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       CREATE OPERATOR CLASS - define a new operator class


         USING index_method [ FAMILY family_name ] AS
         {  OPERATOR strategy_number operator_name [ ( op_type, op_type ) ]
          | FUNCTION support_number [ ( op_type [ , op_type ] ) ] funcname ( argument_type [, ...] )
          | STORAGE storage_type
         } [, ... ]


       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 in the documentation for further information.


       name   The name of the operator class to be created. The  name  can  be

              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.

              The column data type that this operator class is for.

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

              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

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

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

              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.

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

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

              The parameter data type(s) of the function.

              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

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


       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  runtime.  This  allows
       efficient  handling  of  cases  where an operator might or might not be


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


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


       ALTER  OPERATOR  CLASS  [alter_operator_class(7)],  DROP OPERATOR CLASS
       [drop_operator_class(7)],        CREATE         OPERATOR         FAMILY
       [create_operator_family(7)],        ALTER        OPERATOR        FAMILY