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<book id="marc_indexing">
<bookinfo>
 <title>Indexing of &acro.marc; records by &zebra;</title>
 <abstract>
  <simpara>&zebra; is suitable for distribution of &acro.marc; records via &acro.z3950;. We
	have a several possibilities to describe the indexing process of &acro.marc; records.
	This document shows these possibilities.
  </simpara>
 </abstract>
</bookinfo>

<chapter id="simple">
 <title>Simple indexing of &acro.marc; records</title>
<para>Simple indexing is not described yet.</para>
</chapter>

<chapter id="extended">
 <title>Extended indexing of &acro.marc; records</title>

<para>Extended indexing of &acro.marc; records will help you if you need index a
combination of subfields, or index only a part of the whole field,
or use during indexing process embedded fields of &acro.marc; record.
</para>

<para>Extended indexing of &acro.marc; records additionally allows:
<itemizedlist>

<listitem>
<para>to index data in LEADER of &acro.marc; record</para>
</listitem>

<listitem>
<para>to index data in control fields (with fixed length)</para>
</listitem>

<listitem>
<para>to use during indexing the values of indicators</para>
</listitem>

<listitem>
<para>to index linked fields for UNI&acro.marc; based formats</para>
</listitem>

</itemizedlist>
</para>

<note><para>In compare with simple indexing process the extended indexing
may increase (about 2-3 times) the time of indexing process for &acro.marc;
records.</para></note>

<sect1 id="formula">
<title>The index-formula</title>

<para>At the beginning, we have to define the term <emphasis>index-formula</emphasis>
for &acro.marc; records. This term helps to understand the notation of extended indexing of MARC records
by &zebra;. Our definition is based on the document <ulink url="http://www.rba.ru/rusmarc/soft/Z39-50.htm">"The
table of conformity for &acro.z3950; use attributes and R&acro.usmarc; fields"</ulink>.
The document is available only in Russian language.</para>

<para>The <emphasis>index-formula</emphasis> is the combination of subfields presented in such way:</para>

<screen>
71-00$a, $g, $h ($c){.$b ($c)} , (1)
</screen>

<para>We know that &zebra; supports a &acro.bib1; attribute - right truncation.
In this case, the <emphasis>index-formula</emphasis> (1) consists from 
forms, defined in the same way as (1)</para>

<screen>
71-00$a, $g, $h
71-00$a, $g
71-00$a
</screen>

<note><para>The original &acro.marc; record may be without some elements, which included in <emphasis>index-formula</emphasis>.</para>
</note>

<para>This notation includes such operands as:
<variablelist>

<varlistentry>
 <term>#</term>
 <listitem><para>It means whitespace character.</para></listitem>
</varlistentry>

<varlistentry>
 <term>-</term>
 <listitem><para>The position may contain any value, defined by &acro.marc; format.
 For example, <emphasis>index-formula</emphasis></para>

<screen>
70-#1$a, $g , (2)
</screen>

<para>includes</para> 

<screen>
700#1$a, $g
701#1$a, $g
702#1$a, $g
</screen>

</listitem>
</varlistentry>

<varlistentry>
<term>{...}</term>
<listitem><para>The repeatable elements are defined in figure-brackets {}. For example,
<emphasis>index-formula</emphasis></para>


<screen>
71-00$a, $g, $h ($c){.$b ($c)} , (3)
</screen>

<para>includes</para>

<screen>
71-00$a, $g, $h ($c). $b ($c)
71-00$a, $g, $h ($c). $b ($c). $b ($c)
71-00$a, $g, $h ($c). $b ($c). $b ($c). $b ($c)
</screen>

</listitem>
</varlistentry>
</variablelist>

<note><para>All another operands are the same as accepted in &acro.marc; world.</para>
</note>
</para>
</sect1>

<sect1 id="notation">
<title>Notation of <emphasis>index-formula</emphasis> for &zebra;</title>


<para>Extended indexing overloads <literal>path</literal> of
<literal>elm</literal> definition in abstract syntax file of &zebra;
(<literal>.abs</literal> file). It means that names beginning with
<literal>"mc-"</literal> are interpreted by &zebra; as
<emphasis>index-formula</emphasis>. The database index is created and
linked with <emphasis>access point</emphasis> (&acro.bib1; use attribute)
according to this formula.</para>

