does any one have instances where "on delete cascade" is written in, but when trying to delete the record in parent table, it still gives errors stating the key is still being referenced?

Did you try to implement it with triggers?

that's precisely the problem...
in my understanding the "on delete cascade" should serve the function of a delete trigger.

i am sure it would work if i write a delete trigger, but i want to know why would the "on delete cascade" not work..

example:

create table test
(testid serial primary key)

create table test2
(testid integer,
foreign key (testid)
references test
on delete cascade)

if i delete a record in test(which is referenced in test2)
the error message would state that the key is still being referenced and could not be deleted

but isn't it what "on delete cascade" is supposed to handle??