-<chapter id="quick-start">
- <title>Quick Start </title>
-
- <para>
- In this section, we will test the system by indexing a small set of sample
- GILS records that are included with the software distribution. Go to the
- <literal>test/gils</literal> subdirectory of the distribution archive.
- There you will find a configuration
- file named <literal>zebra.cfg</literal> with the following contents:
-
- <screen>
- # Where are the YAZ tables located.
- profilePath: ../../../yaz/tab ../../tab
-
- # Files that describe the attribute sets supported.
- attset: bib1.att
- attset: gils.att
- </screen>
- </para>
-
- <para>
- Now, edit the file and set <literal>profilePath</literal> to the path of the
- YAZ profile tables (sub directory <literal>tab</literal> of the YAZ
- distribution archive).
- </para>
-
- <para>
- The 48 test records are located in the sub directory
- <literal>records</literal>. To index these, type:
-
- <screen>
- $ ../../index/zebraidx -t grs.sgml update records
- </screen>
- </para>
-
- <para>
- In the command above the option <literal>-t</literal> specified the record
- type — in this case <literal>grs.sgml</literal>.
- The word <literal>update</literal> followed
- by a directory root updates all files below that directory node.
- </para>
-
- <para>
- If your indexing command was successful, you are now ready to
- fire up a server. To start a server on port 2100, type:
-
- <screen>
- $ ../../index/zebrasrv tcp:@:2100
- </screen>
-
- </para>
-
- <para>
- The Zebra index that you have just created has a single database
- named <literal>Default</literal>.
- The database contains records structured according to
- the GILS profile, and the server will
- return records in either either USMARC, GRS-1, or SUTRS depending
- on what your client asks for.
- </para>
-
- <para>
- To test the server, you can use any Z39.50 client (1992 or later).
- For instance, you can use the demo client that comes with YAZ: Just
- cd to the <literal>client</literal> subdirectory of the YAZ distribution
- and type:
- </para>
- <para>
- <screen>
- $ ./yaz-client tcp:localhost:2100
- </screen>
- </para>
-
- <para>
- When the client has connected, you can type:
- </para>
-
-<para>
-
- <screen>
- Z> find surficial
- Z> show 1
- </screen>
- </para>
-
- <para>
- The default retrieval syntax for the client is USMARC. To try other
- formats for the same record, try:
- </para>
- <para>
- <screen>
- Z>format sutrs
- Z>show 1
- Z>format grs-1
- Z>show 1
- Z>elements B
- Z>show 1
- </screen>
- </para>
-
- <note>
- <para>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.
- </para>
- </note>
- <para>
- If you've made it this far, there's a good chance that
- you've got through the compilation OK.
- </para>
-
-</chapter>
-
<chapter id="administration">
+ <!-- $Id: administration.xml,v 1.39 2006-06-13 13:45:08 marc Exp $ -->
<title>Administrating Zebra</title>
-
+ <!-- ### It's a bit daft that this chapter (which describes half of
+ the configuration-file formats) is separated from
+ "recordmodel-grs.xml" (which describes the other half) by the
+ instructions on running zebraidx and zebrasrv. Some careful
+ re-ordering is required here.
+ -->
+
<para>
Unlike many simpler retrieval systems, Zebra supports safe, incremental
updates to an existing index.
<term>Modify</term>
<listitem>
<para>
- The record has already been indexed. In this case
- either the contents of the record or the location (file) of the record
- indicates that it has been indexed before.
+ The record has already been indexed.
+ In this case either the contents of the record or the location
+ (file) of the record indicates that it has been indexed before.
</para>
</listitem>
</varlistentry>
<para>
Please note that in both the modify- and delete- case the Zebra
- indexer must be able to generate a unique key that identifies the record in
- question (more on this below).
+ indexer must be able to generate a unique key that identifies the record
+ in question (more on this below).
</para>
<para>
<para>
Both the Zebra administrative tool and the Z39.50 server share a
- set of index files and a global configuration file. The
- name of the configuration file defaults to <literal>zebra.cfg</literal>.
+ set of index files and a global configuration file.
+ The name of the configuration file defaults to
+ <literal>zebra.cfg</literal>.
The configuration file includes specifications on how to index
various kinds of records and where the other configuration files
are located. <literal>zebrasrv</literal> and <literal>zebraidx</literal>
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 <literal>-t</literal> or specify a
<para>
You can edit the configuration file with a normal text editor.
- parameter names and values are seperated by colons in the file. Lines
- starting with a hash sign (<literal>#</literal>) are
+ parameter names and values are separated by colons in the file. Lines
+ starting with a hash sign (<literal>#</literal>) are
treated as comments.
</para>
explained further in the following sections.
</para>
+ <!--
+ FIXME - Didn't Adam make something to have multiple databases in multiple dirs...
+ -->
+
<para>
<variablelist>
<varlistentry>
<term>
<emphasis>group</emphasis>
- .recordType[<emphasis>.name</emphasis>]
+ .recordType[<emphasis>.name</emphasis>]:
+ <replaceable>type</replaceable>
</term>
<listitem>
<para>
</listitem>
</varlistentry>
<varlistentry>
- <term><emphasis>group</emphasis>.recordId</term>
+ <term><emphasis>group</emphasis>.recordId:
+ <replaceable>record-id-spec</replaceable></term>
<listitem>
<para>
Specifies how the records are to be identified when updated. See
- section <xref linkend="locating-records"/>.
+ <xref linkend="locating-records"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><emphasis>group</emphasis>.database</term>
+ <term><emphasis>group</emphasis>.database:
+ <replaceable>database</replaceable></term>
<listitem>
<para>
Specifies the Z39.50 database name.
+ <!-- FIXME - now we can have multiple databases in one server. -H -->
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><emphasis>group</emphasis>.storeKeys</term>
+ <term><emphasis>group</emphasis>.storeKeys:
+ <replaceable>boolean</replaceable></term>
<listitem>
<para>
Specifies whether key information should be saved for a given
group of records. If you plan to update/delete this type of
records later this should be specified as 1; otherwise it
- should be 0 (default), to save register space. See section
- <xref linkend="file-ids"/>.
+ should be 0 (default), to save register space.
+ <!-- ### this is the first mention of "register" -->
+ See <xref linkend="file-ids"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><emphasis>group</emphasis>.storeData</term>
+ <term><emphasis>group</emphasis>.storeData:
+ <replaceable>boolean</replaceable></term>
<listitem>
<para>
Specifies whether the records should be stored internally
</listitem>
</varlistentry>
<varlistentry>
- <term>register</term>
+ <!-- ### probably a better place to define "register" -->
+ <term>register: <replaceable>register-location</replaceable></term>
<listitem>
<para>
Specifies the location of the various register files that Zebra uses
- to represent your databases. See section
- <xref linkend="register-location"/>.
+ to represent your databases.
+ See <xref linkend="register-location"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>shadow</term>
+ <term>shadow: <replaceable>register-location</replaceable></term>
<listitem>
<para>
Enables the <emphasis>safe update</emphasis> facility of Zebra, and
tells the system where to place the required, temporary files.
- See section
- <xref linkend="shadow-registers"/>.
+ See <xref linkend="shadow-registers"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>lockDir</term>
+ <term>lockDir: <replaceable>directory</replaceable></term>
<listitem>
<para>
Directory in which various lock files are stored.
</listitem>
</varlistentry>
<varlistentry>
- <term>keyTmpDir</term>
+ <term>keyTmpDir: <replaceable>directory</replaceable></term>
<listitem>
<para>
- Directory in which temporary files used during zebraidx' update
+ Directory in which temporary files used during zebraidx's update
phase are stored.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>setTmpDir</term>
+ <term>setTmpDir: <replaceable>directory</replaceable></term>
<listitem>
<para>
Specifies the directory that the server uses for temporary result sets.
</listitem>
</varlistentry>
<varlistentry>
- <term>profilePath</term>
+ <term>profilePath: <replaceable>path</replaceable></term>
<listitem>
<para>
- 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.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>attset</term>
+ <term>attset: <replaceable>filename</replaceable></term>
<listitem>
<para>
Specifies the filename(s) of attribute set files for use in
(<literal>bib1.att</literal>).
The <literal>profilePath</literal> setting is used to look for
the specified files.
- See section <xref linkend="attset-files"/>
+ See <xref linkend="attset-files"/>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>memMax: <replaceable>size</replaceable></term>
+ <listitem>
+ <para>
+ Specifies <replaceable>size</replaceable> of internal memory
+ to use for the zebraidx program.
+ The amount is given in megabytes - default is 4 (4 MB).
+ The more memory, the faster large updates happen, up to about
+ half the free memory available on the computer.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>tempfiles: <replaceable>Yes/Auto/No</replaceable></term>
+ <listitem>
+ <para>
+ Tells zebra if it should use temporary files when indexing. The
+ default is Auto, in which case zebra uses temporary files only
+ if it would need more that <replaceable>memMax</replaceable>
+ megabytes of memory. This should be good for most uses.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>root: <replaceable>dir</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a directory base for Zebra. All relative paths
+ given (in profilePath, register, shadow) are based on this
+ directory. This setting is useful if your Zebra server
+ is running in a different directory from where
+ <literal>zebra.cfg</literal> is located.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>passwd: <replaceable>file</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a file with description of user accounts for Zebra.
+ The format is similar to that known to Apache's htpasswd files
+ and UNIX' passwd files. Non-empty lines not beginning with
+ # are considered account lines. There is one account per-line.
+ A line consists of fields separate by a single colon character.
+ First field is username, second is password.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>passwd.c: <replaceable>file</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a file with description of user accounts for Zebra.
+ File format is similar to that used by the passwd directive except
+ that the password are encrypted. Use Apache's htpasswd or similar
+ for maintenanace.
</para>
</listitem>
</varlistentry>
+
<varlistentry>
- <term>memMax</term>
+ <term>perm.<replaceable>user</replaceable>:
+ <replaceable>permstring</replaceable></term>
<listitem>
<para>
- Specifies size of internal memory to use for the zebraidx program. The
- amount is given in megabytes - default is 4 (4 MB).
+ Specifies permissions (priviledge) for a user that are allowed
+ to access Zebra via the passwd system. There are two kinds
+ of permissions currently: read (r) and write(w). By default
+ users not listed in a permission directive are given the read
+ priviledge. To specify permissions for a user with no
+ username, or Z39.50 anonymous style use
+ <literal>anonymous</literal>. The permstring consists of
+ a sequence of characters. Include character <literal>w</literal>
+ for write/update access, <literal>r</literal> for read access.
</para>
</listitem>
</varlistentry>
+
+ <varlistentry>
+ <term>dbaccess <replaceable>accessfile</replaceable></term>
+ <listitem>
+ <para>
+ Names a file which lists database subscriptions for individual users.
+ The access file should consists of lines of the form <literal>username:
+ dbnames</literal>, where dbnames is a list of database names, seprated by
+ '+'. No whitespace is allowed in the database list.
+ </para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
</para>
<title>Locating Records</title>
<para>
- 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 <literal>zebraidx</literal>.
+ run <literal>zebraidx</literal>.
That is, when a client wishes to retrieve a record
following a search operation, the files are accessed from the place
where you originally put them - if you remove the files (without
- running <literal>zebraidx</literal> again, the client
- will receive a diagnostic message.
+ running <literal>zebraidx</literal> again, the server will return
+ diagnostic number 14 (``System error in presenting records'') to
+ the client.
</para>
<para>
<para>
<screen>
- profilePath: /usr/local/yaz
+ profilePath: /usr/local/idzebra/tab
attset: bib1.att
simple.recordType: text
simple.database: textbase
disk space than simpler indexing methods, but it makes it easier for
you to keep the index in sync with a frequently changing set of data.
If you combine this system with the <emphasis>safe update</emphasis>
- facility (see below), you never have to take your server offline for
+ facility (see below), you never have to take your server off-line for
maintenance or register updating purposes.
</para>
in the configuration file. In addition, you should set
<literal>storeKeys</literal> to <literal>1</literal>, since the Zebra
indexer must save additional information about the contents of each record
- in order to modify the indices correctly at a later time.
+ in order to modify the indexes correctly at a later time.
</para>
+ <!--
+ FIXME - There must be a simpler way to do this with Adams string tags -H
+ -->
+
<para>
For example, to update records of group <literal>esdd</literal>
located below
and then run <literal>zebraidx</literal> with the
<literal>update</literal> command.
