Provided by: postgresql-client-9.1_9.1.1-1_i386 bug

NAME

       CREATE_OPERATOR_CLASS - define a new operator class

SYNOPSIS

       CREATE OPERATOR CLASS name [ DEFAULT ] FOR TYPE data_type
         USING index_method [ FAMILY family_name ] AS
         {  OPERATOR strategy_number operator_name [ ( op_type, op_type ) ] [ FOR SEARCH | FOR ORDER BY sort_family_name ]
          | FUNCTION support_number [ ( op_type [ , op_type ] ) ] function_name ( argument_type [, ...] )
          | STORAGE storage_type
         } [, ... ]

DESCRIPTION

       CREATE OPERATOR CLASS creates a new operator class. An operator class
       defines how a particular data type can be used with an index. The
       operator class specifies that certain operators will fill particular
       roles or "strategies" for this data type and this index method. The
       operator class also specifies the support procedures to be used by the
       index method when the operator class is selected for an index column.
       All the operators and functions used by an operator class must be
       defined before the operator class can be created.

       If a schema name is given then the operator class is created in the
       specified schema. Otherwise it is created in the current schema. Two
       operator classes in the same schema can have the same name only if they
       are for different index methods.

       The user who defines an operator class becomes its owner. Presently,
       the creating user must be a superuser. (This restriction is made
       because an erroneous operator class definition could confuse or even
       crash the server.)

       CREATE OPERATOR CLASS does not presently check whether the operator
       class definition includes all the operators and functions required by
       the index method, nor whether the operators and functions form a
       self-consistent set. It is the user's responsibility to define a valid
       operator class.

       Related operator classes can be grouped into operator families. To add
       a new operator class to an existing family, specify the FAMILY option
       in CREATE OPERATOR CLASS. Without this option, the new class is placed
       into a family named the same as the new class (creating that family if
       it doesn't already exist).

       Refer to Section 35.14, "Interfacing Extensions To Indexes", in the
       documentation for further information.

PARAMETERS

       name
           The name of the operator class to be created. The name can be
           schema-qualified.

       DEFAULT
           If present, the operator class will become the default operator
           class for its data type. At most one operator class can be the
           default for a specific data type and index method.

       data_type
           The column data type that this operator class is for.

       index_method
           The name of the index method this operator class is for.

       family_name
           The name of the existing operator family to add this operator class
           to. If not specified, a family named the same as the operator class
           is used (creating it, if it doesn't already exist).

       strategy_number
           The index method's strategy number for an operator associated with
           the operator class.

       operator_name
           The name (optionally schema-qualified) of an operator associated
           with the operator class.

       op_type
           In an OPERATOR clause, the operand data type(s) of the operator, or
           NONE to signify a left-unary or right-unary operator. The operand
           data types can be omitted in the normal case where they are the
           same as the operator class's data type.

           In a FUNCTION clause, the operand data type(s) the function is
           intended to support, if different from the input data type(s) of
           the function (for B-tree and hash indexes) or the class's data type
           (for GIN and GiST indexes). These defaults are always correct, so
           there is no point in specifying op_type in a FUNCTION clause in
           CREATE OPERATOR CLASS, but the option is provided for consistency
           with the comparable syntax in ALTER OPERATOR FAMILY.

       sort_family_name
           The name (optionally schema-qualified) of an existing btree
           operator family that describes the sort ordering associated with an
           ordering operator.

           If neither FOR SEARCH nor FOR ORDER BY is specified, FOR SEARCH is
           the default.

       support_number
           The index method's support procedure number for a function
           associated with the operator class.

       function_name
           The name (optionally schema-qualified) of a function that is an
           index method support procedure for the operator class.

       argument_type
           The parameter data type(s) of the function.

       storage_type
           The data type actually stored in the index. Normally this is the
           same as the column data type, but some index methods (currently GIN
           and GiST) allow it to be different. The STORAGE clause must be
           omitted unless the index method allows a different type to be used.

       The OPERATOR, FUNCTION, and STORAGE clauses can appear in any order.

NOTES

       Because the index machinery does not check access permissions on
       functions before using them, including a function or operator in an
       operator class is tantamount to granting public execute permission on
       it. This is usually not an issue for the sorts of functions that are
       useful in an operator class.

       The operators should not be defined by SQL functions. A SQL function is
       likely to be inlined into the calling query, which will prevent the
       optimizer from recognizing that the query matches an index.

       Before PostgreSQL 8.4, the OPERATOR clause could include a RECHECK
       option. This is no longer supported because whether an index operator
       is "lossy" is now determined on-the-fly at run time. This allows
       efficient handling of cases where an operator might or might not be
       lossy.

EXAMPLES

       The following example command defines a GiST index operator class for
       the data type _int4 (array of int4). See the intarray module for the
       complete example.

           CREATE OPERATOR CLASS gist__int_ops
               DEFAULT FOR TYPE _int4 USING gist AS
                   OPERATOR        3       &&,
                   OPERATOR        6       = (anyarray, anyarray),
                   OPERATOR        7       @>,
                   OPERATOR        8       <@,
                   OPERATOR        20      @@ (_int4, query_int),
                   FUNCTION        1       g_int_consistent (internal, _int4, int, oid, internal),
                   FUNCTION        2       g_int_union (internal, internal),
                   FUNCTION        3       g_int_compress (internal),
                   FUNCTION        4       g_int_decompress (internal),
                   FUNCTION        5       g_int_penalty (internal, internal, internal),
                   FUNCTION        6       g_int_picksplit (internal, internal),
                   FUNCTION        7       g_int_same (_int4, _int4, internal);

COMPATIBILITY

       CREATE OPERATOR CLASS is a PostgreSQL extension. There is no CREATE
       OPERATOR CLASS statement in the SQL standard.

SEE ALSO

       ALTER OPERATOR CLASS (ALTER_OPERATOR_CLASS(7)), DROP OPERATOR CLASS
       (DROP_OPERATOR_CLASS(7)), CREATE OPERATOR FAMILY
       (CREATE_OPERATOR_FAMILY(7)), ALTER OPERATOR FAMILY
       (ALTER_OPERATOR_FAMILY(7))