CREATE OPERATOR 
CLASS(7)					   SQL Commands 					  CREATE OPERATOR CLASS(7)

NAME

       CREATE OPERATOR CLASS - define a new operator class for indexes

SYNOPSIS

       CREATE OPERATOR CLASS name [ DEFAULT ] FOR TYPE data_type USING access_method AS
	 {  OPERATOR strategy_number operator_id [ ( type, type ) ] [ RECHECK ]
	  | FUNCTION support_number func_name ( parameter_types )
	  | STORAGE storage_type
	 } [, ... ]

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

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

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

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

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

       operator_id
	      The identifier (optionally schema-qualified) of an operator associated with the operator class.

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

       RECHECK
	      If  present,  the index is ``lossy'' for this operator, and so the tuples retrieved using the index must be rechecked to verify that
	      they actually satisfy the qualification clause involving this operator.

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

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

       parameter_types
	      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 access  methods  (only
	      GIST at this writing) allow it to be different. The STORAGE clause must be omitted unless the index access method allows a different
	      type to be used.

   OUTPUTS
       CREATE OPERATOR CLASS
	      Message returned if the operator class is successfully created.

DESCRIPTION

       CREATE OPERATOR CLASS defines a new operator class, name.

       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 access method. The operator class also specifies the support procedures
       to be used by the index access 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 is 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 (the
       one at the front of the search path; see CURRENT_SCHEMA()).  Two operator classes in the same schema can have the same name  only  if  they
       are for different index access 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 class definition includes all the operators and functions required by the  index
       access method. It is the user's responsibility to define a valid operator class.

       Refer to the chapter on interfacing extensions to indexes in the PostgreSQL Programmer's Guide for further information.

   NOTES
       Refer to DROP OPERATOR CLASS [drop_operator_class(7)] to delete user-defined operator classes from a database.

USAGE

       The  following  example command defines a GiST index operator class for data type _int4 (array of int4). See contrib/intarray/ for the com-
       plete example.

       CREATE OPERATOR CLASS gist__int_ops
	   DEFAULT FOR TYPE _int4 USING gist AS
	       OPERATOR        3       &&,
	       OPERATOR        6       =       RECHECK,
	       OPERATOR        7       @,
	       OPERATOR        8       ~,
	       OPERATOR        20      @@ (_int4, query_int),
	       FUNCTION        1       g_int_consistent (internal, _int4, int4),
	       FUNCTION        2       g_int_union (bytea, 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);

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

COMPATIBILITY

   SQL92
       CREATE OPERATOR CLASS is a PostgreSQL extension.  There is no CREATE OPERATOR CLASS statement in SQL92.

SQL - Language Statements					    2002-11-22						  CREATE OPERATOR CLASS(7)