Move full text search operators, functions, and data type sections into

the main documentation, out of its own text search chapter.

doc/src/sgml/datatype.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.207 2007/08/21 01:11:11 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.208 2007/08/29 20:37:14 momjian Exp $ -->
 
  <chapter id="datatype">
   <title id="datatype-title">Data Types</title>
@@ -234,6 +234,18 @@
        <entry>date and time, including time zone</entry>
       </row>
 
+      <row>
+       <entry><type>tsquery</type></entry>
+       <entry></entry>
+       <entry>full text search query</entry>
+      </row>
+
+      <row>
+       <entry><type>tsvector</type></entry>
+       <entry></entry>
+       <entry>full text search document</entry>
+      </row>
+
       <row>
        <entry><type>uuid</type></entry>
        <entry></entry>
@@ -3264,6 +3276,137 @@ a0eebc999c0b4ef8bb6d6bb9bd380a11
    </para>
   </sect1>
 
+  <sect1 id="datatype-textsearch">
+   <title>Full Text Search</title>
+
+   <variablelist>
+
+   <indexterm zone="datatype-textsearch">
+   <primary>tsvector</primary>
+   </indexterm>
+
+    <varlistentry>
+    <term><firstterm>tsvector</firstterm></term>
+     <listitem>
+
+      <para>
+       <type>tsvector</type> is a data type that represents a document and is
+       optimized for full text searching. In the simplest case,
+       <type>tsvector</type> is a sorted list of lexemes, so even without indexes
+       full text searches perform better than standard <literal>~</literal> and
+       <literal>LIKE</literal> operations:
+
+<programlisting>
+SELECT 'a fat cat sat on a mat and ate a fat rat'::tsvector;
+                      tsvector
+----------------------------------------------------
+ 'a' 'on' 'and' 'ate' 'cat' 'fat' 'mat' 'rat' 'sat'
+</programlisting>
+
+       Notice, that <literal>space</literal> is also a lexeme:
+
+<programlisting>
+SELECT 'space ''    '' is a lexeme'::tsvector;
+             tsvector
+----------------------------------
+ 'a' 'is' '    ' 'space' 'lexeme'
+</programlisting>
+
+       Each lexeme, optionally, can have positional information which is used for
+       <varname>proximity ranking</varname>:
+
+<programlisting>
+SELECT 'a:1 fat:2 cat:3 sat:4 on:5 a:6 mat:7 and:8 ate:9 a:10 fat:11 rat:12'::tsvector;
+                                  tsvector
+-------------------------------------------------------------------------------
+ 'a':1,6,10 'on':5 'and':8 'ate':9 'cat':3 'fat':2,11 'mat':7 'rat':12 'sat':4
+</programlisting>
+
+       Each lexeme position also can be labeled as <literal>A</literal>,
+       <literal>B</literal>, <literal>C</literal>, <literal>D</literal>,
+       where <literal>D</literal> is the default. These labels can be used to group
+       lexemes into different <emphasis>importance</emphasis> or
+       <emphasis>rankings</emphasis>, for example to reflect document structure.
+       Actual values can be assigned at search time and used during the calculation
+       of the document rank.  This is very useful for controlling search results.
+      </para>
+
+      <para>
+       The concatenation operator, e.g. <literal>tsvector || tsvector</literal>,
+       can "construct" a document from several parts. The order is important if
+       <type>tsvector</type> contains positional information. Of course,
+       it is also possible to build a document using different tables:
+
+<programlisting>
+SELECT 'fat:1 cat:2'::tsvector || 'fat:1 rat:2'::tsvector;
+         ?column?
+---------------------------
+ 'cat':2 'fat':1,3 'rat':4
+
+SELECT 'fat:1 rat:2'::tsvector || 'fat:1 cat:2'::tsvector;
+         ?column?
+---------------------------
+ 'cat':4 'fat':1,3 'rat':2
+</programlisting>
+
+      </para>
+
+     </listitem>
+
+    </varlistentry>
+
+    <indexterm zone="datatype-textsearch">
+    <primary>tsquery</primary>
+    </indexterm>
+
+    <varlistentry>
+    <term><firstterm>tsquery</firstterm></term>
+     <listitem>
+
+      <para>
+       <type>tsquery</type> is a data type for textual queries which supports
+       the boolean operators <literal>&amp;</literal> (AND), <literal>|</literal> (OR),
+       and parentheses.  A <type>tsquery</type> consists of lexemes
+       (optionally labeled by letters) with boolean operators in between:
+
+<programlisting>
+SELECT 'fat &amp; cat'::tsquery;
+    tsquery
+---------------
+ 'fat' &amp; 'cat'
+SELECT 'fat:ab &amp; cat'::tsquery;
+    tsquery
+------------------
+ 'fat':AB &amp; 'cat'
+</programlisting>
+
+       Labels can be used to restrict the search region, which allows the
+       development of different search engines using the same full text index.
+      </para>
+
+      <para>
+       <type>tsqueries</type> can be concatenated using <literal>&amp;&amp;</literal> (AND)
+       and <literal>||</literal> (OR) operators:
+
+<programlisting>
+SELECT 'a &amp; b'::tsquery &amp;&amp; 'c | d'::tsquery;
+         ?column?
+---------------------------
+ 'a' &amp; 'b' &amp; ( 'c' | 'd' )
+
+SELECT 'a &amp; b'::tsquery || 'c|d'::tsquery;
+         ?column?
+---------------------------
+ 'a' &amp; 'b' | ( 'c' | 'd' )
+</programlisting>
+
+      </para>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+
+  </sect1>
+
   <sect1 id="datatype-xml">
    <title><acronym>XML</> Type</title>