</para>
+ <!-- ### what happens if a file contains multiple records? -->
</sect1>
<sect1 id="generic-ids">
<title>Indexing with General Record IDs</title>
<para>
- When using this method you construct an (almost) 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
</para>
<para>
- (see section <xref linkend="data-model"/>
+ (see <xref linkend="record-model-grs"/>
for details of how the mapping between elements of your records and
searchable attributes is established).
</para>
each directory in the order specified and use the next specified
directories as needed.
The <emphasis>size</emphasis> is an integer followed by a qualifier
- code, <literal>M</literal> for megabytes,
+ code,
+ <literal>b</literal> for bytes,
<literal>k</literal> for kilobytes.
+ <literal>M</literal> for megabytes,
+ <literal>G</literal> for gigabytes.
</para>
<para>
For instance, if you have allocated two disks for your register, and
the first disk is mounted
- on <literal>/d1</literal> and has 200 Mb of free space and the
- second, mounted on <literal>/d2</literal> has 300 Mb, you could
+ on <literal>/d1</literal> and has 2GB of free space and the
+ second, mounted on <literal>/d2</literal> has 3.6 GB, you could
put this entry in your configuration file:
<screen>
- register: /d1:200M /d2:300M
+ register: /d1:2G /d2:3600M
</screen>
</para>
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.
</para>
</sect1>
<literal>zebra.cfg</literal> file.
The syntax of the <literal>shadow</literal> entry is exactly the
same as for the <literal>register</literal> entry
- (see section <xref linkend="register-location"/>).
+ (see <xref linkend="register-location"/>).
The location of the shadow area should be
<emphasis>different</emphasis> from the location of the main register
area (if you have specified one - remember that if you provide no
<screen>
register: /d1:500M
-
shadow: /scratch1:100M /scratch2:200M
</screen>
In order to make changes to the system take effect for the
users, you'll have to submit a "commit" command after a
(sequence of) update operation(s).
- You can ask the indexer to commit the changes immediately
- after the update operation:
</para>
<para>
<screen>
- $ zebraidx update /d1/records update /d2/more-records commit
+ $ zebraidx update /d1/records
+ $ zebraidx commit
</screen>
</para>
<para>
<screen>
- $ 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
</screen>
</sect2>
</sect1>
+
+
+ <sect1 id="administration-ranking">
+ <title>Relevance Ranking and Sorting of Result Sets</title>
+
+ <sect2>
+ <title>Overview</title>
+ <para>
+ The default ordering of a result set is left up to the server,
+ which inside Zebra means sorting in ascending document ID order.
+ This is not always the order humans want to browse the sometimes
+ quite large hit sets. Ranking and sorting comes to the rescue.
+ </para>
+
+ <para>
+ In cases where a good presentation ordering can be computed at
+ indexing time, we can use a fixed <literal>static ranking</literal>
+ scheme, which is provided for the <literal>alvis</literal>
+ indexing filter. This defines a fixed ordering of hit lists,
+ independently of the query issued.
+ </para>
+
+ <para>
+ There are cases, however, where relevance of hit set documents is
+ highly dependent on the query processed.
+ Simply put, <literal>dynamic relevance ranking</literal>
+ sorts a set of retrieved records such that those most likely to be
+ relevant to your request are retrieved first.
+ Internally, Zebra retrieves all documents that satisfy your
+ query, and re-orders the hit list to arrange them based on
+ a measurement of similarity between your query and the content of
+ each record.
+ </para>
+
+ <para>
+ Finally, there are situations where hit sets of documents should be
+ <literal>sorted</literal> during query time according to the
+ lexicographical ordering of certain sort indexes created at
+ indexing time.
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-ranking-static">
+ <title>Static Ranking</title>
+
+ <para>
+ Zebra uses internally inverted indexes to look up term occurencies
+ in documents. Multiple queries from different indexes can be
+ combined by the binary boolean operations <literal>AND</literal>,
+ <literal>OR</literal> and/or <literal>NOT</literal> (which
+ is in fact a binary <literal>AND NOT</literal> operation).
+ To ensure fast query execution
+ speed, all indexes have to be sorted in the same order.
+ </para>
+ <para>
+ The indexes are normally sorted according to document
+ <literal>ID</literal> in
+ ascending order, and any query which does not invoke a special
+ re-ranking function will therefore retrieve the result set in
+ document
+ <literal>ID</literal>
+ order.
+ </para>
+ <para>
+ If one defines the
+ <screen>
+ staticrank: 1
+ </screen>
+ directive in the main core Zebra configuration file, the internal document
+ keys used for ordering are augmented by a preceding integer, which
+ contains the static rank of a given document, and the index lists
+ are ordered
+ first by ascending static rank,
+ then by ascending document <literal>ID</literal>.
+ Zero
+ is the ``best'' rank, as it occurs at the
+ beginning of the list; higher numbers represent worse scores.
+ </para>
+ <para>
+ The experimental <literal>alvis</literal> filter provides a
+ directive to fetch static rank information out of the indexed XML
+ records, thus making <emphasis>all</emphasis> hit sets ordered
+ after <emphasis>ascending</emphasis> static
+ rank, and for those doc's which have the same static rank, ordered
+ after <emphasis>ascending</emphasis> doc <literal>ID</literal>.
+ See <xref linkend="record-model-alvisxslt"/> for the gory details.
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-ranking-dynamic">
+ <title>Dynamic Ranking</title>
+ <para>
+ In order to fiddle with the static rank order, it is necessary to
+ invoke additional re-ranking/re-ordering using dynamic
+ ranking or score functions. These functions return positive
+ integer scores, where <emphasis>highest</emphasis> score is
+ ``best'';
+ hit sets are sorted according to <emphasis>descending</emphasis>
+ scores (in contrary
+ to the index lists which are sorted according to
+ ascending rank number and document ID).
+ </para>
+ <para>
+ Dynamic ranking is enabled by a directive like one of the
+ following in the zebra configuration file (use only one of these a time!):
+ <screen>
+ rank: rank-1 # default TDF-IDF like
+ rank: rank-static # dummy do-nothing
+ </screen>
+ </para>
-</chapter>
+ <para>
+ Dynamic ranking is done at query time rather than
+ indexing time (this is why we
+ call it ``dynamic ranking'' in the first place ...)
+ It is invoked by adding
+ the Bib-1 relation attribute with
+ value ``relevance'' to the PQF query (that is,
+ <literal>@attr 2=102</literal>, see also
+ <ulink url="&url.z39.50;bib1.html">
+ The BIB-1 Attribute Set Semantics</ulink>, also in
+ <ulink url="&url.z39.50.attset.bib1;">HTML</ulink>).
+ To find all articles with the word <literal>Eoraptor</literal> in
+ the title, and present them relevance ranked, issue the PQF query:
+ <screen>
+ @attr 2=102 @attr 1=4 Eoraptor
+ </screen>
+ </para>
+
+ <sect3 id="administration-ranking-dynamic-rank1">
+ <title>Dynamically ranking using PQF queries with the 'rank-1'
+ algorithm</title>
+
+ <para>
+ The default <literal>rank-1</literal> ranking module implements a
+ TF/IDF (Term Frequecy over Inverse Document Frequency) like
+ algorithm. In contrast to the usual defintion of TF/IDF
+ algorithms, which only considers searching in one full-text
+ index, this one works on multiple indexes at the same time.
+ More precisely,
+ Zebra does boolean queries and searches in specific addressed
+ indexes (there are inverted indexes pointing from terms in the
+ dictionary to documents and term positions inside documents).
+ It works like this:
+ <variablelist>
+ <varlistentry>
+ <term>Query Components</term>
+ <listitem>
+ <para>
+ First, the boolean query is dismantled into it's principal components,
+ i.e. atomic queries where one term is looked up in one index.
+ For example, the query
+ <screen>
+ @attr 2=102 @and @attr 1=1010 Utah @attr 1=1018 Springer
+ </screen>
+ is a boolean AND between the atomic parts
+ <screen>
+ @attr 2=102 @attr 1=1010 Utah
+ </screen>
+ and
+ <screen>
+ @attr 2=102 @attr 1=1018 Springer
+ </screen>
+ which gets processed each for itself.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Atomic hit lists</term>
+ <listitem>
+ <para>
+ Second, for each atomic query, the hit list of documents is
+ computed.
+ </para>
+ <para>
+ In this example, two hit lists for each index
+ <literal>@attr 1=1010</literal> and
+ <literal>@attr 1=1018</literal> are computed.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Atomic scores</term>
+ <listitem>
+ <para>
+ Third, each document in the hit list is assigned a score (_if_ ranking
+ is enabled and requested in the query) using a TF/IDF scheme.
+ </para>
+ <para>
+ In this example, both atomic parts of the query assign the magic
+ <literal>@attr 2=102</literal> relevance attribute, and are
+ to be used in the relevance ranking functions.
+ </para>
+ <para>
+ It is possible to apply dynamic ranking on only parts of the
+ PQF query:
+ <screen>
+ @and @attr 2=102 @attr 1=1010 Utah @attr 1=1018 Springer
+ </screen>
+ searches for all documents which have the term 'Utah' on the
+ body of text, and which have the term 'Springer' in the publisher
+ field, and sort them in the order of the relevance ranking made on
+ the body-of-text index only.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Hit list merging</term>
+ <listitem>
+ <para>
+ Fourth, the atomic hit lists are merged according to the boolean
+ conditions to a final hit list of documents to be returned.
+ </para>
+ <para>
+ This step is always performed, independently of the fact that
+ dynamic ranking is enabled or not.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Document score computation</term>
+ <listitem>
+ <para>
+ Fifth, the total score of a document is computed as a linear
+ combination of the atomic scores of the atomic hit lists
+ </para>
+ <para>
+ Ranking weights may be used to pass a value to a ranking
+ algorithm, using the non-standard BIB-1 attribute type 9.
+ This allows one branch of a query to use one value while
+ another branch uses a different one. For example, we can search
+ for <literal>utah</literal> in the
+ <literal>@attr 1=4</literal> index with weight 30, as
+ well as in the <literal>@attr 1=1010</literal> index with weight 20:
+ <screen>
+ @attr 2=102 @or @attr 9=30 @attr 1=4 utah @attr 9=20 @attr 1=1010 city
+ </screen>
+ </para>
+ <para>
+ The default weight is
+ sqrt(1000) ~ 34 , as the Z39.50 standard prescribes that the top score
+ is 1000 and the bottom score is 0, encoded in integers.
+ </para>
+ <warning>
+ <para>
+ The ranking-weight feature is experimental. It may change in future
+ releases of zebra.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
-<chapter id="zebraidx">
- <title>Running the Maintenance Interface (zebraidx)</title>
+ <varlistentry>
+ <term>Re-sorting of hit list</term>
+ <listitem>
+ <para>
+ Finally, the final hit list is re-ordered according to scores.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
- <para>
- The following is a complete reference to the command line interface to
- the <literal>zebraidx</literal> application.
