-<chapter id="querymodel">
- <!-- $Id: querymodel.xml,v 1.2 2006-06-13 13:45:08 marc Exp $ -->
- <title>Query Model</title>
-
+ <chapter id="querymodel">
+ <!-- $Id: querymodel.xml,v 1.3 2006-06-14 12:20:06 marc Exp $ -->
+ <title>Query Model</title>
+
<sect1 id="querymodel-overview">
<title>Query Model Overview</title>
-
+
<para>
Zebra is born as a networking Information Retrieval engine adhering
to the international standards
<literal>PQN</literal>, and is thoroughly explained in
<xref linkend="querymodel-pqf"/>.
</para>
-
+
<para>
In addition, Zebra can be configured to understand and map the
<literal>Common Query Language</literal>
representation in
<xref linkend="querymodel-cql-to-pqf"/>.
</para>
- </sect1>
-
+ </sect1>
+
<sect1 id="querymodel-pqf">
<title>Prefix Query Format structure and syntax</title>
<para>
- The
- <ulink url="&url.yaz.pqf;">PQF
- grammer</ulink> is documented in the YAZ manual, and shall not be
- repeated here.
- This textual PQF representation
+ The <ulink url="&url.yaz.pqf;">PQF grammer</ulink>
+ is documented in the YAZ manual, and shall not be
+ repeated here. This textual PQF representation
is always during search mapped to the equivalent Zebra internal
query parse tree.
</para>
-
+
<sect2 id="querymodel-pqf-tree">
<title>PQF tree structure</title>
- <para>
- The PQF parse tree - or the equivalent textual representation -
- may start with one specification of the
- <emphasis>attribute set</emphasis> used. Following is a query
- tree, which
- consists of <emphasis>atomic query parts</emphasis>, eventually
- paired by <emphasis>boolean binary operators</emphasis>, and
- finally <emphasis>recursively combined </emphasis> into
- complex query trees.
- </para>
-
- <sect3 id="querymodel-attribute-sets">
- <title>Attribute sets</title>
<para>
+ The PQF parse tree - or the equivalent textual representation -
+ may start with one specification of the
+ <emphasis>attribute set</emphasis> used. Following is a query
+ tree, which
+ consists of <emphasis>atomic query parts</emphasis>, eventually
+ paired by <emphasis>boolean binary operators</emphasis>, and
+ finally <emphasis>recursively combined </emphasis> into
+ complex query trees.
+ </para>
+
+ <sect3 id="querymodel-attribute-sets">
+ <title>Attribute sets</title>
+ <para>
Attribute sets define the exact meaning and semantics of queries
issued. Zebra comes with some predefined attribute set
definitions, others can easily be defined and added to the
configuration.
<note>
- The Zebra internal query procesing is modeled after
- the <literal>Bib1</literal> attribute set, and the non-use
- attributes type 2-9 are hard-wired in. It is therefore essential
- to be familiar with <xref linkend="querymodel-bib1"/>.
- </note>
- </para>
-
- <table id="querymodel-attribute-sets-table">
- <caption>Attribute sets predefined in Zebra</caption>
- <!--
- <thead>
- <tr><td>one</td><td>two</td></tr>
- </thead>
- -->
- <tbody>
- <tr>
- <td><emphasis>exp-1</emphasis></td>
- <td><literal>Explain</literal> attribute set</td>
- <td>Special attribute set used on the special automagic
- <literal>IR-Explain-1</literal> database to gain information on
- server capabilities, database names, and database
- and semantics.</td>
- </tr>
- <tr>
- <td><emphasis>bib-1</emphasis></td>
- <td><literal>Bib1</literal> attribute set</td>
- <td>Standard PQF query language attribute set which defines the
- semantics of Z39.50 searching. In addition, all of the
- non-use attributes (type 2-9) define the Zebra internal query
- processing</td>
- </tr>
- <tr>
- <td><emphasis>gils</emphasis></td>
- <td><literal>GILS</literal> attribute set</td>
- <td>Extention to the <literal>Bib1</literal> attribute set.</td>
- </tr>
- </tbody>
- </table>
- </sect3>
-
- <sect3 id="querymodel-boolean-operators">
- <title>Boolean operators</title>
- <para>
+ The Zebra internal query procesing is modeled after
+ the <literal>Bib1</literal> attribute set, and the non-use
+ attributes type 2-9 are hard-wired in. It is therefore essential
+ to be familiar with <xref linkend="querymodel-bib1"/>.
+ </note>
+ </para>
+
+ <table id="querymodel-attribute-sets-table">
+ <caption>Attribute sets predefined in Zebra</caption>
+ <!--
+ <thead>
+ <tr><td>one</td><td>two</td></tr>
+ </thead>
+ -->
+ <tbody>
+ <tr>
+ <td><emphasis>exp-1</emphasis></td>
+ <td><literal>Explain</literal> attribute set</td>
+ <td>Special attribute set used on the special automagic
+ <literal>IR-Explain-1</literal> database to gain information on
+ server capabilities, database names, and database
+ and semantics.</td>
+ </tr>
+ <tr>
+ <td><emphasis>bib-1</emphasis></td>
+ <td><literal>Bib1</literal> attribute set</td>
+ <td>Standard PQF query language attribute set which defines the
+ semantics of Z39.50 searching. In addition, all of the
+ non-use attributes (type 2-9) define the Zebra internal query
+ processing</td>
+ </tr>
+ <tr>
+ <td><emphasis>gils</emphasis></td>
+ <td><literal>GILS</literal> attribute set</td>
+ <td>Extention to the <literal>Bib1</literal> attribute set.</td>
+ </tr>
+ </tbody>
+ </table>
+ </sect3>
+
+ <sect3 id="querymodel-boolean-operators">
+ <title>Boolean operators</title>
+ <para>
A pair of subquery trees, or of atomic queries, is combined
using the standard boolean operators into new query trees.
