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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>CREATE OPERATOR CLASS</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="sql-createoperator.html" title="CREATE OPERATOR" /><link rel="next" href="sql-createopfamily.html" title="CREATE OPERATOR FAMILY" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">CREATE OPERATOR CLASS</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-createoperator.html" title="CREATE OPERATOR">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</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="sql-createopfamily.html" title="CREATE OPERATOR FAMILY">Next</a></td></tr></table><hr /></div><div class="refentry" id="SQL-CREATEOPCLASS"><div class="titlepage"></div><a id="id-1.9.3.73.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">CREATE OPERATOR CLASS</span></h2><p>CREATE OPERATOR CLASS — define a new operator class</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">3CREATE OPERATOR CLASS <em class="replaceable"><code>name</code></em> [ DEFAULT ] FOR TYPE <em class="replaceable"><code>data_type</code></em>4 USING <em class="replaceable"><code>index_method</code></em> [ FAMILY <em class="replaceable"><code>family_name</code></em> ] AS5 { OPERATOR <em class="replaceable"><code>strategy_number</code></em> <em class="replaceable"><code>operator_name</code></em> [ ( <em class="replaceable"><code>op_type</code></em>, <em class="replaceable"><code>op_type</code></em> ) ] [ FOR SEARCH | FOR ORDER BY <em class="replaceable"><code>sort_family_name</code></em> ]6 | FUNCTION <em class="replaceable"><code>support_number</code></em> [ ( <em class="replaceable"><code>op_type</code></em> [ , <em class="replaceable"><code>op_type</code></em> ] ) ] <em class="replaceable"><code>function_name</code></em> ( <em class="replaceable"><code>argument_type</code></em> [, ...] )7 | STORAGE <em class="replaceable"><code>storage_type</code></em>8 } [, ... ]9</pre></div><div class="refsect1" id="id-1.9.3.73.5"><h2>Description</h2><p>10 <code class="command">CREATE OPERATOR CLASS</code> creates a new operator class.11 An operator class defines how a particular data type can be used with12 an index. The operator class specifies that certain operators will fill13 particular roles or <span class="quote">“<span class="quote">strategies</span>”</span> for this data type and this14 index method. The operator class also specifies the support functions to15 be used by16 the index method when the operator class is selected for an17 index column. All the operators and functions used by an operator18 class must be defined before the operator class can be created.19 </p><p>20 If a schema name is given then the operator class is created in the21 specified schema. Otherwise it is created in the current schema.22 Two operator classes in the same schema can have the same name only if they23 are for different index methods.24 </p><p>25 The user who defines an operator class becomes its owner. Presently,26 the creating user must be a superuser. (This restriction is made because27 an erroneous operator class definition could confuse or even crash the28 server.)29 </p><p>30 <code class="command">CREATE OPERATOR CLASS</code> does not presently check31 whether the operator class definition includes all the operators and32 functions required by the index method, nor whether the operators and33 functions form a self-consistent set. It is the user's34 responsibility to define a valid operator class.35 </p><p>36 Related operator classes can be grouped into <em class="firstterm">operator37 families</em>. To add a new operator class to an existing family,38 specify the <code class="literal">FAMILY</code> option in <code class="command">CREATE OPERATOR39 CLASS</code>. Without this option, the new class is placed into40 a family named the same as the new class (creating that family if41 it doesn't already exist).42 </p><p>43 Refer to <a class="xref" href="xindex.html" title="38.16. Interfacing Extensions to Indexes">Section 38.16</a> for further information.44 </p></div><div class="refsect1" id="id-1.9.3.73.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>name</code></em></span></dt><dd><p>45 The name of the operator class to be created. The name can be46 schema-qualified.47 </p></dd><dt><span class="term"><code class="literal">DEFAULT</code></span></dt><dd><p>48 If present, the operator class will become the default49 operator class for its data type. At most one operator class50 can be the default for a specific data type and index method.51 </p></dd><dt><span class="term"><em class="replaceable"><code>data_type</code></em></span></dt><dd><p>52 The column data type that this operator class is for.53 </p></dd><dt><span class="term"><em class="replaceable"><code>index_method</code></em></span></dt><dd><p>54 The name of the index method this operator class is for.55 </p></dd><dt><span class="term"><em class="replaceable"><code>family_name</code></em></span></dt><dd><p>56 The name of the existing operator family to add this operator class to.57 If not specified, a family named the same as the operator class is58 used (creating it, if it doesn't already exist).59 </p></dd><dt><span class="term"><em class="replaceable"><code>strategy_number</code></em></span></dt><dd><p>60 The index method's strategy number for an operator61 associated with the operator class.62 </p></dd><dt><span class="term"><em class="replaceable"><code>operator_name</code></em></span></dt><dd><p>63 The name (optionally schema-qualified) of an operator associated64 with the operator class.65 </p></dd><dt><span class="term"><em class="replaceable"><code>op_type</code></em></span></dt><dd><p>66 In an <code class="literal">OPERATOR</code> clause,67 the operand data type(s) of the operator, or <code class="literal">NONE</code> to68 signify a prefix operator. The operand data69 types can be omitted in the normal case where they are the same70 as the operator class's data type.71 </p><p>72 In a <code class="literal">FUNCTION</code> clause, the