- </para>
+
+<!--
+Still need to describe the exact TF/IDF formula. Here's the info, need -->
+<!--to extract it in human readable form .. MC
+
+static int calc (void *set_handle, zint sysno, zint staticrank,
+ int *stop_flag)
+{
+ int i, lo, divisor, score = 0;
+ struct rank_set_info *si = (struct rank_set_info *) set_handle;
+
+ if (!si->no_rank_entries)
+ return -1; /* ranking not enabled for any terms */
+
+ for (i = 0; i < si->no_entries; i++)
+ {
+ yaz_log(log_level, "calc: i=%d rank_flag=%d lo=%d",
+ i, si->entries[i].rank_flag, si->entries[i].local_occur);
+ if (si->entries[i].rank_flag && (lo = si->entries[i].local_occur))
+ score += (8+log2_int (lo)) * si->entries[i].global_inv *
+ si->entries[i].rank_weight;
+ }
+ divisor = si->no_rank_entries * (8+log2_int (si->last_pos/si->no_entries));
+ score = score / divisor;
+ yaz_log(log_level, "calc sysno=" ZINT_FORMAT " score=%d", sysno, score);
+ if (score > 1000)
+ score = 1000;
+ /* reset the counts for the next term */
+ for (i = 0; i < si->no_entries; i++)
+ si->entries[i].local_occur = 0;
+ return score;
+}
+
+
+where lo = si->entries[i].local_occur is the local documents term-within-index frequency, si->entries[i].global_inv represents the IDF part (computed in static void *begin()), and
+si->entries[i].rank_weight is the weight assigner per index (default 34, or set in the @attr 9=xyz magic)
+
+Finally, the IDF part is computed as:
+
+static void *begin (struct zebra_register *reg,
+ void *class_handle, RSET rset, NMEM nmem,
+ TERMID *terms, int numterms)
+{
+ struct rank_set_info *si =
+ (struct rank_set_info *) nmem_malloc (nmem,sizeof(*si));
+ int i;
+
+ yaz_log(log_level, "rank-1 begin");
+ si->no_entries = numterms;
+ si->no_rank_entries = 0;
+ si->nmem=nmem;
+ si->entries = (struct rank_term_info *)
+ nmem_malloc (si->nmem, sizeof(*si->entries)*numterms);
+ for (i = 0; i < numterms; i++)
+ {
+ zint g = rset_count(terms[i]->rset);
+ yaz_log(log_level, "i=%d flags=%s '%s'", i,
+ terms[i]->flags, terms[i]->name );
+ if (!strncmp (terms[i]->flags, "rank,", 5))
+ {
+ const char *cp = strstr(terms[i]->flags+4, ",w=");
+ si->entries[i].rank_flag = 1;
+ if (cp)
+ si->entries[i].rank_weight = atoi (cp+3);
+ else
+ si->entries[i].rank_weight = 34; /* sqrroot of 1000 */
+ yaz_log(log_level, " i=%d weight=%d g="ZINT_FORMAT, i,
+ si->entries[i].rank_weight, g);
+ (si->no_rank_entries)++;
+ }
+ else
+ si->entries[i].rank_flag = 0;
+ si->entries[i].local_occur = 0; /* FIXME */
+ si->entries[i].global_occur = g;
+ si->entries[i].global_inv = 32 - log2_int (g);
+ yaz_log(log_level, " global_inv = %d g = " ZINT_FORMAT,
+ (int) (32-log2_int (g)), g);
+ si->entries[i].term = terms[i];
+ si->entries[i].term_index=i;
+ terms[i]->rankpriv = &(si->entries[i]);
+ }
+ return si;
+}
+
+
+where g = rset_count(terms[i]->rset) is the count of all documents in this specific index hit list, and the IDF part then is
+
+ si->entries[i].global_inv = 32 - log2_int (g);
+ -->
+
+ </para>
+
+
+ <para>
+ The <literal>rank-1</literal> algorithm
+ does not use the static rank
+ information in the list keys, and will produce the same ordering
+ with or without static ranking enabled.
+ </para>
- <para>
- Syntax
-
- <screen>
- $ zebraidx [options] command [directory] ...
- </screen>
-
- Options:
- <variablelist>
-
- <varlistentry>
- <term>-t <replaceable>type</replaceable></term>
- <listitem>
- <para>
- Update all files as <replaceable>type</replaceable>. Currently, the
- types supported are <literal>text</literal> and
- <literal>grs</literal><replaceable>.subtype</replaceable>.
- If no <replaceable>subtype</replaceable> is provided for the GRS
- (General Record Structure) type, the canonical input format
- is assumed (see section <xref linkend="local-representation"/>).
- Generally, it is probably advisable to specify the record types
- in the <literal>zebra.cfg</literal> file (see section
- <xref linkend="record-types"/>), to avoid confusion at
- subsequent updates.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-c <replaceable>config-file</replaceable></term>
- <listitem>
- <para>
- Read the configuration file
- <replaceable>config-file</replaceable> instead of
- <literal>zebra.cfg</literal>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-g <replaceable>group</replaceable></term>
- <listitem>
- <para>
- Update the files according to the group
- settings for <replaceable>group</replaceable> (see section
- <xref linkend="configuration-file"/>).
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-d <replaceable>database</replaceable></term>
- <listitem>
+ </sect3>
+
+ <!--
+ <sect3 id="administration-ranking-dynamic-rank1">
+ <title>Dynamically ranking PQF queries with the 'rank-static'
+ algorithm</title>
+ <para>
+ The dummy <literal>rank-static</literal> reranking/scoring
+ function returns just
+ <literal>score = max int - staticrank</literal>
+ in order to preserve the static ordering of hit sets that would
+ have been produced had it not been invoked.
+ Obviously, to combine static and dynamic ranking usefully,
+ it is necessary
+ to make a new ranking
+ function; this is left
+ as an exercise for the reader.
+ </para>
+ </sect3>
+ -->
+
+
+ <warning>
<para>
- The records located should be associated with the database name
- <replaceable>database</replaceable> for access through the Z39.50 server.
+ <literal>Dynamic ranking</literal> is not compatible
+ with <literal>estimated hit sizes</literal>, as all documents in
+ a hit set must be accessed to compute the correct placing in a
+ ranking sorted list. Therefore the use attribute setting
+ <literal>@attr 2=102</literal> clashes with
+ <literal>@attr 9=integer</literal>.
</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-m <replaceable>mbytes</replaceable></term>
- <listitem>
+ </warning>
+
+ <!--
+ we might want to add ranking like this:
+ UNPUBLISHED:
+ Simple BM25 Extension to Multiple Weighted Fields
+ Stephen Robertson, Hugo Zaragoza and Michael Taylor
+ Microsoft Research
+ ser@microsoft.com
+ hugoz@microsoft.com
+ mitaylor2microsoft.com
+ -->
+
+
+ <sect3 id="administration-ranking-dynamic-cql">
+ <title>Dynamically ranking CQL queries</title>
<para>
- Use <replaceable>mbytes</replaceable> of megabytes before flushing
- keys to background storage. This setting affects performance when
- updating large databases.
+ Dynamic ranking can be enabled during sever side CQL
+ query expansion by adding <literal>@attr 2=102</literal>
+ chunks to the CQL config file. For example
+ <screen>
+ relationModifier.relevant = 2=102
+ </screen>
+ invokes dynamic ranking each time a CQL query of the form
+ <screen>
+ Z> querytype cql
+ Z> f alvis.text =/relevant house
+ </screen>
+ is issued. Dynamic ranking can also be automatically used on
+ specific CQL indexes by (for example) setting
+ <screen>
+ index.alvis.text = 1=text 2=102
+ </screen>
+ which then invokes dynamic ranking each time a CQL query of the form
+ <screen>
+ Z> querytype cql
+ Z> f alvis.text = house
+ </screen>
+ is issued.
</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-n</term>
- <listitem>
- <para>
- Disable the use of shadow registers for this operation
- (see section <xref linkend="shadow-registers"/>).
+
+ </sect3>
+
+ </sect2>
+
+
+ <sect2 id="administration-ranking-sorting">
+ <title>Sorting</title>
+ <para>
+ Zebra sorts efficiently using special sorting indexes
+ (type=<literal>s</literal>; so each sortable index must be known
+ at indexing time, specified in the configuration of record
+ indexing. For example, to enable sorting according to the BIB-1
+ <literal>Date/time-added-to-db</literal> field, one could add the line
+ <screen>
+ xelm /*/@created Date/time-added-to-db:s
+ </screen>
+ to any <literal>.abs</literal> record-indexing configuration file.
+ Similarly, one could add an indexing element of the form
+ <screen><![CDATA[
+ <z:index name="date-modified" type="s">
+ <xsl:value-of select="some/xpath"/>
+ </z:index>
+ ]]></screen>
+ to any <literal>alvis</literal>-filter indexing stylesheet.
</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-s</term>
- <listitem>
<para>
- Show analysis of the indexing process. The maintenance
- program works in a read-only mode and doesn't change the state
- of the index. This options is very useful when you wish to test a
- new profile.
+ Indexing can be specified at searching time using a query term
+ carrying the non-standard
+ BIB-1 attribute-type <literal>7</literal>. This removes the
+ need to send a Z39.50 <literal>Sort Request</literal>
+ separately, and can dramatically improve latency when the client
+ and server are on separate networks.
+ The sorting part of the query is separate from the rest of the
+ query - the actual search specification - and must be combined
+ with it using OR.
</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-V</term>
- <listitem>
<para>
- Show Zebra version.
+ A sorting subquery needs two attributes: an index (such as a
+ BIB-1 type-1 attribute) specifying which index to sort on, and a
+ type-7 attribute whose value is be <literal>1</literal> for
+ ascending sorting, or <literal>2</literal> for descending. The
+ term associated with the sorting attribute is the priority of
+ the sort key, where <literal>0</literal> specifies the primary
+ sort key, <literal>1</literal> the secondary sort key, and so
+ on.
</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-v <replaceable>level</replaceable></term>
- <listitem>
- <para>
- Set the log level to <replaceable>level</replaceable>.
- <replaceable>level</replaceable> should be one of
- <literal>none</literal>, <literal>debug</literal>, and
- <literal>all</literal>.
+ <para>For example, a search for water, sort by title (ascending),
+ is expressed by the PQF query
+ <screen>
+ @or @attr 1=1016 water @attr 7=1 @attr 1=4 0
+ </screen>
+ whereas a search for water, sort by title ascending,
+ then date descending would be
+ <screen>
+ @or @or @attr 1=1016 water @attr 7=1 @attr 1=4 0 @attr 7=2 @attr 1=30 1
+ </screen>
+ </para>
+ <para>
+ Notice the fundamental differences between <literal>dynamic
+ ranking</literal> and <literal>sorting</literal>: there can be
+ only one ranking function defined and configured; but multiple
+ sorting indexes can be specified dynamically at search
+ time. Ranking does not need to use specific indexes, so
+ dynamic ranking can be enabled and disabled without
+ re-indexing; whereas, sorting indexes need to be
+ defined before indexing.
</para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
-
- <para>
- Commands
- <variablelist>
-
- <varlistentry>
- <term>update <replaceable>directory</replaceable></term>
- <listitem>
- <para>
- Update the register with the files contained in
- <replaceable>directory</replaceable>.
- If no directory is provided, a list of files is read from
- <literal>stdin</literal>.
- See section <xref linkend="administration"/>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>delete <replaceable>directory</replaceable></term>
- <listitem>
- <para>
- Remove the records corresponding to the files found under
- <replaceable>directory</replaceable> from the register.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>commit</term>
- <listitem>
- <para>
- Write the changes resulting from the last <literal>update</literal>
- commands to the register. This command is only available if the use of
- shadow register files is enabled (see section
- <xref linkend="shadow-registers"/>).
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
-
-</chapter>
-
-<chapter id="server">
- <title>The Z39.50 Server</title>
-
- <sect1 id="zebrasrv">
- <title>Running the Z39.50 Server (zebrasrv)</title>
-
- <para>
- <emphasis remap="bf">Syntax</emphasis>
-
- <screen>
- zebrasrv [options] [listener-address ...]
- </screen>
-
- </para>
-
- <para>
- <emphasis remap="bf">Options</emphasis>
- <variablelist>
-
- <varlistentry>
- <term>-a <replaceable>APDU file</replaceable></term>
- <listitem>
- <para>
- Specify a file for dumping PDUs (for diagnostic purposes).
- The special name "-" sends output to <literal>stderr</literal>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-c <replaceable>config-file</replaceable></term>
- <listitem>
- <para>
- Read configuration information from
- <replaceable>config-file</replaceable>.
- The default configuration is <literal>./zebra.cfg</literal>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-S</term>
- <listitem>
- <para>
- Don't fork on connection requests. This can be useful for
- symbolic-level debugging. The server can only accept a single
- connection in this mode.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-s</term>
- <listitem>
- <para>
- Use the SR protocol.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-z</term>
- <listitem>
- <para>
- Use the Z39.50 protocol (default). These two options complement
- eachother. You can use both multiple times on the same command
- line, between listener-specifications (see below). This way, you
- can set up the server to listen for connections in both protocols
- concurrently, on different local ports.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-l <replaceable>logfile</replaceable></term>
- <listitem>
- <para>
- Specify an output file for the diagnostic messages.
- The default is to write this information to <literal>stderr</literal>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-v <replaceable>log-level</replaceable></term>
- <listitem>
- <para>
- The log level. Use a comma-separated list of members of the set
- {fatal,debug,warn,log,all,none}.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-u <replaceable>username</replaceable></term>
- <listitem>
- <para>
- Set user ID. Sets the real UID of the server process to that of the
- given <replaceable>username</replaceable>.
- It's useful if you aren't comfortable with having the
- server run as root, but you need to start it as such to bind a
- privileged port.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-w <replaceable>working-directory</replaceable></term>
- <listitem>
- <para>
- Change working directory.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-i</term>
- <listitem>
- <para>
- Run under the Internet superserver, <literal>inetd</literal>.