- </para>
-
- <table id="querymodel-boolean-operators-table">
- <caption>Boolean operators</caption>
- <!--
- <thead>
- <tr><td>one</td><td>two</td></tr>
- </thead>
- -->
- <tbody>
- <tr><td><emphasis>@and</emphasis></td>
- <td>binary <literal>AND</literal> operator</td>
- <td>Set intersection of two atomic queries hit sets</td>
- </tr>
- <tr><td><emphasis>@or</emphasis></td>
- <td>binary <literal>OR</literal> operator</td>
- <td>Set union of two atomic queries hit sets</td>
- </tr>
- <tr><td><emphasis>@not</emphasis></td>
- <td>binary <literal>AND NOT</literal> operator</td>
- <td>Set complement of two atomic queries hit sets</td>
- </tr>
- <tr><td><emphasis>@prox</emphasis></td>
- <td>binary <literal>PROXIMY</literal> operator</td>
- <td>Set intersection of two atomic queries hit sets. In
- addition, the intersection set is purged for all
- documents which do not satisfy the requested query
- term proximity. Usually a proper subset of the AND
- operation.</td>
- </tr>
- </tbody>
- </table>
-
- <para>
+ </para>
+
+ <table id="querymodel-boolean-operators-table">
+ <caption>Boolean operators</caption>
+ <!--
+ <thead>
+ <tr><td>one</td><td>two</td></tr>
+ </thead>
+ -->
+ <tbody>
+ <tr><td><emphasis>@and</emphasis></td>
+ <td>binary <literal>AND</literal> operator</td>
+ <td>Set intersection of two atomic queries hit sets</td>
+ </tr>
+ <tr><td><emphasis>@or</emphasis></td>
+ <td>binary <literal>OR</literal> operator</td>
+ <td>Set union of two atomic queries hit sets</td>
+ </tr>
+ <tr><td><emphasis>@not</emphasis></td>
+ <td>binary <literal>AND NOT</literal> operator</td>
+ <td>Set complement of two atomic queries hit sets</td>
+ </tr>
+ <tr><td><emphasis>@prox</emphasis></td>
+ <td>binary <literal>PROXIMY</literal> operator</td>
+ <td>Set intersection of two atomic queries hit sets. In
+ addition, the intersection set is purged for all
+ documents which do not satisfy the requested query
+ term proximity. Usually a proper subset of the AND
+ operation.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <para>
For example, we can combine the terms
<emphasis>information</emphasis> and <emphasis>retrieval</emphasis>
into different searches in the default index of the default
Querying for the union of all documents containing the
terms <emphasis>information</emphasis> OR
<emphasis>retrieval</emphasis>:
- <screen>
- @or information retrieval
- </screen>
- </para>
- <para>
+ <screen>
+ Z> find @or information retrieval
+ </screen>
+ </para>
+ <para>
Querying for the intersection of all documents containing the
terms <emphasis>information</emphasis> AND
<emphasis>retrieval</emphasis>:
The hit set is a subset of the coresponding
OR query.
- <screen>
- @and information retrieval
- </screen>
- </para>
- <para>
+ <screen>
+ Z> find @and information retrieval
+ </screen>
+ </para>
+ <para>
Querying for the intersection of all documents containing the
terms <emphasis>information</emphasis> AND
<emphasis>retrieval</emphasis>, taking proximity into account:
The hit set is a subset of the coresponding
AND query.
- <screen>
- @prox information retrieval
- </screen>
- </para>
- <para>
+ <screen>
+ Z> find @prox information retrieval
+ </screen>
+ </para>
+ <para>
Querying for the intersection of all documents containing the
terms <emphasis>information</emphasis> AND
<emphasis>retrieval</emphasis>, in the same order and near each
other as described in the term list
The hit set is a subset of the coresponding
PROXIMY query.
- <screen>
- "information retrieval"
- </screen>
- </para>
- </sect3>
-
-
- <sect3 id="querymodel-atomic-queries">
- <title>Atomic queries</title>
- <para>
+ <screen>
+ Z> find "information retrieval"
+ </screen>
+ </para>
+ </sect3>
+
+
+ <sect3 id="querymodel-atomic-queries">
+ <title>Atomic queries</title>
+ <para>
Atomic queries are the query parts which work on one acess point
only. These consist of <literal>an attribute list</literal>
followed by a <literal>single term</literal> or a
<literal>quoted term list</literal>.
- </para>
- <para>
+ </para>
+ <para>
Unsupplied non-use attributes type 2-9 are either inherited from
higher nodes in the query tree, or are set to Zebra's default values.
See <xref linkend="querymodel-bib1"/> for details.
- </para>
-
- <table id="querymodel-atomic-queries-table">
- <caption>Atomic queries</caption>
- <!--
- <thead>
- <tr><td>one</td><td>two</td></tr>
- </thead>
- -->
- <tbody>
- <tr><td><emphasis>attribute list</emphasis></td>
- <td>List of <literal>orthogonal</literal> attributes</td>
- <td>Any of the orthogonal attribute types may be omitted,
+ </para>
+
+ <table id="querymodel-atomic-queries-table">
+ <caption>Atomic queries</caption>
+ <!--
+ <thead>
+ <tr><td>one</td><td>two</td></tr>
+ </thead>
+ -->
+ <tbody>
+ <tr><td><emphasis>attribute list</emphasis></td>
+ <td>List of <literal>orthogonal</literal> attributes</td>
+ <td>Any of the orthogonal attribute types may be omitted,
these are inherited from higher query tree nodes, or if not
inherited, are set to the default Zebra configuration values.
