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Add websearch_to_tsquery

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Error-tolerant conversion function with web-like syntax for search query,
it simplifies  constraining search engine with close to habitual interface for
users.

Bump catalog version

Authors: Victor Drobny, Dmitry Ivanov with editorization by me
Reviewed by: Aleksander Alekseev, Tomas Vondra, Thomas Munro, Aleksandr Parfenov
Discussion: https://www.postgresql.org/message-id/flat/fe931111ff7e9ad79196486ada79e268@postgrespro.ru
This commit is contained in:
Teodor Sigaev
2018-04-05 19:55:11 +03:00
parent fbc27330b8
commit 1664ae1978
11 changed files with 1002 additions and 121 deletions
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12
doc/src/sgml/func.sgml
View File

@ -9630,6 +9630,18 @@ CREATE TYPE rainbow AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'purple
<entry><literal>phraseto_tsquery('english', 'The Fat Rats')</literal></entry>
<entry><literal>'fat' &lt;-&gt; 'rat'</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>websearch_to_tsquery</primary>
</indexterm>
<literal><function>websearch_to_tsquery(<optional> <replaceable class="parameter">config</replaceable> <type>regconfig</type> , </optional> <replaceable class="parameter">query</replaceable> <type>text</type>)</function></literal>
</entry>
<entry><type>tsquery</type></entry>
<entry>produce <type>tsquery</type> from a web search style query</entry>
<entry><literal>websearch_to_tsquery('english', '"fat rat" or rat')</literal></entry>
<entry><literal>'fat' &lt;-&gt; 'rat' | 'rat'</literal></entry>
</row>
<row>
<entry>
<indexterm>

92
doc/src/sgml/textsearch.sgml
View File

@ -797,13 +797,16 @@ UPDATE tt SET ti =
<para>
<productname>PostgreSQL</productname> provides the
functions <function>to_tsquery</function>,
<function>plainto_tsquery</function>, and
<function>phraseto_tsquery</function>
<function>plainto_tsquery</function>,
<function>phraseto_tsquery</function> and
<function>websearch_to_tsquery</function>
for converting a query to the <type>tsquery</type> data type.
<function>to_tsquery</function> offers access to more features
than either <function>plainto_tsquery</function> or
<function>phraseto_tsquery</function>, but it is less forgiving
about its input.
<function>phraseto_tsquery</function>, but it is less forgiving about its
input. <function>websearch_to_tsquery</function> is a simplified version
of <function>to_tsquery</function> with an alternative syntax, similar
to the one used by web search engines.
</para>
<indexterm>
@ -962,6 +965,87 @@ SELECT phraseto_tsquery('english', 'The Fat &amp; Rats:C');
</screen>
</para>
<synopsis>
websearch_to_tsquery(<optional> <replaceable class="parameter">config</replaceable> <type>regconfig</type>, </optional> <replaceable class="parameter">querytext</replaceable> <type>text</type>) returns <type>tsquery</type>
</synopsis>
<para>
<function>websearch_to_tsquery</function> creates a <type>tsquery</type>
value from <replaceable>querytext</replaceable> using an alternative
syntax in which simple unformatted text is a valid query.
Unlike <function>plainto_tsquery</function>
and <function>phraseto_tsquery</function>, it also recognizes certain
operators. Moreover, this function should never raise syntax errors,
which makes it possible to use raw user-supplied input for search.
The following syntax is supported:
<itemizedlist spacing="compact" mark="bullet">
<listitem>
<para>
<literal>unquoted text</literal>: text not inside quote marks will be
converted to terms separated by <literal>&amp;</literal> operators, as
if processed by
<function>plainto_tsquery</function>.
</para>
</listitem>
<listitem>
<para>
<literal>"quoted text"</literal>: text inside quote marks will be
converted to terms separated by <literal>&lt;-&gt;</literal>
operators, as if processed by <function>phraseto_tsquery</function>.
</para>
</listitem>
<listitem>
<para>
<literal>OR</literal>: logical or will be converted to
the <literal>|</literal> operator.
</para>
</listitem>
<listitem>
<para>
<literal>-</literal>: the logical not operator, converted to the
the <literal>!</literal> operator.
</para>
</listitem>
</itemizedlist>
</para>
<para>
Examples:
<screen>
select websearch_to_tsquery('english', 'The fat rats');
websearch_to_tsquery
-----------------
'fat' &amp; 'rat'
(1 row)
</screen>
<screen>
select websearch_to_tsquery('english', '"supernovae stars" -crab');
websearch_to_tsquery
----------------------------------
'supernova' &lt;-&gt; 'star' &amp; !'crab'
(1 row)
</screen>
<screen>
select websearch_to_tsquery('english', '"sad cat" or "fat rat"');
websearch_to_tsquery
-----------------------------------
'sad' &lt;-&gt; 'cat' | 'fat' &lt;-&gt; 'rat'
(1 row)
</screen>
<screen>
select websearch_to_tsquery('english', 'signal -"segmentation fault"');
websearch_to_tsquery
---------------------------------------
'signal' &amp; !( 'segment' &lt;-&gt; 'fault' )
(1 row)
</screen>
<screen>
select websearch_to_tsquery('english', '""" )( dummy \\ query &lt;-&gt;');
websearch_to_tsquery
----------------------
'dummi' &amp; 'queri'
(1 row)
</screen>
</para>
</sect2>
<sect2 id="textsearch-ranking">