- Make sure you use the logfile option <literal>-l</literal> in
- conjunction with this mode and specify the <literal>-l</literal>
- option before any other options.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-t <replaceable>timeout</replaceable></term>
- <listitem>
- <para>
- Set the idle session timeout (default 60 minutes).
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>-k <replaceable>kilobytes</replaceable></term>
- <listitem>
- <para>
- Set the (approximate) maximum size of
- present response messages. Default is 1024 Kb (1 Mb).
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
-
- <para>
- A <replaceable>listener-address</replaceable> consists of a transport
- mode followed by a colon (:) followed by a listener address.
- The transport mode is either <literal>ssl</literal> or
- <literal>tcp</literal>.
- </para>
-
- <para>
- For TCP, an address has the form
- </para>
-
- <para>
-
- <screen>
- hostname | IP-number [: portnumber]
- </screen>
-
- </para>
-
- <para>
- The port number defaults to 210 (standard Z39.50 port).
- </para>
-
- <para>
- Examples
- </para>
-
- <para>
-
- <screen>
- tcp:dranet.dra.com
-
- ssl:secure.lib.com:3000
- </screen>
-
- </para>
-
- <para>
- In both cases, the special hostname "@" is mapped to
- the address INADDR_ANY, which causes the server to listen on any local
- interface. To start the server listening on the registered port for
- Z39.50, and to drop root privileges once the ports are bound, execute
- the server like this (from a root shell):
- </para>
-
- <para>
-
- <screen>
- zebrasrv -u daemon tcp:@
- </screen>
-
- </para>
-
- <para>
- You can replace <literal>daemon</literal> with another user, eg.
- your own account, or a dedicated IR server account.
- </para>
-
- <para>
- The default behavior for <literal>zebrasrv</literal> is to establish
- a single TCP/IP listener, for the Z39.50 protocol, on port 9999.
- </para>
-
- </sect1>
-
- <sect1 id="protocol-support">
- <title>Z39.50 Protocol Support and Behavior</title>
-
- <sect2>
- <title>Initialization</title>
-
- <para>
- During initialization, the server will negotiate to version 3 of the
- Z39.50 protocol, and the option bits for Search, Present, Scan,
- NamedResultSets, and concurrentOperations will be set, if requested by
- the client. The maximum PDU size is negotiated down to a maximum of
- 1Mb by default.
- </para>
-
- </sect2>
-
- <sect2 id="search">
- <title>Search</title>
-
- <para>
- The supported query type are 1 and 101. All operators are currently
- supported with the restriction that only proximity units of type "word"
- are supported for the proximity operator.
- Queries can be arbitrarily complex.
- Named result sets are supported, and result sets can be used as operands
- without limitations.
- Searches may span multiple databases.
- </para>
-
- <para>
- The server has full support for piggy-backed present requests (see
- also the following section).
- </para>
-
- <para>
- <emphasis>Use</emphasis> attributes are interpreted according to the
- attribute sets which have been loaded in the
- <literal>zebra.cfg</literal> file, and are matched against specific
- fields as specified in the <literal>.abs</literal> 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.
- </para>
-
- <para>
- If a <emphasis>Structure</emphasis> attribute of
- <emphasis>Phrase</emphasis> is used in conjunction with a
- <emphasis>Completeness</emphasis> attribute of
- <emphasis>Complete (Sub)field</emphasis>, the term is matched
- against the contents of the phrase (long word) register, if one
- exists for the given <emphasis>Use</emphasis> attribute.
- A phrase register is created for those fields in the
- <literal>.abs</literal> file that contains a
- <literal>p</literal>-specifier.
- </para>
-
- <para>
- If <emphasis>Structure</emphasis>=<emphasis>Phrase</emphasis> is
- used in conjunction with <emphasis>Incomplete Field</emphasis> - the
- default value for <emphasis>Completeness</emphasis>, the
- search is directed against the normal word registers, but if the term
- contains multiple words, the term will only match if all of the words
- are found immediately adjacent, and in the given order.
- The word search is performed on those fields that are indexed as
- type <literal>w</literal> in the <literal>.abs</literal> file.
- </para>
-
- <para>
- If the <emphasis>Structure</emphasis> attribute is
- <emphasis>Word List</emphasis>,
- <emphasis>Free-form Text</emphasis>, or
- <emphasis>Document Text</emphasis>, the term is treated as a
- natural-language, relevance-ranked query.
- This search type uses the word register, i.e. those fields
- that are indexed as type <literal>w</literal> in the
- <literal>.abs</literal> file.
- </para>
-
- <para>
- If the <emphasis>Structure</emphasis> attribute is
- <emphasis>Numeric String</emphasis> the term is treated as an integer.
- The search is performed on those fields that are indexed
- as type <literal>n</literal> in the <literal>.abs</literal> file.
- </para>
-
- <para>
- If the <emphasis>Structure</emphasis> attribute is
- <emphasis>URx</emphasis> the term is treated as a URX (URL) entity.
- The search is performed on those fields that are indexed as type
- <literal>u</literal> in the <literal>.abs</literal> file.
- </para>
-
- <para>
- If the <emphasis>Structure</emphasis> attribute is
- <emphasis>Local Number</emphasis> the term is treated as
- native Zebra Record Identifier.
- </para>
-
- <para>
- If the <emphasis>Relation</emphasis> attribute is
- <emphasis>Equals</emphasis> (default), the term is matched
- in a normal fashion (modulo truncation and processing of
- individual words, if required).
- If <emphasis>Relation</emphasis> is <emphasis>Less Than</emphasis>,
- <emphasis>Less Than or Equal</emphasis>,
- <emphasis>Greater than</emphasis>, or <emphasis>Greater than or
- Equal</emphasis>, the term is assumed to be numerical, and a
- standard regular expression is constructed to match the given
- expression.
- If <emphasis>Relation</emphasis> is <emphasis>Relevance</emphasis>,
- the standard natural-language query processor is invoked.
- </para>
-
- <para>
- For the <emphasis>Truncation</emphasis> attribute,
- <emphasis>No Truncation</emphasis> is the default.
- <emphasis>Left Truncation</emphasis> is not supported.
- <emphasis>Process #</emphasis> is supported, as is
- <emphasis>Regxp-1</emphasis>.
- <emphasis>Regxp-2</emphasis> enables the fault-tolerant (fuzzy)
- search. As a default, a single error (deletion, insertion,
- replacement) is accepted when terms are matched against the register
- contents.
- </para>
-
- <sect3>
- <title>Regular expressions</title>
-
- <para>
- Each term in a query is interpreted as a regular expression if
- the truncation value is either <emphasis>Regxp-1</emphasis> (102)
- or <emphasis>Regxp-2</emphasis> (103).
- Both query types follow the same syntax with the operands:
- <variablelist>
-
- <varlistentry>
- <term>x</term>
- <listitem>
- <para>
- Matches the character <emphasis>x</emphasis>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>.</term>
- <listitem>
- <para>
- Matches any character.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><literal>[</literal>..<literal>]</literal></term>
- <listitem>
- <para>
- Matches the set of characters specified;
- such as <literal>[abc]</literal> or <literal>[a-c]</literal>.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- and the operators:
- <variablelist>
-
- <varlistentry>
- <term>x*</term>
- <listitem>
- <para>
- Matches <emphasis>x</emphasis> zero or more times. Priority: high.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>x+</term>
- <listitem>
- <para>
- Matches <emphasis>x</emphasis> one or more times. Priority: high.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>x?</term>
- <listitem>
- <para>
- Matches <emphasis>x</emphasis> once or twice. Priority: high.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>xy</term>
- <listitem>
- <para>
- Matches <emphasis>x</emphasis>, then <emphasis>y</emphasis>.
- Priority: medium.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>x|y</term>
- <listitem>
- <para>
- Matches either <emphasis>x</emphasis> or <emphasis>y</emphasis>.
- Priority: low.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- The order of evaluation may be changed by using parentheses.
- </para>
-
- <para>
- If the first character of the <emphasis>Regxp-2</emphasis> query
- is a plus character (<literal>+</literal>) it marks the
- beginning of a section with non-standard specifiers.
- The next plus character marks the end of the section.
- Currently Zebra only supports one specifier, the error tolerance,
- which consists one digit.
- </para>
-
- <para>
- Since the plus operator is normally a suffix operator the addition to
- the query syntax doesn't violate the syntax for standard regular
- expressions.
- </para>
-
- </sect3>
-
- <sect3>
- <title>Query examples</title>
-
- <para>
- Phrase search for <emphasis>information retrieval</emphasis> in
- the title-register:
- <screen>
- @attr 1=4 "information retrieval"
- </screen>
- </para>
-
- <para>
- Ranked search for the same thing:
- <screen>
- @attr 1=4 @attr 2=102 "Information retrieval"
- </screen>
- </para>
-
- <para>
- Phrase search with a regular expression:
- <screen>
- @attr 1=4 @attr 5=102 "informat.* retrieval"
- </screen>
- </para>
-
- <para>
- Ranked search with a regular expression:
- <screen>
- @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval"
- </screen>
- </para>
-
- <para>
- In the GILS schema (<literal>gils.abs</literal>), the
- west-bounding-coordinate is indexed as type <literal>n</literal>,
- and is therefore searched by specifying
- <emphasis>structure</emphasis>=<emphasis>Numeric String</emphasis>.
- To match all those records with west-bounding-coordinate greater
- than -114 we use the following query:
- <screen>
- @attr 4=109 @attr 2=5 @attr gils 1=2038 -114
- </screen>
- </para>
- </sect3>
- </sect2>
-
- <sect2>
- <title>Present</title>
- <para>
- The present facility is supported in a standard fashion. The requested
- record syntax is matched against the ones supported by the profile of
- each record retrieved. If no record syntax is given, SUTRS is the
- default. The requested element set name, again, is matched against any
- provided by the relevant record profiles.
- </para>
- </sect2>
- <sect2>
- <title>Scan</title>
- <para>
- The attribute combinations provided with the termListAndStartPoint are
- processed in the same way as operands in a query (see above).
- Currently, only the term and the globalOccurrences are returned with
- the termInfo structure.
- </para>
- </sect2>
- <sect2>
- <title>Sort</title>
-
- <para>
- Z39.50 specifies three diffent types of sort criterias.
- Of these Zebra supports the attribute specification type in which
- case the use attribute specifies the "Sort register".
- Sort registers are created for those fields that are of type "sort" in
- the default.idx file.
- The corresponding character mapping file in default.idx specifies the
- ordinal of each character used in the actual sort.
- </para>
-
- <para>
- Z39.50 allows the client to specify sorting on one or more input
- result sets and one output result set.
- Zebra supports sorting on one result set only which may or may not
- be the same as the output result set.
- </para>
- </sect2>
- <sect2>
- <title>Close</title>
- <para>
- If a Close PDU is received, the server will respond with a Close PDU
- with reason=FINISHED, no matter which protocol version was negotiated
- during initialization. If the protocol version is 3 or more, the
- server will generate a Close PDU under certain circumstances,
- including a session timeout (60 minutes by default), and certain kinds of
- protocol errors. Once a Close PDU has been sent, the protocol
- association is considered broken, and the transport connection will be
- closed immediately upon receipt of further data, or following a short
- timeout.
- </para>
- </sect2>
- </sect1>
-</chapter>
-
-<chapter id="record-model">
- <title>The Record Model</title>
-
- <para>
- The Zebra system is designed to support a wide range of data management
- applications. The system can be configured to handle virtually any
- kind of structured data. Each record in the system is associated with
- a <emphasis>record schema</emphasis> which lends context to the data
- elements of the record.
- Any number of record schema can coexist in the system.
- Although it may be wise to use only a single schema within
- one database, the system poses no such restrictions.
- </para>
-
- <para>
- The record model described in this chapter applies to the fundamental,
- structured
- record type <literal>grs</literal> as introduced in
- section <xref linkend="record-types"/>.
- </para>
-
- <para>
- Records pass through three different states during processing in the
- system.
- </para>
-
- <para>
-
- <itemizedlist>
- <listitem>
-
- <para>
- When records are accessed by the system, they are represented
- in their local, or native format. This might be SGML or HTML files,
- News or Mail archives, MARC records. If the system doesn't already
- know how to read the type of data you need to store, you can set up an
- input filter by preparing conversion rules based on regular
- expressions and possibly augmented by a flexible scripting language
- (Tcl).