- </td>
- </tr>
- <tr><td><emphasis>term</emphasis></td>
- <td>single <literal>term</literal>
- or <literal>quoted term list</literal> </td>
- <td>Here the search terms or list of search terms is added
+ </td>
+ </tr>
+ <tr><td><emphasis>term</emphasis></td>
+ <td>single <literal>term</literal>
+ or <literal>quoted term list</literal> </td>
+ <td>Here the search terms or list of search terms is added
to the query</td>
- </tr>
- </tbody>
- </table>
- <para>
+ </tr>
+ </tbody>
+ </table>
+ <para>
Querying for the term <emphasis>information</emphasis> in the
default index using the default attribite set, the server choice
of access point/index, and the default non-use attributes.
- <screen>
- "information"
- </screen>
- </para>
- <para>
- Equivalent query fully specified:
<screen>
- @attrset bib-1 @attr 1=1017 @attr 2=3 @attr 3=3 @attr 4=1 @attr 5=100 @attr 6=1 "information"
+ Z> find "information"
</screen>
- </para>
-
- <para>
- Finding all documents which have empty titles. Notice that the
- empty term must be quoted, but is otherwise legal.
+ </para>
+ <para>
+ Equivalent query fully specified:
<screen>
- @attr 1=4 ""
+ Z> find @attrset bib-1 @attr 1=1017 @attr 2=3 @attr 3=3 @attr 4=1 @attr 5=100 @attr 6=1 "information"
</screen>
- </para>
-
- </sect3>
+ </para>
+
+ <para>
+ Finding all documents which have empty titles. Notice that the
+ empty term must be quoted, but is otherwise legal.
+ <screen>
+ Z> find @attr 1=4 ""
+ </screen>
+ </para>
+ </sect3>
+
<sect3 id="querymodel-use-string">
- <title>Zebra's special use attribute of type 'string'</title>
+ <title>Zebra's special use attribute type 1 of form 'string'</title>
<para>
The numeric <literal>use (type 1)</literal> attribute is usually
- refered to from a given
+ refered to from a given
attribute set. In addition, Zebra let you use
<emphasis>any internal index
- name defined in your configuration</emphasis>
- as use atribute value. This is a great feature for
+ name defined in your configuration</emphasis>
+ as use atribute value. This is a great feature for
debugging, and when you do
not need the complecity of defined use attribute values. It is
the preferred way of accessing Zebra indexes directly.
Finding all documents which have the term list "information
retrieval" in an Zebra index, using it's internal full string name.
<screen>
- @attr 1=sometext "information retrieval"
+ Z> find @attr 1=sometext "information retrieval"
</screen>
- </para>
+ </para>
<para>
Searching the bib-1 use attribute 54 using it's string name:
<screen>
- @attr 1=Code-language eng
+ Z> find @attr 1=Code-language eng
</screen>
- </para>
+ </para>
<para>
Searching in any silly string index - if it's defined in your
indexation rules and can be parsed by the PQF parser.
this facility, as it might confuse your users with some very
unexpected results.
<screen>
- @attr 1=silly/xpath/alike[@index]/name "information retrieval"
+ Z> find @attr 1=silly/xpath/alike[@index]/name "information retrieval"
</screen>
- </para>
- <para>
+ </para>
+ <para>
See <xref linkend="querymodel-bib1-mapping"/> for details, and
- <xref linkend="server-sru"/>
+ <xref linkend="server-sru"/>
for the SRU PQF query extention using string names as a fast
- debugging facility.
- </para>
- </sect3>
-
- </sect2>
-
- <sect2 id="querymodel-exp1">
- <title>Explain Attribute Set</title>
+ debugging facility.
+ </para>
+ </sect3>
+
+ <sect3 id="querymodel-use-xpath">
+ <title>Zebra's special use attribute type 1 of form 'XPath'
+ for GRS filters</title>
+ <para>
+ As we have seen above, it is possible (albeit seldom a great
+ idea) to emulate
+ <ulink url="http://www.w3.org/TR/xpath">XPath 1.0</ulink> based
+ search by defining <literal>use (type 1)</literal>
+ <emphasis>string</emphasis> attributes which in appearence
+ <emphasis>resemble XPath queries</emphasis>. There are two
+ problems with this approach: first, the XPath-look-alike has to
+ be defined at indexation time, no new undefined
+ XPath queries can entered at search time, and second, it might
+ confuse users very much that an XPath-alike index name in fact
+ gets populated from a possible entirely different XML element
+ than it pretends to acess.
+ </para>
+ <para>
+ When using the <literal>GRS Record Model</literal>
+ (see <xref linkend="record-model-grs"/>), we have the
+ possibility to embed <emphasis>life</emphasis>
+ XPath expressions
+ in the PQF queries, which are here called
+ <literal>use (type 1)</literal> <emphasis>xpath</emphasis>
+ attributes. You must enable the
+ <literal>xpath enable</literal> directive in your
+ <literal>.abs</literal> config files.
+ </para>
+ <note>
+ Only a <emphasis>very</emphasis> restricted subset of the
+ <ulink url="http://www.w3.org/TR/xpath">XPath 1.0</ulink>
+ standard is supported as the GRS record model is simpler than
+ a full XML DOM structure. See the following examples for
+ possibilities.
