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Improve docs of pg_trgm changes 

Artur Zakirov, per gripe from Jeff Janes
This commit is contained in:
Teodor Sigaev 2016-03-22 17:08:10 +03:00
parent 112a2d0615
commit f6bd0da63b
1 changed files with 37 additions and 21 deletions
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58
doc/src/sgml/pgtrgm.sgml
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@ -153,15 +153,22 @@
</entry>
</row>
<row>
<entry><type>text</> <literal>%&gt;</literal> <type>text</></entry>
<entry><type>boolean</type></entry>
<entry>
Returns <literal>true</> if its first argument has the similar word in
the second argument and they have a similarity that is greater than the
current word similarity threshold set by
<varname>pg_trgm.word_similarity_threshold</> parameter.
</entry>
</row>
<entry><type>text</> <literal>&lt;%</literal> <type>text</></entry>
<entry><type>boolean</type></entry>
<entry>
Returns <literal>true</> if its first argument has the similar word in
the second argument and they have a similarity that is greater than the
current word similarity threshold set by
<varname>pg_trgm.word_similarity_threshold</> parameter.
</entry>
</row>
<row>
<entry><type>text</> <literal>%&gt;</literal> <type>text</></entry>
<entry><type>boolean</type></entry>
<entry>
Commutator of the <literal>&lt;%</> operator.
</entry>
</row>
<row>
<entry><type>text</> <literal>&lt;-&gt;</literal> <type>text</></entry>
<entry><type>real</type></entry>
@ -171,14 +178,23 @@
</entry>
</row>
<row>
<entry>
<type>text</> <literal>&lt;-&gt;&gt;</literal> <type>text</>
</entry>
<entry><type>real</type></entry>
<entry>
Returns the <quote>distance</> between the arguments, that is
one minus the <function>word_similarity()</> value.
</entry>
<entry>
<type>text</> <literal>&lt;&lt;-&gt;</literal> <type>text</>
</entry>
<entry><type>real</type></entry>
<entry>
Returns the <quote>distance</> between the arguments, that is
one minus the <function>word_similarity()</> value.
</entry>
</row>
<row>
<entry>
<type>text</> <literal>&lt;-&gt;&gt;</literal> <type>text</>
</entry>
<entry><type>real</type></entry>
<entry>
Commutator of the <literal>&lt;&lt;-&gt;</> operator.
</entry>
</row>
</tbody>
</tgroup>
@ -215,8 +231,8 @@
<listitem>
<para>
Sets the current word similarity threshold that is used by
the <literal>%&gt;</> operator. The threshold must be between
0 and 1 (default is 0.6).
<literal>&lt;%</> and <literal>%&gt;</> operators. The threshold
must be between 0 and 1 (default is 0.6).
</para>
</listitem>
</varlistentry>
@ -283,7 +299,7 @@ SELECT t, t &lt;-&gt; '<replaceable>word</>' AS dist
<programlisting>
SELECT t, word_similarity('<replaceable>word</>', t) AS sml
FROM test_trgm
WHERE t %&gt; '<replaceable>word</>'
WHERE '<replaceable>word</>' &lt;% t
ORDER BY sml DESC, t;
</programlisting>
This will return all values in the text column that have a word
@ -295,7 +311,7 @@ SELECT t, word_similarity('<replaceable>word</>', t) AS sml
<para>
A variant of the above query is
<programlisting>
SELECT t, t &lt;-&gt;&gt; '<replaceable>word</>' AS dist
SELECT t, '<replaceable>word</>' &lt;&lt;-&gt; t AS dist
FROM test_trgm
ORDER BY dist LIMIT 10;
</programlisting>