operand data type(s) the73 function is intended to support, if different from74 the input data type(s) of the function (for B-tree comparison functions75 and hash functions)76 or the class's data type (for B-tree sort support functions,77 B-tree equal image functions, and all functions in GiST,78 SP-GiST, GIN and BRIN operator classes). These defaults are79 correct, and so <em class="replaceable"><code>op_type</code></em> need not be specified80 in <code class="literal">FUNCTION</code> clauses, except for the case of a81 B-tree sort support function that is meant to support82 cross-data-type comparisons.83 </p></dd><dt><span class="term"><em class="replaceable"><code>sort_family_name</code></em></span></dt><dd><p>84 The name (optionally schema-qualified) of an existing <code class="literal">btree</code> operator85 family that describes the sort ordering associated with an ordering86 operator.87 </p><p>88 If neither <code class="literal">FOR SEARCH</code> nor <code class="literal">FOR ORDER BY</code> is89 specified, <code class="literal">FOR SEARCH</code> is the default.90 </p></dd><dt><span class="term"><em class="replaceable"><code>support_number</code></em></span></dt><dd><p>91 The index method's support function number for a92 function associated with the operator class.93 </p></dd><dt><span class="term"><em class="replaceable"><code>function_name</code></em></span></dt><dd><p>94 The name (optionally schema-qualified) of a function that is an95 index method support function for the operator class.96 </p></dd><dt><span class="term"><em class="replaceable"><code>argument_type</code></em></span></dt><dd><p>97 The parameter data type(s) of the function.98 </p></dd><dt><span class="term"><em class="replaceable"><code>storage_type</code></em></span></dt><dd><p>99 The data type actually stored in the index. Normally this is100 the same as the column data type, but some index methods101 (currently GiST, GIN, SP-GiST and BRIN) allow it to be different. The102 <code class="literal">STORAGE</code> clause must be omitted unless the index103 method allows a different type to be used.104 If the column <em class="replaceable"><code>data_type</code></em> is specified105 as <code class="type">anyarray</code>, the <em class="replaceable"><code>storage_type</code></em>106 can be declared as <code class="type">anyelement</code> to indicate that the index107 entries are members of the element type belonging to the actual array108 type that each particular index is created for.109 </p></dd></dl></div><p>110 The <code class="literal">OPERATOR</code>, <code class="literal">FUNCTION</code>, and <code class="literal">STORAGE</code>111 clauses can appear in any order.112 </p></div><div class="refsect1" id="id-1.9.3.73.7"><h2>Notes</h2><p>113 Because the index machinery does not check access permissions on functions114 before using them, including a function or operator in an operator class115 is tantamount to granting public execute permission on it. This is usually116 not an issue for the sorts of functions that are useful in an operator117 class.118 </p><p>119 The operators should not be defined by SQL functions. An SQL function120 is likely to be inlined into the calling query, which will prevent121 the optimizer from recognizing that the query matches an index.122 </p><p>123 Before <span class="productname">PostgreSQL</span> 8.4, the <code class="literal">OPERATOR</code>124 clause could include a <code class="literal">RECHECK</code> option. This is no longer125 supported because whether an index operator is <span class="quote">“<span class="quote">lossy</span>”</span> is now126 determined on-the-fly at run time. This allows efficient handling of127 cases where an operator might or might not be lossy.128 </p></div><div class="refsect1" id="id-1.9.3.73.8"><h2>Examples</h2><p>129 The following example command defines a GiST index operator class130 for the data type <code class="literal">_int4</code> (array of <code class="type">int4</code>). See the131 <a class="xref" href="intarray.html" title="F.20. intarray — manipulate arrays of integers">intarray</a> module for the complete example.132 </p><pre class="programlisting">133CREATE OPERATOR CLASS gist__int_ops134 DEFAULT FOR TYPE _int4 USING gist AS135 OPERATOR 3 &&,136 OPERATOR 6 = (anyarray, anyarray),137 OPERATOR 7 @>,138 OPERATOR 8 <@,139 OPERATOR 20 @@ (_int4, query_int),140 FUNCTION 1 g_int_consistent (internal, _int4, smallint, oid, internal),141 FUNCTION 2 g_int_union (internal, internal),142 FUNCTION 3 g_int_compress (internal),143 FUNCTION 4 g_int_decompress (internal),144 FUNCTION 5 g_int_penalty (internal, internal, internal),145 FUNCTION 6 g_int_picksplit (internal, internal),146 FUNCTION 7 g_int_same (_int4, _int4, internal);147</pre></div><div class="refsect1" id="id-1.9.3.73.9"><h2>Compatibility</h2><p>148 <code class="command">CREATE OPERATOR CLASS</code> is a149 <span class="productname">PostgreSQL</span> extension. There is no150 <code class="command">CREATE OPERATOR CLASS</code> statement in the SQL151 standard.152 </p></div><div class="refsect1" id="id-1.9.3.73.10"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-alteropclass.html" title="ALTER OPERATOR CLASS"><span class="refentrytitle">ALTER OPERATOR CLASS</span></a>, <a class="xref" href="sql-dropopclass.html" title="DROP OPERATOR CLASS"><span class="refentrytitle">DROP OPERATOR CLASS</span></a>, <a class="xref" href="sql-createopfamily.html" title="CREATE OPERATOR FAMILY"><span class="refentrytitle">CREATE OPERATOR FAMILY</span></a>, <a class="xref" href="sql-alteropfamily.html" title="ALTER OPERATOR FAMILY"><span class="refentrytitle">ALTER OPERATOR FAMILY</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-createoperator.html" title="CREATE OPERATOR">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-createopfamily.html" title="CREATE OPERATOR FAMILY">Next</a></td></tr><tr><td width="40%" align="left" valign="top">CREATE OPERATOR </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"> CREATE OPERATOR FAMILY</td></tr></table></div></body></html>