+ </note>
+ <para>
+ Finding all documents which have the term "content"
+ inside a text node found in a specific XML DOM
+ <emphasis>subtree</emphasis>, whose starting element is
+ adressed by XPath.
+ <screen>
+ Z> find @attr 1=/root content
+ Z> find @attr 1=/root/first content
+ </screen>
+ <emphasis>Notice that the
+ XPath must be absolute, i.e., must start with '/', and that the
+ XPath <literal>decendant-or-self</literal> axis followed by a
+ text node selection <literal>text()</literal> is implicitly
+ appended to the stated XPath.
+ </emphasis>
+ It follows that the above searches are interpreted as:
+ <screen>
+ Z> find @attr 1=/root//text() content
+ Z> find @attr 1=/root/first//text() content
+ </screen>
+ </para>
+
+ <para>
+ Filter the adressing XPath by a predicate working on exact
+ string values in
+ attributes (in the XML sense) can be done: return all those docs which
+ have the term "english" contained in one of all text subnodes of
+ the subtree defined by the XPath
+ <literal>/record/title[@lang='en']</literal>
+ <screen>
+ Z> find @attr 1=/record/title[@lang='en'] english
+ </screen>
+ </para>
+
+ <para>
+ Combining numeric indexes, boolean expressions,
+ and xpath based searches is possible:
+ <screen>
+ Z> find @attr 1=/record/title @and foo bar
+ Z> find @and @attr 1=/record/title foo @attr 1=4 bar
+ </screen>
+ </para>
+ <para>
+ Escaping PQF keywords and other non-parseable XPath constructs
+ with <literal>'{ }'</literal> to prevent syntax errors:
+ <screen>
+ Z> find @attr {1=/root/first[@attr='danish']} content
+ Z> find @attr {1=/root/second[@attr='danish lake']}
+ Z> find @attr {1=/root/third[@attr='dansk s\xc3\xb8']}
+ </screen>
+ </para>
+ <warning>
+ It is worth mentioning that these dynamic performed XPath
+ queries are a performance bottelneck, as no optimized
+ specialized indexes can be used. Therefore, avoid the use of
+ this facility when speed is essential, and the database content
+ size is medium to large.
+ </warning>
+ </sect3>
+
+ </sect2>
+
+ <sect2 id="querymodel-exp1">
+ <title>Explain Attribute Set</title>
<para>
The Z39.50 standard defines the
<ulink url="&url.z39.50.explain;">Explain</ulink>attribute set
<para>
The attribute-set <literal>exp-1</literal> consists of a single
<literal>Use (type 1)</literal> attribute.
- </para>
- <para>
+ </para>
+ <para>
In addition, the non-Use
<literal>bib-1</literal> attributes, that is, the types
<literal>Relation</literal>, <literal>Position</literal>,
and <literal>Completeness</literal> are imported from
the <literal>bib-1</literal> attribute set, and may be used
within any explain query.
- </para>
+ </para>
- <sect3 id="querymodel-exp1-use">
+ <sect3 id="querymodel-exp1-use">
<title>Use Attributes (type = 1)</title>
- <para>
- The following Explain search atributes are supported:
- <literal>ExplainCategory</literal> (@attr 1=1),
- <literal>DatabaseName</literal> (@attr 1=3),
- <literal>DateAdded</literal> (@attr 1=9),
- <literal>DateChanged</literal>(@attr 1=10).
- </para>
- <para>
- A search in the use attribute <literal>ExplainCategory</literal>
- supports only these predefined values:
- <literal>CategoryList</literal>, <literal>TargetInfo</literal>,
- <literal>DatabaseInfo</literal>, <literal>AttributeDetails</literal>.
- </para>
+ <para>
+ The following Explain search atributes are supported:
+ <literal>ExplainCategory</literal> (@attr 1=1),
+ <literal>DatabaseName</literal> (@attr 1=3),
+ <literal>DateAdded</literal> (@attr 1=9),
+ <literal>DateChanged</literal>(@attr 1=10).
+ </para>
+ <para>
+ A search in the use attribute <literal>ExplainCategory</literal>
+ supports only these predefined values:
+ <literal>CategoryList</literal>, <literal>TargetInfo</literal>,
+ <literal>DatabaseInfo</literal>, <literal>AttributeDetails</literal>.
+ </para>
<para>
See <filename>tab/explain.att</filename> and the
+ <ulink url="&url.z39.50;">Z39.50</ulink> standard
for more information.
- </para>
- </sect3>
+ </para>
+ </sect3>
<sect3>
<title>Explain searches with yaz-client</title>
- <para>
- Classic Explain only defines retrieval of Explain information
- via ASN.1. Pratically no Z39.50 clients supports this. Fortunately
- they don't have to - Zebra allows retrieval of this information
- in other formats:
- <literal>SUTRS</literal>, <literal>XML</literal>,
- <literal>GRS-1</literal> and <literal>ASN.1</literal> Explain.
- </para>
-
+ <para>
+ Classic Explain only defines retrieval of Explain information
+ via ASN.1. Pratically no Z39.50 clients supports this. Fortunately
+ they don't have to - Zebra allows retrieval of this information
+ in other formats:
+ <literal>SUTRS</literal>, <literal>XML</literal>,
+ <literal>GRS-1</literal> and <literal>ASN.1</literal> Explain.
