"Fayza Sultan" <fayza(dot)sultan(at)gmail(dot)com> writes:
> CREATE TABLE parent (
> monthdate date NOT NULL,
> id int4 NOT NULL,
> CONSTRAINT parent_idx PRIMARY KEY (monthdate,id )
> );
> CREATE TABLE child1
> (
> CONSTRAINT child1_idx PRIMARY KEY (monthdate,id),
> CONSTRAINT child1_chk CHECK (monthdate >= '2006-01-01 00:00:00'::timestamp
> without time zone AND monthdate < '2006-02-01 00:00:00'::timestamp without
> time zone)
monthdate is date, not timestamp. See the caveat in the documentation
about avoiding cross-type comparisons when formulating constraints for
constraint exclusion to use.
regards, tom lane