Provided by: postgresql-client-8.0_8.0.7-2build1_i386 bug


       SET  CONSTRAINTS  -  set  constraint  checking  modes  for  the current


       SET CONSTRAINTS { ALL | name [, ...] } { DEFERRED | IMMEDIATE }


       SET CONSTRAINTS sets the behavior of  constraint  checking  within  the
       current  transaction.  IMMEDIATE  constraints are checked at the end of
       each statement. DEFERRED constraints are not checked until  transaction
       commit. Each constraint has its own IMMEDIATE or DEFERRED mode.

       Upon  creation,  a  constraint  is  given one of three characteristics:
       DEFERRABLE.  The third class is always IMMEDIATE and is not affected by
       the  SET  CONSTRAINTS  command.  The  first  two  classes  start  every
       transaction  in  the  indicated mode, but their behavior can be changed
       within a transaction by SET CONSTRAINTS.

       SET CONSTRAINTS with a list of constraint names  changes  the  mode  of
       just  those  constraints  (which  must all be deferrable). If there are
       multiple constraints matching any given name, all  are  affected.   SET
       CONSTRAINTS ALL changes the mode of all deferrable constraints.

       When  SET CONSTRAINTS changes the mode of a constraint from DEFERRED to
       IMMEDIATE, the new mode takes  effect  retroactively:  any  outstanding
       data  modifications  that  would  have  been  checked at the end of the
       transaction are  instead  checked  during  the  execution  of  the  SET
       CONSTRAINTS  command.   If  any  such  constraint  is violated, the SET
       CONSTRAINTS fails (and does not change the constraint mode). Thus,  SET
       CONSTRAINTS  can be used to force checking of constraints to occur at a
       specific point in a transaction.

       Currently, only foreign key constraints are affected by  this  setting.
       Check and unique constraints are always effectively not deferrable.


       This command only alters the behavior of constraints within the current
       transaction. Thus, if you execute this command outside of a transaction
       block (BEGIN/COMMIT pair), it will not appear to have any effect.


       This  command  complies  with the behavior defined in the SQL standard,
       except for the limitation that,  in  PostgreSQL,  it  only  applies  to
       foreign-key constraints.

       The   SQL   standard  says  that  constraint  names  appearing  in  SET
       CONSTRAINTS can be schema-qualified.  This  is  not  yet  supported  by
       PostgreSQL: the names must be unqualified, and all constraints matching
       the command will be affected no matter which schema they are in.