+ </para>
+
<para>
List supported categories to find out which explain commands are
supported:
<screen>
Z> base IR-Explain-1
- Z> @attr exp1 1=1 categorylist
+ Z> find @attr exp1 1=1 categorylist
Z> form sutrs
Z> show 1+2
</screen>
</para>
-
+
<para>
Get target info, that is, investigate which databases exist at
this server endpoint:
<screen>
Z> base IR-Explain-1
- Z> @attr exp1 1=1 targetinfo
+ Z> find @attr exp1 1=1 targetinfo
Z> form xml
Z> show 1+1
Z> form grs-1
Z> show 1+1
</screen>
</para>
-
+
<para>
List all supported databases, the number of hits
is the number of databases found, which most commonly are the
<literal>IR-Explain-1</literal> databases.
<screen>
Z> base IR-Explain-1
- Z> f @attr exp1 1=1 databaseinfo
+ Z> find @attr exp1 1=1 databaseinfo
Z> form sutrs
Z> show 1+2
</screen>
Get database info record for database <literal>Default</literal>.
<screen>
Z> base IR-Explain-1
- Z> @and @attr exp1 1=1 databaseinfo @attr exp1 1=3 Default
+ Z> find @and @attr exp1 1=1 databaseinfo @attr exp1 1=3 Default
</screen>
Identical query with explicitly specified attribute set:
<screen>
Z> base IR-Explain-1
- Z> @attrset exp1 @and @attr 1=1 databaseinfo @attr 1=3 Default
+ Z> find @attrset exp1 @and @attr 1=1 databaseinfo @attr 1=3 Default
</screen>
</para>
-
+
<para>
Get attribute details record for database
<literal>Default</literal>.
found.
<screen>
Z> base IR-Explain-1
- Z> @and @attr exp1 1=1 attributedetails @attr exp1 1=3 Default
+ Z> find @and @attr exp1 1=1 attributedetails @attr exp1 1=3 Default
</screen>
Identical query with explicitly specified attribute set:
<screen>
Z> base IR-Explain-1
- Z> @attrset exp1 @and @attr 1=1 attributedetails @attr 1=3 Default
+ Z> find @attrset exp1 @and @attr 1=1 attributedetails @attr 1=3 Default
</screen>
</para>
</sect3>
-
- </sect2>
-
- <sect2 id="querymodel-bib1">
- <title>Bib1 Attribute Set</title>
- <para>
- Something about querying to be written ..
- </para>
- <para>
- Most of the information contained in this section is an excerpt of
- the <literal>ATTRIBUTE SET BIB-1 (Z39.50-1995)
- SEMANTICS</literal>, found at <ulink
- url="&url.z39.50.attset.bib1.1995;">The BIB-1
- Attribute Set Semantics</ulink> from 1995, also in an updated
- <ulink url="&url.z39.50.attset.bib1;">Bib-1
- Attribute Set</ulink>
- version from 2003. Index Data is not the copyright holder of this
- information.
- </para>
+
+ </sect2>
+
+ <sect2 id="querymodel-bib1">
+ <title>Bib1 Attribute Set</title>
+ <para>
+ Something about querying to be written ..
+ </para>
+ <para>
+ Most of the information contained in this section is an excerpt of
+ the <literal>ATTRIBUTE SET BIB-1 (Z39.50-1995)
+ SEMANTICS</literal>,
+ found at <ulink url="&url.z39.50.attset.bib1.1995;">. The BIB-1
+ Attribute Set Semantics</ulink> from 1995, also in an updated
+ <ulink url="&url.z39.50.attset.bib1;">Bib-1
+ Attribute Set</ulink>
+ version from 2003. Index Data is not the copyright holder of this
+ information.
+ </para>
<sect3 id="querymodel-bib1-use">
- <title>Use Attributes (type = 1)</title>
- </sect3>
-
- <sect3 id="querymodel-bib1-relation">
- <title>Relation Attributes (type = 2)</title>
- </sect3>
- <para>
- </para>
-
- <sect3 id="querymodel-bib1-position">
- <title>Position Attributes (type = 3)</title>
- </sect3>
-
- <sect3 id="querymodel-bib1-structure">
- <title>Structure Attributes (type = 4)</title>
- </sect3>
-
- <sect3 id="querymodel-bib1-truncation">
- <title>Truncation Attributes (type = 5)</title>
- </sect3>
-
- <sect3 id="querymodel-bib1-completeness">
- <title>Completeness Attributes (type = 6)</title>
- </sect3>
-
- <sect3 id="querymodel-bib1-sorting">
- <title>Zebra Extention Sorting Attributes (type = 7)</title>
- </sect3>
-
- <sect3 id="querymodel-bib1-estimation">
- <title>Zebra Extention Search Estimation Attributes (type = 8)</title>
- </sect3>
-
- <sect3 id="querymodel-bib1-weight">
- <title>Zebra Extention Weight Attributes (type = 9)</title>
- </sect3>
-
- </sect2>
-
- <sect2 id="querymodel-bib1-mapping">
- <title>Mapping from Bib1 Attributes to Zebra internal
- register indexes</title>
- <para>
- </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.
- <!-- ### whatever the hell _that_ is -->
- </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>
+ <title>Use Attributes (type = 1)</title>
+ </sect3>
- <para>
- For the <emphasis>Truncation</emphasis> attribute,
- <emphasis>No Truncation</emphasis> is the default.
- <emphasis>Left Truncation</emphasis> is not supported.
- <emphasis>Process # in search term</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>
- </sect2>
+ <para>
+ Phrase search for <emphasis>information retrieval</emphasis> in
+ the title-register:
+ <screen>
+ Z> find @attr 1=4 "information retrieval"
+ </screen>
+ </para>
- <sect2 id="querymodel-regular">
- <title>Regular expressions</title>
+ <sect3 id="querymodel-bib1-relation">
+ <title>Relation Attributes (type = 2)</title>
+ </sect3>
<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> zero or once. 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.
