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ALTER OPERATOR FAMILY() SQL Commands ALTER OPERATOR FAMILY()
NAME
ALTER OPERATOR FAMILY - change the definition of an operator family
SYNOPSIS
ALTER OPERATOR FAMILY name USING index_method ADD
{ OPERATOR strategy_number operator_name ( op_type, op_type ) [ RECHECK ]
| FUNCTION support_number [ ( op_type [ , op_type ] ) ] funcname ( argument_type [, ...] )
} [, ... ]
ALTER OPERATOR FAMILY name USING index_method DROP
{ OPERATOR strategy_number ( op_type [ , op_type ] )
| FUNCTION support_number ( op_type [ , op_type ] )
} [, ... ]
ALTER OPERATOR FAMILY name USING index_method RENAME TO newname
ALTER OPERATOR FAMILY name USING index_method OWNER TO newowner
DESCRIPTION
ALTER OPERATOR FAMILY changes the definition of an operator family. You can add
operators and support functions to the family, remove them from the family, or
change the family's name or owner.
When operators and support functions are added to a family with ALTER OPERATOR FAM-
ILY, they are not part of any specific operator class within the family, but are
just ''loose'' within the family. This indicates that these operators and functions
are compatible with the family's semantics, but are not required for correct func-
tioning of any specific index. (Operators and functions that are so required should
be declared as part of an operator class, instead; see CREATE OPERATOR CLASS [cre-
ate_operator_class(7)].) PostgreSQL will allow loose members of a family to be
dropped from the family at any time, but members of an operator class cannot be
dropped without dropping the whole class and any indexes that depend on it. Typi-
cally, single-data-type operators and functions are part of operator classes
because they are needed to support an index on that specific data type, while
cross-data-type operators and functions are made loose members of the family.
You must be a superuser to use ALTER OPERATOR FAMILY. (This restriction is made
because an erroneous operator family definition could confuse or even crash the
server.)
ALTER OPERATOR FAMILY does not presently check whether the operator family defini-
tion 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 family.
Refer to in the documentation for further information.
PARAMETERS
name The name (optionally schema-qualified) of an existing operator family.
index_method
The name of the index method this operator family is for.
strategy_number
The index method's strategy number for an operator associated with the oper-
ator family.
operator_name
The name (optionally schema-qualified) of an operator associated with the
operator family.
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. Unlike the comparable syntax
in CREATE OPERATOR CLASS, the operand data types must always be specified.
In an ADD 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 it is not necessary to specify op_type since the func-
tion's input data type(s) are always the correct ones to use. For GIN and
GiST indexes it is necessary to specify the input data type the function is
to be used with.
In a DROP FUNCTION clause, the operand data type(s) the function is intended
to support must be specified.
RECHECK
If present, the index is ''lossy'' for this operator, and so the rows
retrieved using the index must be rechecked to verify that they actually
satisfy the qualification clause involving this operator.
support_number
The index method's support procedure number for a function associated with
the operator family.
funcname
The name (optionally schema-qualified) of a function that is an index method
support procedure for the operator family.
argument_types
The parameter data type(s) of the function.
newname
The new name of the operator family.
newowner
The new owner of the operator family.
The OPERATOR and FUNCTION clauses can appear in any order.
NOTES
Notice that the DROP syntax only specifies the ''slot'' in the operator family, by
strategy or support number and input data type(s). The name of the operator or
function occupying the slot is not mentioned. Also, for DROP FUNCTION the type(s)
to specify are the input data type(s) the function is intended to support; for GIN
and GiST indexes this might have nothing to do with the actual input argument types
of the function.
Because the index machinery does not check access permissions on functions before
using them, including a function or operator in an operator family 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 family.
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 recogniz-
ing that the query matches an index.
EXAMPLES
The following example command adds cross-data-type operators and support functions
to an operator family that already contains B-tree operator classes for data types
int4 and int2.
ALTER OPERATOR FAMILY integer_ops USING btree ADD
-- int4 vs int2
OPERATOR 1 < (int4, int2) ,
OPERATOR 2 <= (int4, int2) ,
OPERATOR 3 = (int4, int2) ,
OPERATOR 4 >= (int4, int2) ,
OPERATOR 5 > (int4, int2) ,
FUNCTION 1 btint42cmp(int4, int2) ,
-- int2 vs int4
OPERATOR 1 < (int2, int4) ,
OPERATOR 2 <= (int2, int4) ,
OPERATOR 3 = (int2, int4) ,
OPERATOR 4 >= (int2, int4) ,
OPERATOR 5 > (int2, int4) ,
FUNCTION 1 btint24cmp(int2, int4) ;
To remove these entries again:
ALTER OPERATOR FAMILY integer_ops USING btree DROP
-- int4 vs int2
OPERATOR 1 (int4, int2) ,
OPERATOR 2 (int4, int2) ,
OPERATOR 3 (int4, int2) ,
OPERATOR 4 (int4, int2) ,
OPERATOR 5 (int4, int2) ,
FUNCTION 1 (int4, int2) ,
-- int2 vs int4
OPERATOR 1 (int2, int4) ,
OPERATOR 2 (int2, int4) ,
OPERATOR 3 (int2, int4) ,
OPERATOR 4 (int2, int4) ,
OPERATOR 5 (int2, int4) ,
FUNCTION 1 (int2, int4) ;
COMPATIBILITY
There is no ALTER OPERATOR FAMILY statement in the SQL standard.
SEE ALSO
CREATE OPERATOR FAMILY [create_operator_family(7)], DROP OPERATOR FAMILY
[drop_operator_family(l)], CREATE OPERATOR CLASS [create_operator_class(l)], ALTER
OPERATOR CLASS [alter_operator_class(l)], DROP OPERATOR CLASS [drop_opera-
tor_class(l)]
SQL - Language Statements 2009-03-12 ALTER OPERATOR FAMILY()
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On Apache/2.2.3 (Red Hat)
Under GNU General Public License
2009-12-23 21:04 @127.0.0.1 CrawledBy CCBot/1.0 (+http://www.commoncrawl.org/bot.html)