- The input filter produces as output an internal representation:
-
- </para>
- </listitem>
- <listitem>
-
- <para>
- When records are processed by the system, they are represented
- in a tree-structure, constructed by tagged data elements hanging off a
- root node. The tagged elements may contain data or yet more tagged
- elements in a recursive structure. The system performs various
- actions on this tree structure (indexing, element selection, schema
- mapping, etc.),
-
- </para>
- </listitem>
- <listitem>
-
- <para>
- Before transmitting records to the client, they are first
- converted from the internal structure to a form suitable for exchange
- over the network - according to the Z39.50 standard.
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
-
- <sect1 id="local-representation">
- <title>Local Representation</title>
-
- <para>
- As mentioned earlier, Zebra places few restrictions on the type of
- data that you can index and manage. Generally, whatever the form of
- the data, it is parsed by an input filter specific to that format, and
- turned into an internal structure that Zebra knows how to handle. This
- process takes place whenever the record is accessed - for indexing and
- retrieval.
- </para>
-
- <para>
- The RecordType parameter in the <literal>zebra.cfg</literal> file, or
- the <literal>-t</literal> option to the indexer tells Zebra how to
- process input records.
- Two basic types of processing are available - raw text and structured
- data. Raw text is just that, and it is selected by providing the
- argument <emphasis>text</emphasis> to Zebra. Structured records are
- all handled internally using the basic mechanisms described in the
- subsequent sections.
- Zebra can read structured records in many different formats.
- How this is done is governed by additional parameters after the
- "grs" keyboard, separated by "." characters.
- </para>
-
- <para>
- Three basic subtypes to the <emphasis>grs</emphasis> type are
- currently available:
- </para>
-
- <para>
- <variablelist>
- <varlistentry>
- <term>grs.sgml</term>
- <listitem>
- <para>
- This is the canonical input format —
- described below. It is a simple SGML-like syntax.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>grs.regx.<emphasis>filter</emphasis></term>
- <listitem>
- <para>
- This enables a user-supplied input
- filter. The mechanisms of these filters are described below.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>grs.marc.<emphasis>abstract syntax</emphasis></term>
- <listitem>
- <para>
- This allows Zebra to read
- records in the ISO2709 (MARC) encoding standard. In this case, the
- last paramemeter <emphasis>abstract syntax</emphasis> names the
- <literal>.abs</literal> file (see below)
- which describes the specific MARC structure of the input record as
- well as the indexing rules.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
-
- <sect2>
- <title>Canonical Input Format</title>
-
- <para>
- Although input data can take any form, it is sometimes useful to
- describe the record processing capabilities of the system in terms of
- a single, canonical input format that gives access to the full
- spectrum of structure and flexibility in the system. In Zebra, this
- canonical format is an "SGML-like" syntax.
- </para>
-
- <para>
- To use the canonical format specify <literal>grs.sgml</literal> as
- the record type.
- </para>
-
- <para>
- Consider a record describing an information resource (such a record is
- sometimes known as a <emphasis>locator record</emphasis>).
- It might contain a field describing the distributor of the
- information resource, which might in turn be partitioned into
- various fields providing details about the distributor, like this:
- </para>
-
- <para>
-
- <screen>
- <Distributor>
- <Name> USGS/WRD </Name>
- <Organization> USGS/WRD </Organization>
- <Street-Address>
- U.S. GEOLOGICAL SURVEY, 505 MARQUETTE, NW
- </Street-Address>
- <City> ALBUQUERQUE </City>
- <State> NM </State>
- <Zip-Code> 87102 </Zip-Code>
- <Country> USA </Country>
- <Telephone> (505) 766-5560 </Telephone>
- </Distributor>
- </screen>
-
- </para>
-
- <note>
- <para>
- 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.
- </para>
- </note>
- <para>
- The keywords surrounded by <...> are
- <emphasis>tags</emphasis>, while the sections of text
- in between are the <emphasis>data elements</emphasis>.
- A data element is characterized by its location in the tree
- that is made up by the nested elements.
- Each element is terminated by a closing tag - beginning
- with <literal><</literal>/, and containing the same symbolic
- tag-name as the corresponding opening tag.
- The general closing tag - <literal><</literal>>/ -
- terminates the element started by the last opening tag. The
- structuring of elements is significant.
- The element <emphasis>Telephone</emphasis>,
- for instance, may be indexed and presented to the client differently,
- depending on whether it appears inside the
- <emphasis>Distributor</emphasis> element, or some other,
- structured data element such a <emphasis>Supplier</emphasis> element.
- </para>
-
- <sect3>
- <title>Record Root</title>
-
- <para>
- The first tag in a record describes the root node of the tree that
- makes up the total record. In the canonical input format, the root tag
- should contain the name of the schema that lends context to the
- elements of the record (see section
- <xref linkend="internal-representation"/>).
- The following is a GILS record that
- contains only a single element (strictly speaking, that makes it an
- illegal GILS record, since the GILS profile includes several mandatory
- elements - Zebra does not validate the contents of a record against
- the Z39.50 profile, however - it merely attempts to match up elements
- of a local representation with the given schema):
- </para>
-
- <para>
-
- <screen>
- <gils>
- <title>Zen and the Art of Motorcycle Maintenance</title>
- </gils>
- </screen>
-
- </para>
-
- </sect3>
-
- <sect3>
- <title>Variants</title>
-
- <para>
- Zebra allows you to provide individual data elements in a number of
- <emphasis>variant forms</emphasis>. Examples of variant forms are
- textual data elements which might appear in different languages, and
- images which may appear in different formats or layouts.
- The variant system in Zebra is essentially a representation of
- the variant mechanism of Z39.50-1995.
- </para>
-
- <para>
- The following is an example of a title element which occurs in two
- different languages.
- </para>
-
- <para>
-
- <screen>
- <title>
- <var lang lang "eng">
- Zen and the Art of Motorcycle Maintenance</>
- <var lang lang "dan">
- Zen og Kunsten at Vedligeholde en Motorcykel</>
- </title>
- </screen>
-
- </para>
-
- <para>
- The syntax of the <emphasis>variant element</emphasis> is
- <literal><var class type value></literal>.
- The available values for the <emphasis>class</emphasis> and
- <emphasis>type</emphasis> fields are given by the variant set
- that is associated with the current schema
- (see section <xref linkend="variant-set"/>).
- </para>
-
- <para>
- Variant elements are terminated by the general end-tag </>, by
- the variant end-tag </var>, by the appearance of another variant
- tag with the same <emphasis>class</emphasis> and
- <emphasis>value</emphasis> settings, or by the
- appearance of another, normal tag. In other words, the end-tags for
- the variants used in the example above could have been saved.
- </para>
-
- <para>
- Variant elements can be nested. The element
- </para>
-
- <para>
-
- <screen>
- <title>
- <var lang lang "eng"><var body iana "text/plain">
- Zen and the Art of Motorcycle Maintenance
- </title>
- </screen>
-
- </para>
-
- <para>
- Associates two variant components to the variant list for the title
- element.
- </para>
-
- <para>
- Given the nesting rules described above, we could write
- </para>
-
- <para>
-
- <screen>
- <title>
- <var body iana "text/plain>
- <var lang lang "eng">
- Zen and the Art of Motorcycle Maintenance
- <var lang lang "dan">
- Zen og Kunsten at Vedligeholde en Motorcykel
- </title>
- </screen>
-
- </para>
-
- <para>
- The title element above comes in two variants. Both have the IANA body
- type "text/plain", but one is in English, and the other in
- Danish. The client, using the element selection mechanism of Z39.50,
- can retrieve information about the available variant forms of data
- elements, or it can select specific variants based on the requirements
- of the end-user.
- </para>
-
- </sect3>
-
- </sect2>
-
- <sect2>
- <title>Input Filters</title>
-
- <para>
- In order to handle general input formats, Zebra allows the
- operator to define filters which read individual records in their
- native format and produce an internal representation that the system
- can work with.
- </para>
-
- <para>
- Input filters are ASCII files, generally with the suffix
- <literal>.flt</literal>.
- The system looks for the files in the directories given in the
- <emphasis>profilePath</emphasis> setting in the
- <literal>zebra.cfg</literal> files.
- The record type for the filter is
- <literal>grs.regx.</literal><emphasis>filter-filename</emphasis>
- (fundamental type <literal>grs</literal>, file read
- type <literal>regx</literal>, argument
- <emphasis>filter-filename</emphasis>).
- </para>
-
- <para>
- Generally, an input filter consists of a sequence of rules, where each
- rule consists of a sequence of expressions, followed by an action. The
- expressions are evaluated against the contents of the input record,
- and the actions normally contribute to the generation of an internal
- representation of the record.
- </para>
-
- <para>
- An expression can be either of the following:
- </para>
-
- <para>
- <variablelist>
-
- <varlistentry>
- <term>INIT</term>
- <listitem>
- <para>
- The action associated with this expression is evaluated
- exactly once in the lifetime of the application, before any records
- are read. It can be used in conjunction with an action that
- initializes tables or other resources that are used in the processing
- of input records.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>BEGIN</term>
- <listitem>
- <para>
- Matches the beginning of the record. It can be used to
- initialize variables, etc. Typically, the
- <emphasis>BEGIN</emphasis> rule is also used
- to establish the root node of the record.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>END</term>
- <listitem>
- <para>
- Matches the end of the record - when all of the contents
- of the record has been processed.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>/pattern/</term>
- <listitem>
- <para>
- Matches a string of characters from the input record.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>BODY</term>
- <listitem>
- <para>
- This keyword may only be used between two patterns.
- It matches everything between (not including) those patterns.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>FINISH</term>
- <listitem>
- <para>
- The expression asssociated with this pattern is evaluated
- once, before the application terminates. It can be used to release
- system resources - typically ones allocated in the
- <emphasis>INIT</emphasis> step.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
-
- <para>
- An action is surrounded by curly braces ({...}), and
- consists of a sequence of statements. Statements may be separated
- by newlines or semicolons (;).
- Within actions, the strings that matched the expressions
- immediately preceding the action can be referred to as
- $0, $1, $2, etc.
- </para>
-
- <para>
- The available statements are:
- </para>
-
- <para>
- <variablelist>
-
- <varlistentry>
- <term>begin <emphasis>type [parameter ... ]</emphasis></term>
- <listitem>
- <para>
- Begin a new
- data element. The type is one of the following:
- <variablelist>
-
- <varlistentry>
- <term>record</term>
- <listitem>
- <para>
- Begin a new record. The followingparameter should be the
- name of the schema that describes the structure of the record, eg.
- <literal>gils</literal> or <literal>wais</literal> (see below).
- The <literal>begin record</literal> call should precede
- any other use of the <emphasis>begin</emphasis> statement.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>element</term>
- <listitem>
- <para>
- Begin a new tagged element. The parameter is the
- name of the tag. If the tag is not matched anywhere in the tagsets
- referenced by the current schema, it is treated as a local string
- tag.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>variant</term>
- <listitem>
- <para>
- Begin a new node in a variant tree. The parameters are
- <emphasis>class type value</emphasis>.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>data</term>
- <listitem>
- <para>
- Create a data element. The concatenated arguments make
- up the value of the data element.
- The option <literal>-text</literal> signals that
- the layout (whitespace) of the data should be retained for
- transmission.
- The option <literal>-element</literal>
- <emphasis>tag</emphasis> wraps the data up in
- the <emphasis>tag</emphasis>.
- The use of the <literal>-element</literal> option is equivalent to
- preceding the command with a <emphasis>begin
- element</emphasis> command, and following
- it with the <emphasis>end</emphasis> command.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>end <emphasis>[type]</emphasis></term>
- <listitem>
- <para>
- Close a tagged element. If no parameter is given,
- the last element on the stack is terminated.
- The first parameter, if any, is a type name, similar
- to the <emphasis>begin</emphasis> statement.
- For the <emphasis>element</emphasis> type, a tag
- name can be provided to terminate a specific tag.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
-
- <para>
- The following input filter reads a Usenet news file, producing a
- record in the WAIS schema. Note that the body of a news posting is
- separated from the list of headers by a blank line (or rather a
- sequence of two newline characters.