+ Ranked search for <emphasis>information retrieval</emphasis> in
+ the title-register
+ (see <xref linkend="administration-ranking"/> for the glory details):
+ <screen>
+ Z> find @attr 1=4 @attr 2=102 "information retrieval"
+ </screen>
</para>
+
+ <sect3 id="querymodel-bib1-position">
+ <title>Position Attributes (type = 3)</title>
+ </sect3>
+
+ <sect3 id="querymodel-bib1-structure">
+ <title>Structure Attributes (type = 4)</title>
+ </sect3>
+
<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.
+ For example, 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>
+ Z> find @attr 4=109 @attr 2=5 @attr gils 1=2038 -114
+ </screen>
</para>
+ <sect3 id="querymodel-bib1-truncation">
+ <title>Truncation Attributes (type = 5)</title>
+ </sect3>
+
+ <sect3 id="querymodel-bib1-completeness">
+ <title>Completeness Attributes (type = 6)</title>
+ </sect3>
</sect2>
+
- <sect2 id="querymodel-examples">
- <title>Query examples</title>
+ <sect2 id="querymodel-zebra-attr-search">
+ <title>Zebra specific Search Extentions to all Attribute Sets</title>
+ <para>
+ Zebra extends the Bib1 attribute types, and these extentions are
+ recognized regardless of attribute
+ set used in a <literal>search</literal> operation query.
+ </para>
+ <table id="querymodel-zebra-attr-search-table">
+ <caption>Zebra Search Attribute Extentions</caption>
+ <thead>
+ <tr>
+ <td><emphasis>Name and Type</emphasis></td>
+ <td>Operation</td>
+ <td>Zebra version</td>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <td><emphasis>Embedded Sort (type 7)</emphasis></td>
+ <td>search</td>
+ <td>1.1</td>
+ </tr>
+ <tr>
+ <td><emphasis>Term Set (type 8)</emphasis></td>
+ <td>search</td>
+ <td>1.1</td>
+ </tr>
+ <tr>
+ <td><emphasis>Rank weight (type 9)</emphasis></td>
+ <td>search</td>
+ <td>1.1</td>
+ </tr>
+ <tr>
+ <td><emphasis>Approx Limit (type 9)</emphasis></td>
+ <td>search</td>
+ <td>1.4</td>
+ </tr>
+ <tr>
+ <td><emphasis>Term Reference (type 10)</emphasis></td>
+ <td>search</td>
+ <td>1.4</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <sect3 id="querymodel-zebra-attr-sorting">
+ <title>Zebra Extention Embedded Sort Attribute (type 7)</title>
+ </sect3>
<para>
- Phrase search for <emphasis>information retrieval</emphasis> in
- the title-register:
+ The embedded sort is a way to specify sort within a query - thus
+ removing the need to send a Sort Request separately. It is both
+ faster and does not require clients to deal with the Sort
+ Facility.
+ </para>
+ <para>
+ The possible values after attribute <literal>type 7</literal> are
+ <literal>1</literal> ascending and
+ <literal>2</literal> descending.
+ The attributes+term (APT) node is separate from the
+ rest and must be <literal>@or</literal>'ed.
+ The term associated with APT is the sorting level in integers,
+ where <literal>0</literal> means primary sort,
+ <literal>1</literal> means secondary sort, and so forth.
+ See also <xref linkend="administration-ranking"/>.
+ </para>
+ <para>
+ For example, searching for water, sort by title (ascending)
<screen>
- @attr 1=4 "information retrieval"
+ Z> find @or @attr 1=1016 water @attr 7=1 @attr 1=4 0
</screen>
</para>
-
<para>
- Ranked search for the same thing:
+ Or, searching for water, sort by title ascending, then date descending
<screen>
- @attr 1=4 @attr 2=102 "Information retrieval"
+ Z> find @or @or @attr 1=1016 water @attr 7=1 @attr 1=4 0 @attr 7=2 @attr 1=30 1
+ </screen>
+ </para>
+
+ <sect3 id="querymodel-zebra-attr-estimation">
+ <title>Zebra Extention Term Set Attribute (type 8)</title>
+ </sect3>
+ <para>
+ The Term Set feature is a facility that allows a search to store
+ hitting terms in a "pseudo" resultset; thus a search (as usual) +
+ a scan-like facility. Requires a client that can do named result
+ sets since the search generates two result sets. The value for
+ attribute 8 is the name of a result set (string). The terms in
+ the named term set are returned as SUTRS records.
+ </para>
+ <para>
+ For example, searching for u in title, right truncated, and
+ storing the result in term set named 'aset'
+ <screen>
+ Z> find @attr 5=1 @attr 1=4 @attr 8=aset u
+ </screen>
+ </para>
+ <warning>
+ The model has one serious flaw: we don't know the size of term
+ set. Experimental. Do not use in production code.
+ </warning>
+
+ <sect3 id="querymodel-zebra-attr-weight">
+ <title>Zebra Extention Rank Weight Attribute (type 9)</title>
+ </sect3>
+ <para>
+ Rank weight is a way to pass a value to a ranking algorithm - so
+ that one APT has one value - while another as a different one.
+ See also <xref linkend="administration-ranking"/>.
