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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:46:48 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:46:48 +0000 |
| commit | 311bcfc6b3acdd6fd152798c7f287ddf74fa2a98 (patch) | |
| tree | 0ec307299b1dada3701e42f4ca6eda57d708261e /doc/src/sgml/html/unaccent.html | |
| parent | Initial commit. (diff) | |
| download | postgresql-15-311bcfc6b3acdd6fd152798c7f287ddf74fa2a98.tar.xz postgresql-15-311bcfc6b3acdd6fd152798c7f287ddf74fa2a98.zip | |
Adding upstream version 15.4.upstream/15.4upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/html/unaccent.html')
| -rw-r--r-- | doc/src/sgml/html/unaccent.html | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/doc/src/sgml/html/unaccent.html b/doc/src/sgml/html/unaccent.html new file mode 100644 index 0000000..72554f8 --- /dev/null +++ b/doc/src/sgml/html/unaccent.html @@ -0,0 +1,131 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>F.48. unaccent</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="tsm-system-time.html" title="F.47. tsm_system_time" /><link rel="next" href="uuid-ossp.html" title="F.49. uuid-ossp" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">F.48. unaccent</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="tsm-system-time.html" title="F.47. tsm_system_time">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="contrib.html" title="Appendix F. Additional Supplied Modules">Up</a></td><th width="60%" align="center">Appendix F. Additional Supplied Modules</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="uuid-ossp.html" title="F.49. uuid-ossp">Next</a></td></tr></table><hr /></div><div class="sect1" id="UNACCENT"><div class="titlepage"><div><div><h2 class="title" style="clear: both">F.48. unaccent</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="unaccent.html#id-1.11.7.57.6">F.48.1. Configuration</a></span></dt><dt><span class="sect2"><a href="unaccent.html#id-1.11.7.57.7">F.48.2. Usage</a></span></dt><dt><span class="sect2"><a href="unaccent.html#id-1.11.7.57.8">F.48.3. Functions</a></span></dt></dl></div><a id="id-1.11.7.57.2" class="indexterm"></a><p> + <code class="filename">unaccent</code> is a text search dictionary that removes accents + (diacritic signs) from lexemes. + It's a filtering dictionary, which means its output is + always passed to the next dictionary (if any), unlike the normal + behavior of dictionaries. This allows accent-insensitive processing + for full text search. + </p><p> + The current implementation of <code class="filename">unaccent</code> cannot be used as a + normalizing dictionary for the <code class="filename">thesaurus</code> dictionary. + </p><p> + This module is considered <span class="quote">“<span class="quote">trusted</span>”</span>, that is, it can be + installed by non-superusers who have <code class="literal">CREATE</code> privilege + on the current database. + </p><div class="sect2" id="id-1.11.7.57.6"><div class="titlepage"><div><div><h3 class="title">F.48.1. Configuration</h3></div></div></div><p> + An <code class="literal">unaccent</code> dictionary accepts the following options: + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> + <code class="literal">RULES</code> is the base name of the file containing the list of + translation rules. This file must be stored in + <code class="filename">$SHAREDIR/tsearch_data/</code> (where <code class="literal">$SHAREDIR</code> means + the <span class="productname">PostgreSQL</span> installation's shared-data directory). + Its name must end in <code class="literal">.rules</code> (which is not to be included in + the <code class="literal">RULES</code> parameter). + </p></li></ul></div><p> + The rules file has the following format: + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> + Each line represents one translation rule, consisting of a character with + accent followed by a character without accent. The first is translated + into the second. For example, +</p><pre class="programlisting"> +À A +Á A +Â A +Ã A +Ä A +Å A +Æ AE +</pre><p> + The two characters must be separated by whitespace, and any leading or + trailing whitespace on a line is ignored. + </p></li><li class="listitem"><p> + Alternatively, if only one character is given on a line, instances of + that character are deleted; this is useful in languages where accents + are represented by separate characters. + </p></li><li