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CREATE CONSTRAINT TRIGGER(7)                   PostgreSQL 9.0.23 Documentation


NAME

       CREATE_CONSTRAINT_TRIGGER - define a new constraint trigger


SYNOPSIS

       CREATE CONSTRAINT TRIGGER name
           AFTER event [ OR ... ]
           ON table_name
           [ FROM referenced_table_name ]
           { NOT DEFERRABLE | [ DEFERRABLE ] { INITIALLY IMMEDIATE | INITIALLY DEFERRED } }
           FOR EACH ROW
           [ WHEN ( condition ) ]
           EXECUTE PROCEDURE function_name ( arguments )


DESCRIPTION

       CREATE CONSTRAINT TRIGGER creates a constraint trigger. This is the
       same as a regular trigger except that the timing of the trigger firing
       can be adjusted using SET CONSTRAINTS (SET_CONSTRAINTS(7)). Constraint
       triggers must be AFTER ROW triggers. They can be fired either at the
       end of the statement causing the triggering event, or at the end of the
       containing transaction; in the latter case they are said to be
       deferred. A pending deferred-trigger firing can also be forced to
       happen immediately by using SET CONSTRAINTS.


PARAMETERS

       name
           The name of the constraint trigger. This is also the name to use
           when modifying the trigger's behavior using SET CONSTRAINTS. The
           name cannot be schema-qualified -- the trigger inherits the schema
           of its table.

       event
           One of INSERT, UPDATE, or DELETE; this specifies the event that
           will fire the trigger. Multiple events can be specified using OR.

       table_name
           The (possibly schema-qualified) name of the table in which the
           triggering events occur.

       referenced_table_name
           The (possibly schema-qualified) name of another table referenced by
           the constraint. This option is used for foreign-key constraints and
           is not recommended for general use.

       DEFERRABLE, NOT DEFERRABLE, INITIALLY IMMEDIATE, INITIALLY DEFERRED
           The default timing of the trigger. See the CREATE TABLE
           (CREATE_TABLE(7)) documentation for details of these constraint
           options.

       condition
           A Boolean expression that determines whether the trigger function
           will actually be executed. This acts the same as in CREATE TRIGGER
           (CREATE_TRIGGER(7)). Note in particular that evaluation of the WHEN
           condition is not deferred, but occurs immediately after the row
           update operation is performed. If the condition does not evaluate
           to true then the trigger is not queued for deferred execution.

       function_name
           The function to call when the trigger is fired. See CREATE TRIGGER
           (CREATE_TRIGGER(7)) for details.

       arguments
           Optional argument strings to pass to the trigger function. See
           CREATE TRIGGER (CREATE_TRIGGER(7)) for details.


COMPATIBILITY

       CREATE CONSTRAINT TRIGGER is a PostgreSQL extension of the SQL
       standard.


SEE ALSO

       CREATE TRIGGER (CREATE_TRIGGER(7)), DROP TRIGGER (DROP_TRIGGER(7)), SET
       CONSTRAINTS (SET_CONSTRAINTS(7))

PostgreSQL 9.0.23                 2015-10-05      CREATE CONSTRAINT TRIGGER(7)

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