+ </para>
+ <para>
+ For example, searching for utah in title with weight 30 as well
+ as any with weight 20:
+ <screen>
+ Z> find @attr 2=102 @or @attr 9=30 @attr 1=4 utah @attr 9=20 utah
</screen>
</para>
+ <sect3 id="querymodel-zebra-attr-limit">
+ <title>Zebra Extention Approximative Limit Attribute (type 9)</title>
+ </sect3>
+ <para>
+ Newer Zebra versions normally estemiates hit count for every APT
+ (leaf) in the query tree. These hit counts are returned as part of
+ the searchResult-1 facility in the binary encoded Z39.50 search
+ response packages.
+ </para>
+ <para>
+ By setting a limit for the APT we can make Zebra turn into
+ approximate hit count when a certain hit count limit is
+ reached. A value of zero means exact hit count.
+ </para>
+ <para>
+ For example, we might be intersted in exact hit count for a, but
+ for b we allow hit count estimates for 1000 and higher.
+ <screen>
+ Z> find @and a @attr 9=1000 b
+ </screen>
+ </para>
+ <note>
+ The estimated hit count fascility makes searches faster, as one
+ only needs to process large hit lists partially.
+ </note>
+ <warning>
+ This facility clashes with rank weight, because there all
+ documents in the hit lists need to be examined for scoring and
+ re-sorting.
+ It is an experimental
+ extention. Do not use in production code.
+ </warning>
+
+ <sect3 id="querymodel-zebra-attr-termref">
+ <title>Zebra Extention Term Reference Attribute (type 10)</title>
+ </sect3>
+ <para>
+ Zebra supports the searchResult-1 facility. If attribute 10 is
+ given, that specifies a subqueryId value returned as part of the
+ search result. It is a way for a client to name an APT part of a
+ query.
+ </para>
+ <!--
<para>
- Phrase search with a regular expression:
<screen>
- @attr 1=4 @attr 5=102 "informat.* retrieval"
</screen>
</para>
+ -->
+ <warning>
+ Experimental. Do not use in production code.
+ </warning>
+
+ </sect2>
+
+
+ <sect2 id="querymodel-zebra-attr-scan">
+ <title>Zebra specific Scan Extentions to all Attribute Sets</title>
+ <para>
+ Zebra extends the Bib1 attribute types, and these extentions are
+ recognized regardless of attribute
+ set used in a <literal>scan</literal> operation query.
+ </para>
+ <table id="querymodel-zebra-attr-scan-table">
+ <caption>Zebra Scan Attribute Extentions</caption>
+ <thead>
+ <tr>
+ <td><emphasis>Name and Type</emphasis></td>
+ <td>Operation</td>
+ <td>Zebra version</td>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <td><emphasis>Result Set Narrow (type 8)</emphasis></td>
+ <td>scan</td>
+ <td>1.3</td>
+ </tr>
+ <tr>
+ <td><emphasis>Approximative Limit (type 9)</emphasis></td>
+ <td>scan</td>
+ <td>1.4</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <sect3 id="querymodel-zebra-attr-xyz">
+ <title>Zebra Extention Result Set Narrow (type 8)</title>
+ </sect3>
+ <para>
+ If attribute 8 is given for scan, the value is the name of a
+ result set. Each hit count in scan is @and'ed with the result set
+ given.
+ </para>
+ <!--
<para>
- Ranked search with a regular expression:
<screen>
- @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval"
</screen>
</para>
+ -->
+ <warning>
+ Experimental and buggy. Definitely not to be used in production code.
+ </warning>
+ <sect3 id="querymodel-zebra-attr-xyz">
+ <title>Zebra Extention Approximative Limit (type 9)</title>
+ </sect3>
+ <para>
+ The approximative limit (as for search) is a way to enable approx
+ hit counts for scan hit counts.
+ </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>
+ </screen>
</para>
+ -->
+ <warning>
+ Experimental. Do not use in production code.
+ </warning>
+
+
</sect2>
+
+
+ <sect2 id="querymodel-bib1-mapping">
+ <title>Mapping from Bib1 Attributes to Zebra internal
+ register indexes</title>
+ <para>
+ TO-DO
+ </para>
<!-- see in util/zebramap.c
return 0;
-->
+
+
+ <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.
+ <!-- ### whatever the hell _that_ is -->
+ </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 # in search term</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>
+ </sect2>
+
+ <sect2 id="querymodel-regular">
+ <title>Zebra Regular Expressions in Truncation Attribute (type = 5)</title>
+
+ <para>
+ Each term in a query is interpreted as a regular expression if
+ the truncation value is either <emphasis>Regxp-1 (@attr 5=102)</emphasis>
+ or <emphasis>Regxp-2 (@attr 5=103)</emphasis>.
+ Both query types follow the same syntax with the operands:
+ </para>
+
+ <table id="querymodel-regular-operands-table">
+ <caption>Regular Expression Operands</caption>
+ <!--
+ <thead>
+ <tr><td>one</td><td>two</td></tr>
+ </thead>
+ -->
+ <tbody>
+ <tr>
+ <td><emphasis>x</emphasis></td>
+ <td>Matches the character <emphasis>x</emphasis>.</td>
+ </tr>
+ <tr>
+ <td><emphasis>.</emphasis></td>
+ <td>Matches any character.</td>
+ </tr>
+ <tr>
+ <td><emphasis>[ .. ]</emphasis></td>
+ <td>Matches the set of characters specified;
+ such as <literal>[abc]</literal> or <literal>[a-c]</literal>.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <para>
+ The above operands can be combined with the following operators:
+ </para>
+
+
+ <table id="querymodel-regular-operators-table">
+ <caption>Regular Expression Operators</caption>
+ <!--
+ <thead>
+ <tr><td>one</td><td>two</td></tr>
+ </thead>
+ -->
+ <tbody>
+ <tr>
+ <td><emphasis>x*</emphasis></td>
+ <td>Matches <emphasis>x</emphasis> zero or more times.