class="listitem"><p> + Actually, each <span class="quote">“<span class="quote">character</span>”</span> can be any string not containing + whitespace, so <code class="filename">unaccent</code> dictionaries could be used for + other sorts of substring substitutions besides diacritic removal. + </p></li><li class="listitem"><p> + As with other <span class="productname">PostgreSQL</span> text search configuration files, + the rules file must be stored in UTF-8 encoding. The data is + automatically translated into the current database's encoding when + loaded. Any lines containing untranslatable characters are silently + ignored, so that rules files can contain rules that are not applicable in + the current encoding. + </p></li></ul></div><p> + A more complete example, which is directly useful for most European + languages, can be found in <code class="filename">unaccent.rules</code>, which is installed + in <code class="filename">$SHAREDIR/tsearch_data/</code> when the <code class="filename">unaccent</code> + module is installed. This rules file translates characters with accents + to the same characters without accents, and it also expands ligatures + into the equivalent series of simple characters (for example, Æ to + AE). + </p></div><div class="sect2" id="id-1.11.7.57.7"><div class="titlepage"><div><div><h3 class="title">F.48.2. Usage</h3></div></div></div><p> + Installing the <code class="literal">unaccent</code> extension creates a text + search template <code class="literal">unaccent</code> and a dictionary <code class="literal">unaccent</code> + based on it. The <code class="literal">unaccent</code> dictionary has the default + parameter setting <code class="literal">RULES='unaccent'</code>, which makes it immediately + usable with the standard <code class="filename">unaccent.rules</code> file. + If you wish, you can alter the parameter, for example + +</p><pre class="programlisting"> +mydb=# ALTER TEXT SEARCH DICTIONARY unaccent (RULES='my_rules'); +</pre><p> + + or create new dictionaries based on the template. + </p><p> + To test the dictionary, you can try: +</p><pre class="programlisting"> +mydb=# select ts_lexize('unaccent','Hôtel'); + ts_lexize +----------- + {Hotel} +(1 row) +</pre><p> + </p><p> + Here is an example showing how to insert the + <code class="filename">unaccent</code> dictionary into a text search configuration: +</p><pre class="programlisting"> +mydb=# CREATE TEXT SEARCH CONFIGURATION fr ( COPY = french ); +mydb=# ALTER TEXT SEARCH CONFIGURATION fr + ALTER MAPPING FOR hword, hword_part, word + WITH unaccent, french_stem; +mydb=# select to_tsvector('fr','Hôtels de la Mer'); + to_tsvector +------------------- + 'hotel':1 'mer':4 +(1 row) + +mydb=# select to_tsvector('fr','Hôtel de la Mer') @@ to_tsquery('fr','Hotels'); + ?column? +---------- + t +(1 row) + +mydb=# select ts_headline('fr','Hôtel de la Mer',to_tsquery('fr','Hotels')); + ts_headline +------------------------ + <b>Hôtel</b> de la Mer +(1 row) +</pre><p> + </p></div><div class="sect2" id="id-1.11.7.57.8"><div class="titlepage"><div><div><h3 class="title">F.48.3. Functions</h3></div></div></div><p> + The <code class="function">unaccent()</code> function removes accents (diacritic signs) from + a given string. Basically, it's a wrapper around + <code class="filename">unaccent</code>-type dictionaries, but it can be used outside normal + text search contexts. + </p><a id="id-1.11.7.57.8.3" class="indexterm"></a><pre class="synopsis"> +unaccent([<span class="optional"><em class="replaceable"><code>dictionary</code></em> <code class="type">regdictionary</code>, </span>] <em class="replaceable"><code>string</code></em> <code class="type">text</code>) returns <code class="type">text</code> +</pre><p> + If the <em class="replaceable"><code>dictionary</code></em> argument is + omitted, the text search dictionary named <code class="literal">unaccent</code> and + appearing in the same schema as the <code class="function">unaccent()</code> + function itself is used. + </p><p> + For example: +</p><pre class="programlisting"> +SELECT unaccent('unaccent', 'Hôtel'); +SELECT unaccent('Hôtel'); +</pre><p> + </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="tsm-system-time.html" title="F.47. tsm_system_time">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="contrib.html" title="Appendix F. 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