<para>For example, <emphasis>index-formula</emphasis></para>

<screen>
71-00$a, $g, $h ($c){.$b ($c)} , (4)
</screen>

<para>in <literal>.abs</literal> file looks like:</para>

<screen>
mc-71.00_$a,_$g,_$h_(_$c_){.$b_(_$c_)}
</screen>


<para>The notation of <emphasis>index-formula</emphasis> uses the operands:
<variablelist>

<varlistentry>
<term>_</term>
<listitem><para>It means whitespace character.</para></listitem>
</varlistentry>

<varlistentry>
<term>.</term>
<listitem><para>The position may contain any value, defined by &acro.marc; format. For example,
<emphasis>index-formula</emphasis></para>

<screen>
70-#1$a, $g , (5)
</screen>

<para>matches <literal>mc-70._1_$a,_$g_</literal> and includes</para>

<screen>
700_1_$a,_$g_
701_1_$a,_$g_
702_1_$a,_$g_
</screen>
</listitem>
</varlistentry>

<varlistentry>
<term>{...}</term>
<listitem><para>The repeatable elements are defined in figure-brackets {}. For example,
<emphasis>index-formula</emphasis></para>

<screen>
71#00$a, $g, $h ($c) {.$b ($c)} , (6)
</screen>

<para>matches <literal>mc-71.00_$a,_$g,_$h_(_$c_){.$b_(_$c_)}</literal> and
includes</para>

<screen>
71.00_$a,_$g,_$h_(_$c_).$b_(_$c_)
71.00_$a,_$g,_$h_(_$c_).$b_(_$c_).$b_(_$c_)
71.00_$a,_$g,_$h_(_$c_).$b_(_$c_).$b_(_$c_).$b_(_$c_)
</screen>
</listitem>
</varlistentry>


<varlistentry>
<term>&#60;...&#62;</term>
<listitem><para>Embedded <emphasis>index-formula</emphasis> (for linked fields) is between &#60;&#62;. For example,
<emphasis>index-formula</emphasis></para>

<screen>
4--#-$170-#1$a, $g ($c) , (7)
</screen>

<para>matches <literal>mc-4.._._$1&#60;70._1_$a,_$g_(_$c_)&#62;_</literal> and
includes</para>

<screen>
463_._$1&#60;70._1_$a,_$g_(_$c_)&#62;_
</screen>

</listitem>
</varlistentry>
</variablelist>
</para>

<note>
<para>All another operands are the same as accepted in &acro.marc; world.</para>
</note>

<sect2>
<title>Examples</title>

<para>
<orderedlist>

<listitem>

<para>indexing LEADER</para>

<para>You need to use keyword "ldr" to index leader. For example, indexing data from 6th
and 7th position of LEADER</para>

<screen>
elm mc-ldr[6] Record-type !
elm mc-ldr[7] Bib-level   !
</screen>

</listitem>

<listitem>

<para>indexing data from control fields</para>

<para>indexing date (the time added to database)</para>

<screen>
elm mc-008[0-5] Date/time-added-to-db !	
</screen>

<para>or for R&acro.usmarc; (this data included in 100th field)</para>

<screen>
elm mc-100___$a[0-7]_ Date/time-added-to-db !
</screen>

</listitem>

<listitem>

<para>using indicators while indexing</para>

<para>For R&acro.usmarc; <emphasis>index-formula</emphasis>
<literal>70-#1$a, $g</literal> matches</para>

<screen>
elm 70._1_$a,_$g_ Author !:w,!:p
</screen>

<para>When &zebra; finds a field according to <literal>"70."</literal> pattern it checks
the indicators.  In this case the value of first indicator doesn't mater, but
the value of second one must be whitespace, in another case a field is not 
indexed.</para>

</listitem>

<listitem>

<para>indexing embedded (linked) fields for UNI&acro.marc; based formats</para>

<para>For R&acro.usmarc; <emphasis>index-formula</emphasis> 
<literal>4--#-$170-#1$a, $g ($c)</literal> matches</para>

<screen>
elm mc-4.._._$1<70._1_$a,_$g_(_$c_)>_ Author !:w,!:p
</screen>

<para>Data are extracted from record if the field matches to
<literal>"4.._."</literal> pattern and data in linked field match to embedded
<emphasis>index-formula</emphasis> <literal>70._1_$a,_$g_(_$c_)</literal>.</para>

</listitem>

</orderedlist>
</para>


</sect2>
</sect1>

</chapter>
</book>