+ Priority: high.</td>
+ </tr>
+ <tr>
+ <td><emphasis>x+</emphasis></td>
+ <td>Matches <emphasis>x</emphasis> one or more times.
+ Priority: high.</td>
+ </tr>
+ <tr>
+ <td><emphasis>x?</emphasis></td>
+ <td> Matches <emphasis>x</emphasis> zero or once.
+ Priority: high.</td>
+ </tr>
+ <tr>
+ <td><emphasis>xy</emphasis></td>
+ <td> Matches <emphasis>x</emphasis>, then <emphasis>y</emphasis>.
+ Priority: medium.</td>
+ </tr>
+ <tr>
+ <td><emphasis>x|y</emphasis></td>
+ <td> Matches either <emphasis>x</emphasis> or <emphasis>y</emphasis>.
+ Priority: low.</td>
+ </tr>
+ <tr>
+ <td><emphasis>( )</emphasis></td>
+ <td>The order of evaluation may be changed by using parentheses.</td>
+ </tr>
+ </tbody>
+ </table>
+
+ <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>
+
+ <para>
+ For example, a phrase search with regular expressions in
+ the title-register is performed like this:
+ <screen>
+ Z> find @attr 1=4 @attr 5=102 "informat.* retrieval"
+ </screen>
+ </para>
+
+ <para>
+ Combinations with other attributes are possible. For example, a
+ ranked search with a regular expression
+ (see <xref linkend="administration-ranking"/> for the glory details):
+ <screen>
+ Z> find @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval"
+ </screen>
+ </para>
+ </sect2>
+
<!--
<para>
-<!--
- <sect1 id="architecture-querylanguage">
- <title>Query Languages</title>
-
- <para>
-
-http://www.loc.gov/z3950/agency/document.html
-
- PQF and BIB-1 stuff to be explained
- <ulink url="&url.z39.50.attset.bib1;">
- http://www.loc.gov/z3950/agency/defns/bib1.html</ulink>
-
- <ulink url="&url.z39.50.attset.bib1.1995;">
- http://www.loc.gov/z3950/agency/bib1.html</ulink>
-
- http://www.loc.gov/z3950/agency/markup/13.html
-
- </para>
- </sect1>
-
-
-These attribute types are recognized regardless of attribute set. Some are recognized for search, others for scan.
-
-Search
-
-Type Name Version
-7 Embedded Sort 1.1
-8 Term Set 1.1
-9 Rank weight 1.1
-9 Approx Limit 1.4
-10 Term Ref 1.4
-
-Embedded Sort
-
-The embedded sort is a way to specify sort within a query - thus removing the need to send a Sort Request separately. It is both faster and does not require clients that deal with the Sort Facility.
-
-The value after attribute type 7 is 1=ascending, 2=descending.. The attributes+term (APT) node is separate from the rest and must be @or'ed. The term associated with APT is the level .. 0=primary sort, 1=secondary sort etc.. Example:
-
-Search for water, sort by title (ascending):
-
- @or @attr 1=1016 water @attr 7=1 @attr 1=4 0
-
-Search for water, sort by title ascending, then date descending:
-
- @or @or @attr 1=1016 water @attr 7=1 @attr 1=4 0 @attr 7=2 @attr 1=30 1
-
-Term Set
-
-The Term Set feature is a facility that allows a search to store hitting terms in a "pseudo" resultset; thus a search (as usual) + a scan-like facility. Requires a client that can do named result sets since the search generates two result sets. The value for attribute 8 is the name of a result set (string). The terms in term set are returned as SUTRS records.
-
-Seach for u in title, right truncated.. Store result in result set named uset.
-
- @attr 5=1 @attr 1=4 @attr 8=uset u
-
-The model as one serious flaw.. We don't know the size of term set.
-
-Rank weight
-
-Rank weight is a way to pass a value to a ranking algorithm - so that one APT has one value - while another as a different one.
-
-Search for utah in title with weight 30 as well as any with weight 20.
-
- @attr 2=102 @or @attr 9=30 @attr 1=4 utah @attr 9=20 utah
-
-Approx Limit
-
-Newer Zebra versions normally estemiates hit count for every APT (leaf) in the query tree. These hit counts are returned as part of the searchResult-1 facility.
-
-By setting a limit for the APT we can make Zebra turn into approximate hit count when a certain hit count limit is reached. A value of zero means exact hit count.
-
-We are intersted in exact hit count for a, but for b we allow estimates for 1000 and higher..
-
- @and a @attr 9=1000 b
-
-This facility clashes with rank weight! Fortunately this is a Zebra 1.4 thing so we can change this without upsetting anybody!
-
-Term Ref
-
-Zebra supports the searchResult-1 facility.
-
-If attribute 10 is given, that specifies a subqueryId value returned as part of the search result. It is a way for a client to name an APT part of a query.
-
-Scan
-
-Type Name Version
-8 Result set narrow 1.3
-9 Approx Limit 1.4
-
-Result set narrow
-
-If attribute 8 is given for scan, the value is the name of a result set. Each hit count in scan is @and'ed with the result set given.
-
-Approx limit
-
-The approx (as for search) is a way to enable approx hit counts for scan hit counts. However, it does NOT appear to work at the moment.
-
-
- AdamDickmeiss - 19 Dec 2005
-
-
--->
-
</chapter>
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