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1<?xml version="1.0" encoding="UTF-8" standalone="no"?>2<!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>37.7. character_sets</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="infoschema-attributes.html" title="37.6. attributes" /><link rel="next" href="infoschema-check-constraint-routine-usage.html" title="37.8. check_constraint_routine_usage" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">37.7. <code class="literal">character_sets</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="infoschema-attributes.html" title="37.6. attributes">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="information-schema.html" title="Chapter 37. The Information Schema">Up</a></td><th width="60%" align="center">Chapter 37. The Information Schema</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="infoschema-check-constraint-routine-usage.html" title="37.8. check_constraint_routine_usage">Next</a></td></tr></table><hr /></div><div class="sect1" id="INFOSCHEMA-CHARACTER-SETS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">37.7. <code class="literal">character_sets</code> <a href="#INFOSCHEMA-CHARACTER-SETS" class="id_link">#</a></h2></div></div></div><p>3   The view <code class="literal">character_sets</code> identifies the character4   sets available in the current database.  Since PostgreSQL does not5   support multiple character sets within one database, this view only6   shows one, which is the database encoding.7  </p><p>8   Take note of how the following terms are used in the SQL standard:9   </p><div class="variablelist"><dl class="variablelist"><dt><span class="term">character repertoire</span></dt><dd><p>10       An abstract collection of characters, for11       example <code class="literal">UNICODE</code>, <code class="literal">UCS</code>, or12       <code class="literal">LATIN1</code>.  Not exposed as an SQL object, but13       visible in this view.14      </p></dd><dt><span class="term">character encoding form</span></dt><dd><p>15       An encoding of some character repertoire.  Most older character16       repertoires only use one encoding form, and so there are no17       separate names for them (e.g., <code class="literal">LATIN2</code> is an18       encoding form applicable to the <code class="literal">LATIN2</code>19       repertoire).  But for example Unicode has the encoding forms20       <code class="literal">UTF8</code>, <code class="literal">UTF16</code>, etc. (not21       all supported by PostgreSQL).  Encoding forms are not exposed22       as an SQL object, but are visible in this view.23      </p></dd><dt><span class="term">character set</span></dt><dd><p>24       A named SQL object that identifies a character repertoire, a25       character encoding, and a default collation.  A predefined26       character set would typically have the same name as an encoding27       form, but users could define other names.  For example, the28       character set <code class="literal">UTF8</code> would typically identify29       the character repertoire <code class="literal">UCS</code>, encoding30       form <code class="literal">UTF8</code>, and some default collation.31      </p></dd></dl></div><p>32 33   You can think of an <span class="quote">“<span class="quote">encoding</span>”</span> in PostgreSQL either as34   a character set or a character encoding form.  They will have the35   same name, and there can only be one in one database.36  </p><div class="table" id="id-1.7.6.11.4"><p class="title"><strong>Table 37.5. <code class="structname">character_sets</code> Columns</strong></p><div class="table-contents"><table class="table" summary="character_sets Columns" border="1"><colgroup><col /></colgroup><thead><tr><th class="catalog_table_entry"><p class="column_definition">37       Column Type38      </p>39      <p>40       Description41      </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition">42       <code class="structfield">character_set_catalog</code> <code class="type">sql_identifier</code>43      </p>44      <p>45       Character sets are currently not implemented as schema objects, so this column is null.46      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">47       <code class="structfield">character_set_schema</code> <code class="type">sql_identifier</code>48      </p>49      <p>50       Character sets are currently not implemented as schema objects, so this column is null.51      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">52       <code class="structfield">character_set_name</code> <code class="type">sql_identifier</code>53      </p>54      <p>55       Name of the character set, currently implemented as showing the name of the database encoding56      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">57       <code class="structfield">character_repertoire</code> <code class="type">sql_identifier</code>58      </p>59      <p>60       Character repertoire, showing <code class="literal">UCS</code> if the encoding is <code class="literal">UTF8</code>, else just the encoding name61      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">62       <code class="structfield">form_of_use</code> <code class="type">sql_identifier</code>63      </p>64      <p>65       Character encoding form, same as the database encoding66      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">67       <code class="structfield">default_collate_catalog</code> <code class="type">sql_identifier</code>68      </p>69      <p>70       Name of the database containing the default collation (always the current database, if any collation is identified)71      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">72       <code class="structfield">default_collate_schema</code> <code class="type">sql_identifier</code>73      </p>74      <p>75       Name of the schema containing the default collation76      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">77       <code class="structfield">default_collate_name</code> <code class="type">sql_identifier</code>78      </p>79      <p>80       Name of the default collation.  The default collation is81       identified as the collation that matches82       the <code class="literal">COLLATE</code> and <code class="literal">CTYPE</code>83       settings of the current database.  If there is no such84       collation, then this column and the associated schema and85       catalog columns are null.86      </p></td></tr></tbody></table></div></div><br class="table-break" /></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="infoschema-attributes.html" title="37.6. attributes">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="information-schema.html" title="Chapter 37. The Information Schema">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="infoschema-check-constraint-routine-usage.html" title="37.8. check_constraint_routine_usage">Next</a></td></tr><tr><td width="40%" align="left" valign="top">37.6. <code class="literal">attributes</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 37.8. <code class="literal">check_constraint_routine_usage</code></td></tr></table></div></body></html>