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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 FAMILY,
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 functioning 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 [create_operator_class(7)].) Post-
greSQL 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. Typically, 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 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 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 operator
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 OPERA-
TOR 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 function's input data
type(s) are always the correct ones to use. For GIN and GiST indexes it is neces-
sary 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 qualifi-
cation 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 sup-
port 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 strat-
egy or support number and input data type(s). The name of the operator or function occupy-
ing 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 recognizing 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_opera-
tor_family(l)], CREATE OPERATOR CLASS [create_operator_class(l)], ALTER OPERATOR CLASS
[alter_operator_class(l)], DROP OPERATOR CLASS [drop_operator_class(l)]
SQL - Language Statements 2011-09-22 ALTER OPERATOR FAMILY()
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On Apache
Under GNU General Public License
2012-05-25 17:19 @38.107.179.237 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)