1CREATE OPERATOR CLASS() SQL Commands CREATE OPERATOR CLASS()
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6 CREATE OPERATOR CLASS - define a new operator class
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10 CREATE OPERATOR CLASS name [ DEFAULT ] FOR TYPE data_type USING index_method AS
11 { OPERATOR strategy_number operator_name [ ( op_type, op_type ) ] [ RECHECK ]
12 | FUNCTION support_number funcname ( argument_type [, ...] )
13 | STORAGE storage_type
14 } [, ... ]
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18 CREATE OPERATOR CLASS creates a new operator class. An operator class
19 defines how a particular data type can be used with an index. The oper‐
20 ator class specifies that certain operators will fill particular roles
21 or ``strategies'' for this data type and this index method. The opera‐
22 tor class also specifies the support procedures to be used by the index
23 method when the operator class is selected for an index column. All the
24 operators and functions used by an operator class must be defined
25 before the operator class is created.
26 If a schema name is given then the operator class is created in the
28 specified schema. Otherwise it is created in the current schema. Two
29 operator classes in the same schema can have the same name only if they
30 are for different index methods.
31 The user who defines an operator class becomes its owner. Presently,
33 the creating user must be a superuser. (This restriction is made
34 because an erroneous operator class definition could confuse or even
35 crash the server.)
36 CREATE OPERATOR CLASS does not presently check whether the operator
38 class definition includes all the operators and functions required by
39 the index method, nor whether the operators and functions form a self-
40 consistent set. It is the user's responsibility to define a valid oper‐
41 ator class.
42 Refer to in the documentation for further information.
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46 name The name of the operator class to be created. The name may be
47 schema-qualified.
48 DEFAULT
50 If present, the operator class will become the default operator
51 class for its data type. At most one operator class can be the
52 default for a specific data type and index method.
53 data_type
55 The column data type that this operator class is for.
56 index_method
58 The name of the index method this operator class is for.
59 strategy_number
61 The index method's strategy number for an operator associated
62 with the operator class.
63 operator_name
65 The name (optionally schema-qualified) of an operator associated
66 with the operator class.
67 op_type
69 The operand data type(s) of an operator, or NONE to signify a
70 left-unary or right-unary operator. The operand data types may
71 be omitted in the normal case where they are the same as the
72 operator class's data type.
73 RECHECK
75 If present, the index is ``lossy'' for this operator, and so the
76 rows retrieved using the index must be rechecked to verify that
77 they actually satisfy the qualification clause involving this
78 operator.
79 support_number
81 The index method's support procedure number for a function asso‐
82 ciated with the operator class.
83 funcname
85 The name (optionally schema-qualified) of a function that is an
86 index method support procedure for the operator class.
87 argument_types
89 The parameter data type(s) of the function.
90 storage_type
92 The data type actually stored in the index. Normally this is the
93 same as the column data type, but some index methods (GIN and
94 GiST for now) allow it to be different. The STORAGE clause must
95 be omitted unless the index method allows a different type to be
96 used.
97 The OPERATOR, FUNCTION, and STORAGE clauses may appear in any order.
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101 Because the index machinery does not check access permissions on func‐
102 tions before using them, including a function or operator in an opera‐
103 tor class is tantamount to granting public execute permission on it.
104 This is usually not an issue for the sorts of functions that are useful
105 in an operator class.
106 The operators should not be defined by SQL functions. A SQL function is
108 likely to be inlined into the calling query, which will prevent the
109 optimizer from recognizing that the query matches an index.
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112 The following example command defines a GiST index operator class for
113 the data type _int4 (array of int4). See contrib/intarray/ for the com‐
114 plete example.
115 CREATE OPERATOR CLASS gist__int_ops
117 DEFAULT FOR TYPE _int4 USING gist AS
118 OPERATOR 3 &&,
119 OPERATOR 6 = RECHECK,
120 OPERATOR 7 @>,
121 OPERATOR 8 <@,
122 OPERATOR 20 @@ (_int4, query_int),
123 FUNCTION 1 g_int_consistent (internal, _int4, int4),
124 FUNCTION 2 g_int_union (bytea, internal),
125 FUNCTION 3 g_int_compress (internal),
126 FUNCTION 4 g_int_decompress (internal),
127 FUNCTION 5 g_int_penalty (internal, internal, internal),
128 FUNCTION 6 g_int_picksplit (internal, internal),
129 FUNCTION 7 g_int_same (_int4, _int4, internal);
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133 CREATE OPERATOR CLASS is a PostgreSQL extension. There is no CREATE
134 OPERATOR CLASS statement in the SQL standard.
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137 ALTER OPERATOR CLASS [alter_operator_class(7)], DROP OPERATOR CLASS
138 [drop_operator_class(l)]
139SQL - Language Statements 2008-06-08 CREATE OPERATOR CLASS()