElement - path ['variant' variant-request] - - - (o,r) This corresponds to a simple element request - in Espec-1. - The path consists of a sequence of tag-selectors, where each of - these can consist of either: - - - - - - - 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. - - - - - - A WildThing, represented as a question mark (?), possibly - followed by a colon (:) followed by an occurrences - specification (see below). - - - - - - 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). - - - - - - - - - The occurrences-specification can be either the string - all, the string last, 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). - - - - 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 Espec-1, - but it works in this implementation). - - - - - - - The following is an example of an element specification belonging to - the GILS profile. - - - - - - simpleelement (1,10) - simpleelement (1,12) - simpleelement (2,1) - simpleelement (1,14) - simpleelement (4,1) - simpleelement (4,52) - - - - - - - - The Schema Mapping (.map) Files - - - 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. - - - - 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. - - - - These are the directives of the schema mapping file format: - - - - - - - targetName name - - - (m) A symbolic name for the target schema - of the table. Useful mostly for diagnostic purposes. - - - - targetRef OID-name - - - (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 oid - module of YAZ. - - - - map element-name target-path - - - (o,r) Adds - an element mapping rule to the table. - - - - - - - - - The MARC (ISO2709) Representation (.mar) Files - - - 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. - - - - 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. - - - - - - Field Structure and Character Sets - - - - 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 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 - - - - - - - index field type code - - - 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 . - - - - sort field code type - - - 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. - - - - completeness boolean - - - This directive enables or disables complete field indexing. - The value of the 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 " " 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. - - - - charmap filename - - - This is the filename of the character - map to be used for this index for field type. - - - - - - - The contents of the character map files are structured as follows: - - - - - - - lowercase value-set - - - 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: - - - - - - - - Backslashes may be used to introduce three-digit octal, or - two-digit hex representations of single characters - (preceded by 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. - - - - - - 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. - - - - - - 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. - - - - - - - - - uppercase value-set - - - 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 - lowercase directive. - - - - space value-set - - - 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 - uppercase and lowercase - directives. - - - - map value-set - target - - - 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 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. - - - - - - - - - - - Exchange Formats - - - Converting records from the internal structure to en exchange format - is largely an automatic process. Currently, the following exchange - formats are supported: - - - - - - - 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. - - - - - - 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. - - - - - - 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 ), 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. - - - - - - Explain. This representation is only available for records - belonging to the Explain schema. - - - - - - 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). - - - - - - 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. - - - - - - - - - -