- </para>
-
- <para>
-
- <screen>
- BEGIN { begin record wais }
-
- /^From:/ BODY /$/ { data -element name $1 }
- /^Subject:/ BODY /$/ { data -element title $1 }
- /^Date:/ BODY /$/ { data -element lastModified $1 }
- /\n\n/ BODY END {
- begin element bodyOfDisplay
- begin variant body iana "text/plain"
- data -text $1
- end record
- }
- </screen>
-
- </para>
-
- <para>
- If Zebra is compiled with support for Tcl (Tool Command Language)
- enabled, the statements described above are supplemented with a complete
- scripting environment, including control structures (conditional
- expressions and loop constructs), and powerful string manipulation
- mechanisms for modifying the elements of a record. Tcl is a popular
- scripting environment, with several tutorials available both online
- and in hardcopy.
- </para>
-
- <para>
- <emphasis>NOTE: Tcl support is not currently available, but will be
- included with one of the next alpha or beta releases.</emphasis>
- </para>
-
- <para>
- <emphasis>NOTE: Variant support is not currently available in the input
- filter, but will be included with one of the next alpha or beta
- releases.</emphasis>
- </para>
-
- </sect2>
-
- </sect1>
-
- <sect1 id="internal-representation">
- <title>Internal Representation</title>
-
- <para>
- When records are manipulated by the system, they're represented in a
- tree-structure, with data elements at the leaf nodes, and tags or
- variant components at the non-leaf nodes. The root-node identifies the
- schema that lends context to the tagging and structuring of the
- record. Imagine a simple record, consisting of a 'title' element and
- an 'author' element:
- </para>
-
- <para>
-
- <screen>
- TITLE "Zen and the Art of Motorcycle Maintenance"
- ROOT
- AUTHOR "Robert Pirsig"
- </screen>
-
- </para>
-
- <para>
- A slightly more complex record would have the author element consist
- of two elements, a surname and a first name:
- </para>
-
- <para>
-
- <screen>
- TITLE "Zen and the Art of Motorcycle Maintenance"
- ROOT
- FIRST-NAME "Robert"
- AUTHOR
- SURNAME "Pirsig"
- </screen>
-
- </para>
-
- <para>
- The root of the record will refer to the record schema that describes
- the structuring of this particular record. The schema defines the
- element tags (TITLE, FIRST-NAME, etc.) that may occur in the record, as
- well as the structuring (SURNAME should appear below AUTHOR, etc.). In
- addition, the schema establishes element set names that are used by
- the client to request a subset of the elements of a given record. The
- schema may also establish rules for converting the record to a
- different schema, by stating, for each element, a mapping to a
- different tag path.
- </para>
-
- <sect2>
- <title>Tagged Elements</title>
-
- <para>
- A data element is characterized by its tag, and its position in the
- structure of the record. For instance, while the tag "telephone
- number" may be used different places in a record, we may need to
- distinguish between these occurrences, both for searching and
- presentation purposes. For instance, while the phone numbers for the
- "customer" and the "service provider" are both
- representatives for the same type of resource (a telephone number), it
- is essential that they be kept separate. The record schema provides
- the structure of the record, and names each data element (defined by
- the sequence of tags - the tag path - by which the element can be
- reached from the root of the record).
- </para>
-
- </sect2>
-
- <sect2>
- <title>Variants</title>
-
- <para>
- The children of a tag node may be either more tag nodes, a data node
- (possibly accompanied by tag nodes),
- or a tree of variant nodes. The children of variant nodes are either
- more variant nodes or a data node (possibly accompanied by more
- variant nodes). Each leaf node, which is normally a
- data node, corresponds to a <emphasis>variant form</emphasis> of the
- tagged element identified by the tag which parents the variant tree.
- The following title element occurs in two different languages:
- </para>
-
- <para>
-
- <screen>
- VARIANT LANG=ENG "War and Peace"
- TITLE
- VARIANT LANG=DAN "Krig og Fred"
- </screen>
-
- </para>
-
- <para>
- Which of the two elements are transmitted to the client by the server
- depends on the specifications provided by the client, if any.
- </para>
-
- <para>
- In practice, each variant node is associated with a triple of class,
- type, value, corresponding to the variant mechanism of Z39.50.
- </para>
-
- </sect2>
-
- <sect2>
- <title>Data Elements</title>
-
- <para>
- Data nodes have no children (they are always leaf nodes in the record
- tree).
- </para>
-
- <note>
- <para>
- Documentation needs extension here about types of nodes - numerical,
- textual, etc., plus the various types of inclusion notes.
- </para>
- </note>
-
- </sect2>
-
- </sect1>
-
- <sect1 id="data-model">
- <title>Configuring Your Data Model</title>
-
- <para>
- The following sections describe the configuration files that govern
- the internal management of data records. The system searches for the files
- in the directories specified by the <emphasis>profilePath</emphasis>
- setting in the <literal>zebra.cfg</literal> file.
- </para>
-
- <sect2>
- <title>The Abstract Syntax</title>
-
- <para>
- The abstract syntax definition (also known as an Abstract Record
- Structure, or ARS) is the focal point of the
- record schema description. For a given schema, the ABS file may state any
- or all of the following:
- </para>
-
- <para>
-
- <itemizedlist>
- <listitem>
-
- <para>
- The object identifier of the Z39.50 schema associated
- with the ARS, so that it can be referred to by the client.
- </para>
- </listitem>
-
- <listitem>
- <para>
- The attribute set (which can possibly be a compound of multiple
- sets) which applies in the profile. This is used when indexing and
- searching the records belonging to the given profile.
- </para>
- </listitem>
-
- <listitem>
- <para>
- The Tag set (again, this can consist of several different sets).
- This is used when reading the records from a file, to recognize the
- different tags, and when transmitting the record to the client -
- mapping the tags to their numerical representation, if they are
- known.
- </para>
- </listitem>
-
- <listitem>
- <para>
- The variant set which is used in the profile. This provides a
- vocabulary for specifying the <emphasis>forms</emphasis> of data that appear inside
- the records.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Element set names, which are a shorthand way for the client to
- ask for a subset of the data elements contained in a record. Element
- set names, in the retrieval module, are mapped to <emphasis>element
- specifications</emphasis>, which contain information equivalent to the
- <emphasis>Espec-1</emphasis> syntax of Z39.50.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Map tables, which may specify mappings to
- <emphasis>other</emphasis> database profiles, if desired.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Possibly, a set of rules describing the mapping of elements to a
- MARC representation.
-
- </para>
- </listitem>
-
- <listitem>
- <para>
- A list of element descriptions (this is the actual ARS of the
- schema, in Z39.50 terms), which lists the ways in which the various
- tags can be used and organized hierarchically.
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
-
- <para>
- Several of the entries above simply refer to other files, which
- describe the given objects.
- </para>
-
- </sect2>
-
- <sect2>
- <title>The Configuration Files</title>
-
- <para>
- This section describes the syntax and use of the various tables which
- are used by the retrieval module.
- </para>
-
- <para>
- The number of different file types may appear daunting at first, but
- each type corresponds fairly clearly to a single aspect of the Z39.50
- retrieval facilities. Further, the average database administrator,
- who is simply reusing an existing profile for which tables already
- exist, shouldn't have to worry too much about the contents of these tables.
- </para>
-
- <para>
- Generally, the files are simple ASCII files, which can be maintained
- using any text editor. Blank lines, and lines beginning with a (#) are
- ignored. Any characters on a line followed by a (#) are also ignored.
- All other lines contain <emphasis>directives</emphasis>, which provide
- some setting or value to the system.
- Generally, settings are characterized by a single
- keyword, identifying the setting, followed by a number of parameters.
- Some settings are repeatable (r), while others may occur only once in a
- file. Some settings are optional (o), whicle others again are
- mandatory (m).
- </para>
-
- </sect2>
-
- <sect2>
- <title>The Abstract Syntax (.abs) Files</title>
-
- <para>
- The name of this file type is slightly misleading in Z39.50 terms,
- since, apart from the actual abstract syntax of the profile, it also
- includes most of the other definitions that go into a database
- profile.
- </para>
-
- <para>
- When a record in the canonical, SGML-like format is read from a file
- or from the database, the first tag of the file should reference the
- profile that governs the layout of the record. If the first tag of the
- record is, say, <literal><gils></literal>, the system will look
- for the profile definition in the file <literal>gils.abs</literal>.
- Profile definitions are cached, so they only have to be read once
- during the lifespan of the current process.
- </para>
-
- <para>
- When writing your own input filters, the
- <emphasis>record-begin</emphasis> command
- introduces the profile, and should always be called first thing when
- introducing a new record.
- </para>
-
- <para>
- The file may contain the following directives:
- </para>
-
- <para>
- <variablelist>
-
- <varlistentry>
- <term>name <emphasis>symbolic-name</emphasis></term>
- <listitem>
- <para>
- (m) This provides a shorthand name or
- description for the profile. Mostly useful for diagnostic purposes.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>reference <emphasis>OID-name</emphasis></term>
- <listitem>
- <para>
- (m) The reference name of the OID for the profile.
- The reference names can be found in the <emphasis>util</emphasis>
- module of <emphasis>YAZ</emphasis>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>attset <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- (m) The attribute set that is used for
- indexing and searching records belonging to this profile.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>tagset <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- (o) The tag set (if any) that describe
- that fields of the records.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>varset <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- (o) The variant set used in the profile.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>maptab <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- (o,r) This points to a
- conversion table that might be used if the client asks for the record
- in a different schema from the native one.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>marc <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- (o) Points to a file containing parameters
- for representing the record contents in the ISO2709 syntax. Read the
- description of the MARC representation facility below.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>esetname <emphasis>name filename</emphasis></term>
- <listitem>
- <para>
- (o,r) Associates the
- given element set name with an element selection file. If an (@) is
- given in place of the filename, this corresponds to a null mapping for
- the given element set name.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>any <emphasis>tags</emphasis></term>
- <listitem>
- <para>
- (o) This directive specifies a list of attributes
- which should be appended to the attribute list given for each
- element. The effect is to make every single element in the abstract
- syntax searchable by way of the given attributes. This directive
- provides an efficient way of supporting free-text searching across all
- elements. However, it does increase the size of the index
- significantly. The attributes can be qualified with a structure, as in
- the <emphasis>elm</emphasis> directive below.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>elm <emphasis>path name attributes</emphasis></term>
- <listitem>
- <para>
- (o,r) Adds an element to the abstract record syntax of the schema.
- The <emphasis>path</emphasis> follows the
- syntax which is suggested by the Z39.50 document - that is, a sequence
- of tags separated by slashes (/). Each tag is given as a
- comma-separated pair of tag type and -value surrounded by parenthesis.
- The <emphasis>name</emphasis> is the name of the element, and
- the <emphasis>attributes</emphasis>
- specifies which attributes to use when indexing the element in a
- comma-separated list.
- A ! in place of the attribute name is equivalent to
- specifying an attribute name identical to the element name.
- A - in place of the attribute name
- specifies that no indexing is to take place for the given element.
- The attributes can be qualified with <emphasis>field
- types</emphasis> to specify which
- character set should govern the indexing procedure for that field.
- The same data element may be indexed into several different
- fields, using different character set definitions.
- See the section <xref linkend="field-structure-and-character-sets"/>.
- The default field type is "w" for <emphasis>word</emphasis>.
- </para>
- </listitem></varlistentry>
- </variablelist>
- </para>
-
- <note>
- <para>
- The mechanism for controlling indexing is not adequate for
- complex databases, and will probably be moved into a separate
- configuration table eventually.
- </para>
- </note>
-
- <para>
- The following is an excerpt from the abstract syntax file for the GILS
- profile.
- </para>
-
- <para>
-
- <screen>
- name gils
- reference GILS-schema
- attset gils.att
- tagset gils.tag
- varset var1.var
-
- maptab gils-usmarc.map
-
- # Element set names
-
- esetname VARIANT gils-variant.est # for WAIS-compliance
- esetname B gils-b.est
- esetname G gils-g.est
- esetname F @
-
- elm (1,10) rank -
- elm (1,12) url -
- elm (1,14) localControlNumber Local-number
- elm (1,16) dateOfLastModification Date/time-last-modified
- elm (2,1) title w:!,p:!
- elm (4,1) controlIdentifier Identifier-standard
- elm (2,6) abstract Abstract
- elm (4,51) purpose !
- elm (4,52) originator -
- elm (4,53) accessConstraints !
- elm (4,54) useConstraints !
- elm (4,70) availability -
- elm (4,70)/(4,90) distributor -
- elm (4,70)/(4,90)/(2,7) distributorName !
- elm (4,70)/(4,90)/(2,10 distributorOrganization !
- elm (4,70)/(4,90)/(4,2) distributorStreetAddress !
