"Luiz K. Matsumura" <luiz@planit.com.br> writes:
> Need a Help. Can a check constraint be deferred until the end of a
> transaction ?
Nope, sorry.
If you're desperate to have such functionality you could check the
condition in a "constraint trigger".
http://www.postgresql.org/docs/8.3/static/sql-createconstraint.html
regards, tom lane