- elm (4,70)/(4,90)/(4,3) distributorCity !
- </screen>
-
- </para>
-
- </sect2>
-
- <sect2 id="attset-files">
- <title>The Attribute Set (.att) Files</title>
-
- <para>
- This file type describes the <emphasis>Use</emphasis> elements of
- an attribute set.
- It contains the following directives.
- </para>
-
- <para>
- <variablelist>
- <varlistentry>
- <term>name <emphasis>symbolic-name</emphasis></term>
- <listitem>
- <para>
- (m) This provides a shorthand name or
- description for the attribute set.
- Mostly useful for diagnostic purposes.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>reference <emphasis>OID-name</emphasis></term>
- <listitem>
- <para>
- (m) The reference name of the OID for
- the attribute set.
- The reference names can be found in the <emphasis>util</emphasis>
- module of <emphasis>YAZ</emphasis>.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>include <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- (o,r) This directive is used to
- include another attribute set as a part of the current one. This is
- used when a new attribute set is defined as an extension to another
- set. For instance, many new attribute sets are defined as extensions
- to the <emphasis>bib-1</emphasis> set.
- This is an important feature of the retrieval
- system of Z39.50, as it ensures the highest possible level of
- interoperability, as those access points of your database which are
- derived from the external set (say, bib-1) can be used even by clients
- who are unaware of the new set.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>att
- <emphasis>att-value att-name [local-value]</emphasis></term>
- <listitem>
- <para>
- (o,r) This
- repeatable directive introduces a new attribute to the set. The
- attribute value is stored in the index (unless a
- <emphasis>local-value</emphasis> is
- given, in which case this is stored). The name is used to refer to the
- attribute from the <emphasis>abstract syntax</emphasis>.
- </para>
- </listitem></varlistentry>
- </variablelist>
- </para>
-
- <para>
- This is an excerpt from the GILS attribute set definition.
- Notice how the file describing the <emphasis>bib-1</emphasis>
- attribute set is referenced.
- </para>
-
- <para>
-
- <screen>
- name gils
- reference GILS-attset
- include bib1.att
-
- att 2001 distributorName
- att 2002 indextermsControlled
- att 2003 purpose
- att 2004 accessConstraints
- att 2005 useConstraints
- </screen>
-
- </para>
-
- </sect2>
-
- <sect2>
- <title>The Tag Set (.tag) Files</title>
-
- <para>
- This file type defines the tagset of the profile, possibly by
- referencing other tag sets (most tag sets, for instance, will include
- tagsetG and tagsetM from the Z39.50 specification. The file may
- contain the following directives.
- </para>
-
- <para>
- <variablelist>
-
- <varlistentry>
- <term>name <emphasis>symbolic-name</emphasis></term>
- <listitem>
- <para>
- (m) This provides a shorthand name or
- description for the tag set. Mostly useful for diagnostic purposes.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>reference <emphasis>OID-name</emphasis></term>
- <listitem>
- <para>
- (o) The reference name of the OID for the tag set.
- The reference names can be found in the <emphasis>util</emphasis>
- module of <emphasis>YAZ</emphasis>.
- The directive is optional, since not all tag sets
- are registered outside of their schema.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>type <emphasis>integer</emphasis></term>
- <listitem>
- <para>
- (m) The type number of the tagset within the schema
- profile (note: this specification really should belong to the .abs
- file. This will be fixed in a future release).
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>include <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- (o,r) This directive is used
- to include the definitions of other tag sets into the current one.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>tag <emphasis>number names type</emphasis></term>
- <listitem>
- <para>
- (o,r) Introduces a new tag to the set.
- The <emphasis>number</emphasis> is the tag number as used
- in the protocol (there is currently no mechanism for
- specifying string tags at this point, but this would be quick
- work to add).
- The <emphasis>names</emphasis> parameter is a list of names
- by which the tag should be recognized in the input file format.
- The names should be separated by slashes (/).
- The <emphasis>type</emphasis> is th recommended datatype of
- the tag.
- It should be one of the following:
-
- <itemizedlist>
- <listitem>
- <para>
- structured
- </para>
- </listitem>
-
- <listitem>
- <para>
- string
- </para>
- </listitem>
-
- <listitem>
- <para>
- numeric
- </para>
- </listitem>
-
- <listitem>
- <para>
- bool
- </para>
- </listitem>
-
- <listitem>
- <para>
- oid
- </para>
- </listitem>
-
- <listitem>
- <para>
- generalizedtime
- </para>
- </listitem>
- <listitem>
- <para>
- intunit
- </para>
- </listitem>
-
- <listitem>
- <para>
- int
- </para>
- </listitem>
-
- <listitem>
- <para>
- octetstring
- </para>
- </listitem>
-
- <listitem>
- <para>
- null
- </para>
- </listitem>
-
- </itemizedlist>
+ </sect2>
- </para>
- </listitem></varlistentry>
- </variablelist>
- </para>
- <para>
- The following is an excerpt from the TagsetG definition file.
- </para>
+ </sect1>
- <para>
+ <sect1 id="administration-extended-services">
+ <title>Extended Services: Remote Insert, Update and Delete</title>
+
+ <para>
+ The extended services are not enabled by default in zebra - due to the
+ fact that they modify the system.
+ In order to allow anybody to update, use
<screen>
- name tagsetg
- reference TagsetG
- type 2
-
- tag 1 title string
- tag 2 author string
- tag 3 publicationPlace string
- tag 4 publicationDate string
- tag 5 documentId string
- tag 6 abstract string
- tag 7 name string
- tag 8 date generalizedtime
- tag 9 bodyOfDisplay string
- tag 10 organization string
+ perm.anonymous: rw
</screen>
+ in the main zebra configuration file <filename>zebra.cfg</filename>.
+ Or, even better, allow only updates for a particular admin user. For
+ user <literal>admin</literal>, you could use:
+ <screen>
+ perm.admin: rw
+ passwd: passwordfile
+ </screen>
+ And in <filename>passwordfile</filename>, specify users and
+ passwords as colon seperated strings:
+ <screen>
+ admin:secret
+ </screen>
</para>
-
- </sect2>
-
- <sect2 id="variant-set">
- <title>The Variant Set (.var) Files</title>
-
- <para>
- The variant set file is a straightforward representation of the
- variant set definitions associated with the protocol. At present, only
- the <emphasis>Variant-1</emphasis> set is known.
- </para>
-
- <para>
- These are the directives allowed in the file.
- </para>
-
<para>
- <variablelist>
-
- <varlistentry>
- <term>name <emphasis>symbolic-name</emphasis></term>
- <listitem>
- <para>
- (m) This provides a shorthand name or
- description for the variant set. Mostly useful for diagnostic purposes.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>reference <emphasis>OID-name</emphasis></term>
- <listitem>
- <para>
- (o) The reference name of the OID for
- the variant set, if one is required. The reference names can be found
- in the <emphasis>util</emphasis> module of <emphasis>YAZ</emphasis>.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>class <emphasis>integer class-name</emphasis></term>
- <listitem>
- <para>
- (m,r) Introduces a new
- class to the variant set.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>type <emphasis>integer type-name datatype</emphasis></term>
- <listitem>
- <para>
- (m,r) Addes a
- new type to the current class (the one introduced by the most recent
- <emphasis>class</emphasis> directive).
- The type names belong to the same name space as the one used
- in the tag set definition file.
- </para>
- </listitem></varlistentry>
- </variablelist>
+ We can now start a yaz-client admin session and create a database:
+ <screen>
+ <![CDATA[
+ $ yaz-client localhost:9999 -u admin/secret
+ Z> adm-create
+ ]]>
+ </screen>
+ Now the <literal>Default</literal> database was created,
+ we can insert an XML file (esdd0006.grs
+ from example/gils/records) and index it:
+ <screen>
+ <![CDATA[
+ Z> update insert 1 esdd0006.grs
+ ]]>
+ </screen>
+ The 3rd parameter - <literal>1</literal> here -
+ is the opaque record ID from <literal>Ext update</literal>.
+ It a record ID that <emphasis>we</emphasis> assign to the record
+ in question. If we do not
+ assign one, the usual rules for match apply (recordId: from zebra.cfg).
</para>
-
<para>
- The following is an excerpt from the file describing the variant set
- <emphasis>Variant-1</emphasis>.
+ Actually, we should have a way to specify "no opaque record id" for
+ yaz-client's update command.. We'll fix that.
</para>
-
<para>
-
+ The newly inserted record can be searched as usual:
<screen>
- 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
+ <![CDATA[
+ Z> f utah
+ Sent searchRequest.
+ Received SearchResponse.
+ Search was a success.
+ Number of hits: 1, setno 1
+ SearchResult-1: term=utah cnt=1
+ records returned: 0
+ Elapsed: 0.014179
+ ]]>
</screen>
-
</para>
-
- </sect2>
-
- <sect2>
- <title>The Element Set (.est) Files</title>
-
<para>
- The element set specification files describe a selection of a subset
- of the elements of a database record. The element selection mechanism
- is equivalent to the one supplied by the <emphasis>Espec-1</emphasis>
- syntax of the Z39.50 specification.
- In fact, the internal representation of an element set
- specification is identical to the <emphasis>Espec-1</emphasis> structure,
- and we'll refer you to the description of that structure for most of
- the detailed semantics of the directives below.
- </para>
-
- <note>
- <para>
- 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.
+ Let's delete the beast:
+ <screen>
+ <![CDATA[
+ Z> update delete 1
+ No last record (update ignored)
+ Z> update delete 1 esdd0006.grs
+ Got extended services response
+ Status: done
+ Elapsed: 0.072441
+ Z> f utah
+ Sent searchRequest.
+ Received SearchResponse.
+ Search was a success.
+ Number of hits: 0, setno 2
+ SearchResult-1: term=utah cnt=0
+ records returned: 0
+ Elapsed: 0.013610
+ ]]>
+ </screen>
</para>
- </note>
-
- <para>
- The directives available in the element set file are as follows:
- </para>
-
- <para>
- <variablelist>
- <varlistentry>
- <term>defaultVariantSetId <emphasis>OID-name</emphasis></term>
- <listitem>
- <para>
- (o) If variants are used in
- the following, this should provide the name of the variantset used
- (it's not currently possible to specify a different set in the
- individual variant request). In almost all cases (certainly all
- profiles known to us), the name
- <literal>Variant-1</literal> should be given here.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>defaultVariantRequest <emphasis>variant-request</emphasis></term>
- <listitem>
- <para>
- (o) This directive
- provides a default variant request for
- use when the individual element requests (see below) do not contain a
- variant request. Variant requests consist of a blank-separated list of
- variant components. A variant compont is a comma-separated,
- parenthesized triple of variant class, type, and value (the two former
- values being represented as integers). The value can currently only be
- entered as a string (this will change to depend on the definition of
- the variant in question). The special value (@) is interpreted as a
- null value, however.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>simpleElement
- <emphasis>path ['variant' variant-request]</emphasis></term>
- <listitem>
- <para>
- (o,r) This corresponds to a simple element request
- in <emphasis>Espec-1</emphasis>.
- The path consists of a sequence of tag-selectors, where each of
- these can consist of either:
- </para>
-
- <para>
- <itemizedlist>
- <listitem>
- <para>
- A simple tag, consisting of a comma-separated type-value pair in
- parenthesis, possibly followed by a colon (:) followed by an
- occurrences-specification (see below). The tag-value can be a number
- or a string. If the first character is an apostrophe ('), this
- forces the value to be interpreted as a string, even if it
- appears to be numerical.
- </para>
- </listitem>
-
- <listitem>
- <para>
- A WildThing, represented as a question mark (?), possibly
- followed by a colon (:) followed by an occurrences
- specification (see below).
- </para>
- </listitem>
-
- <listitem>
- <para>
- A WildPath, represented as an asterisk (*). Note that the last
- element of the path should not be a wildPath (wildpaths don't
- work in this version).
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
-
- <para>
- The occurrences-specification can be either the string
- <literal>all</literal>, the string <literal>last</literal>, or
- an explicit value-range. The value-range is represented as
- an integer (the starting point), possibly followed by a
- plus (+) and a second integer (the number of elements, default
- being one).
- </para>
-
- <para>
- The variant-request has the same syntax as the defaultVariantRequest
- above. Note that it may sometimes be useful to give an empty variant
- request, simply to disable the default for a specific set of fields
- (we aren't certain if this is proper <emphasis>Espec-1</emphasis>,
- but it works in this implementation).
- </para>
- </listitem></varlistentry>
- </variablelist>
- </para>
-
- <para>
- The following is an example of an element specification belonging to
- the GILS profile.
- </para>
-
- <para>
-
+ <para>
+ If shadow register is enabled in your
+ <filename>zebra.cfg</filename>,
+ you must run the adm-commit command
<screen>
- simpleelement (1,10)
- simpleelement (1,12)
- simpleelement (2,1)
- simpleelement (1,14)
- simpleelement (4,1)
- simpleelement (4,52)
+ <![CDATA[
+ Z> adm-commit
+ ]]>
</screen>
-
- </para>
-
- </sect2>
-
- <sect2 id="schema-mapping">
- <title>The Schema Mapping (.map) Files</title>
-
- <para>
- Sometimes, the client might want to receive a database record in
- a schema that differs from the native schema of the record. For
- instance, a client might only know how to process WAIS records, while
- the database record is represented in a more specific schema, such as
- GILS. In this module, a mapping of data to one of the MARC formats is
- also thought of as a schema mapping (mapping the elements of the
- record into fields consistent with the given MARC specification, prior
- to actually converting the data to the ISO2709). This use of the
- object identifier for USMARC as a schema identifier represents an
- overloading of the OID which might not be entirely proper. However,
- it represents the dual role of schema and record syntax which
- is assumed by the MARC family in Z39.50.
- </para>
-
- <para>
- <emphasis>NOTE: The schema-mapping functions are so far limited to a
- straightforward mapping of elements. This should be extended with
- mechanisms for conversions of the element contents, and conditional
- mappings of elements based on the record contents.</emphasis>
- </para>
-
- <para>
- These are the directives of the schema mapping file format:
- </para>
-
- <para>
- <variablelist>
-
- <varlistentry>
- <term>targetName <emphasis>name</emphasis></term>
- <listitem>
- <para>
- (m) A symbolic name for the target schema
- of the table. Useful mostly for diagnostic purposes.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>targetRef <emphasis>OID-name</emphasis></term>
- <listitem>
- <para>
- (m) An OID name for the target schema.
- This is used, for instance, by a server receiving a request to present
- a record in a different schema from the native one.
- The name, again, is found in the <emphasis>oid</emphasis>
- module of <emphasis>YAZ</emphasis>.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>map <emphasis>element-name target-path</emphasis></term>
- <listitem>
- <para>
- (o,r) Adds
- an element mapping rule to the table.
- </para>
- </listitem></varlistentry>
- </variablelist>
- </para>
-
- </sect2>
-
- <sect2>
- <title>The MARC (ISO2709) Representation (.mar) Files</title>
-
- <para>
- This file provides rules for representing a record in the ISO2709
- format. The rules pertain mostly to the values of the constant-length
- header of the record.
- </para>
-
- <para>
- <emphasis>NOTE: This will be described better. We're in the process of
- re-evaluating and most likely changing the way that MARC records are
- handled by the system.</emphasis>
- </para>
-
- </sect2>
-
- <sect2 id="field-structure-and-character-sets">
- <title>Field Structure and Character Sets
- </title>
-
- <para>
- In order to provide a flexible approach to national character set
- handling, Zebra allows the administrator to configure the set up the
- system to handle any 8-bit character set — including sets that
- require multi-octet diacritics or other multi-octet characters. The
- definition of a character set includes a specification of the
- permissible values, their sort order (this affects the display in the
- SCAN function), and relationships between upper- and lowercase
- characters. Finally, the definition includes the specification of
- space characters for the set.
- </para>
-
- <para>
- The operator can define different character sets for different fields,
- typical examples being standard text fields, numerical fields, and
- special-purpose fields such as WWW-style linkages (URx).
- </para>
-
- <para>
- The field types, and hence character sets, are associated with data
- elements by the .abs files (see above).
- The file <literal>default.idx</literal>
- provides the association between field type codes (as used in the .abs
- files) and the character map files (with the .chr suffix). The format
- of the .idx file is as follows
+ after each update session in order write your changes from the
+ shadow to the life register space.
</para>
-
<para>
- <variablelist>
-
- <varlistentry>
- <term>index <emphasis>field type code</emphasis></term>
- <listitem>
- <para>
- This directive introduces a new search index code.
- The argument is a one-character code to be used in the
- .abs files to select this particular index type. An index, roughly,
- corresponds to a particular structure attribute during search. Refer
- to section <xref linkend="search"/>.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>sort <emphasis>field code type</emphasis></term>
- <listitem>
- <para>
- This directive introduces a
- sort index. The argument is a one-character code to be used in the
- .abs fie to select this particular index type. The corresponding
- use attribute must be used in the sort request to refer to this
- particular sort index. The corresponding character map (see below)
- is used in the sort process.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>completeness <emphasis>boolean</emphasis></term>
- <listitem>
- <para>
- This directive enables or disables complete field indexing.
- The value of the <emphasis>boolean</emphasis> should be 0
- (disable) or 1. If completeness is enabled, the index entry will
- contain the complete contents of the field (up to a limit), with words
- (non-space characters) separated by single space characters
- (normalized to " " on display). When completeness is
- disabled, each word is indexed as a separate entry. Complete subfield
- indexing is most useful for fields which are typically browsed (eg.
- titles, authors, or subjects), or instances where a match on a
- complete subfield is essential (eg. exact title searching). For fields
- where completeness is disabled, the search engine will interpret a
- search containing space characters as a word proximity search.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>charmap <emphasis>filename</emphasis></term>
- <listitem>
- <para>
- This is the filename of the character
- map to be used for this index for field type.
- </para>
- </listitem></varlistentry>
- </variablelist>
+ Extended services are also available from the YAZ client layer. An
+ example of an YAZ-PHP extended service transaction is given here:
+ <screen>
+ <![CDATA[
+ $record = '<record><title>A fine specimen of a record</title></record>';
+
+ $options = array('action' => 'recordInsert',
+ 'syntax' => 'xml',
+ 'record' => $record,
+ 'databaseName' => 'mydatabase'
+ );
+
+ yaz_es($yaz, 'update', $options);
+ yaz_es($yaz, 'commit', array());
+ yaz_wait();
+
+ if ($error = yaz_error($yaz))
+ echo "$error";
+ ]]>
+ </screen>
+ The <literal>action</literal> parameter can be any of
+ <literal>recordInsert</literal> (will fail if the record already exists),
+ <literal>recordReplace</literal> (will fail if the record does not exist),
+ <literal>recordDelete</literal> (will fail if the record does not
+ exist), and
+ <literal>specialUpdate</literal> (will insert or update the record
+ as needed).
+ </para>
+ <para>
+ If a record is inserted
+ using the action <literal>recordInsert</literal>
+ one can specify the optional
+ <literal>recordIdOpaque</literal> parameter, which is a
+ client-supplied, opaque record identifier. This identifier will
+ replace zebra's own automagic identifier generation.
+ </para>
+ <para>
+ When using the action <literal>recordReplace</literal> or
+ <literal>recordDelete</literal>, one must specify the additional
+ <literal>recordIdNumber</literal> parameter, which must be an
+ existing Zebra internal system ID number. When retrieving existing
+ records, the ID number is returned in the field
+ <literal>/*/id:idzebra/localnumber</literal> in the namespace
+ <literal>xmlns:id="http://www.indexdata.dk/zebra/"</literal>,
+ where it can be picked up for later record updates or deletes.
</para>
+ </sect1>
- <para>
- The contents of the character map files are structured as follows:
- </para>
+ <sect1 id="gfs-config">
+ <title>YAZ Frontend Virtual Hosts</title>
+ <para>
+ <command>zebrasrv</command> uses the YAZ server frontend and does
+ support multiple virtual servers behind multiple listening sockets.
+ </para>
+ &zebrasrv-virtual;
+
<para>
- <variablelist>
-
- <varlistentry>
- <term>lowercase <emphasis>value-set</emphasis></term>
- <listitem>
- <para>
- This directive introduces the basic value set of the field type.
- The format is an ordered list (without spaces) of the
- characters which may occur in "words" of the given type.
- The order of the entries in the list determines the
- sort order of the index. In addition to single characters, the
- following combinations are legal:
- </para>
-
- <para>
-
- <itemizedlist>
- <listitem>
- <para>
- Backslashes may be used to introduce three-digit octal, or
- two-digit hex representations of single characters
- (preceded by <literal>x</literal>).
- In addition, the combinations
- \\, \\r, \\n, \\t, \\s (space — remember that real
- space-characters may ot occur in the value definition), and
- \\ are recognised, with their usual interpretation.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Curly braces {} may be used to enclose ranges of single
- characters (possibly using the escape convention described in the
- preceding point), eg. {a-z} to entroduce the
- standard range of ASCII characters.
- Note that the interpretation of such a range depends on
- the concrete representation in your local, physical character set.
- </para>
- </listitem>
-
- <listitem>
- <para>
- paranthesises () may be used to enclose multi-byte characters -
- eg. diacritics or special national combinations (eg. Spanish
- "ll"). When found in the input stream (or a search term),
- these characters are viewed and sorted as a single character, with a
- sorting value depending on the position of the group in the value
- statement.
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>uppercase <emphasis>value-set</emphasis></term>
- <listitem>
- <para>
- This directive introduces the
- upper-case equivalencis to the value set (if any). The number and
- order of the entries in the list should be the same as in the
- <literal>lowercase</literal> directive.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>space <emphasis>value-set</emphasis></term>
- <listitem>
- <para>
- This directive introduces the character
- which separate words in the input stream. Depending on the
- completeness mode of the field in question, these characters either
- terminate an index entry, or delimit individual "words" in
- the input stream. The order of the elements is not significant —
- otherwise the representation is the same as for the
- <literal>uppercase</literal> and <literal>lowercase</literal>
- directives.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>map <emphasis>value-set</emphasis>
- <emphasis>target</emphasis></term>
- <listitem>
- <para>
- This directive introduces a
- mapping between each of the members of the value-set on the left to
- the character on the right. The character on the right must occur in
- the value set (the <literal>lowercase</literal> directive) of
- the character set, but
- it may be a paranthesis-enclosed multi-octet character. This directive
- may be used to map diacritics to their base characters, or to map
- HTML-style character-representations to their natural form, etc.
- </para>
- </listitem></varlistentry>
- </variablelist>
+ Section "Virtual Hosts" in the YAZ manual.
+ <filename>http://www.indexdata.dk/yaz/doc/server.vhosts.tkl</filename>
</para>
-
- </sect2>
-
</sect1>
- <sect1 id="formats">
- <title>Exchange Formats</title>
-
- <para>
- Converting records from the internal structure to en exchange format
- is largely an automatic process. Currently, the following exchange
- formats are supported:
- </para>
-
- <para>
- <itemizedlist>
- <listitem>
- <para>
- GRS-1. The internal representation is based on GRS-1, so the
- conversion here is straightforward. The system will create
- applied variant and supported variant lists as required, if a record
- contains variant information.
- </para>
- </listitem>
-
- <listitem>
- <para>
- SUTRS. Again, the mapping is fairly straighforward. Indentation
- is used to show the hierarchical structure of the record. All
- "GRS" type records support both the GRS-1 and SUTRS
- representations.
- </para>
- </listitem>
-
- <listitem>
- <para>
- ISO2709-based formats (USMARC, etc.). Only records with a
- two-level structure (corresponding to fields and subfields) can be
- directly mapped to ISO2709. For records with a different structuring
- (eg., GILS), the representation in a structure like USMARC involves a
- schema-mapping (see section <xref linkend="schema-mapping"/>), to an
- "implied" USMARC schema (implied,
- because there is no formal schema which specifies the use of the
- USMARC fields outside of ISO2709). The resultant, two-level record is
- then mapped directly from the internal representation to ISO2709. See
- the GILS schema definition files for a detailed example of this
- approach.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Explain. This representation is only available for records
- belonging to the Explain schema.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Summary. This ASN-1 based structure is only available for records
- belonging to the Summary schema - or schema which provide a mapping
- to this schema (see the description of the schema mapping facility
- above).
- </para>
- </listitem>
-
- <listitem>
- <para>
- SOIF. Support for this syntax is experimental, and is currently
- keyed to a private Index Data OID (1.2.840.10003.5.1000.81.2). All
- abstract syntaxes can be mapped to the SOIF format, although nested
- elements are represented by concatenation of the tag names at each
- level.
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
-
- </sect1>
+
</chapter>
+
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