Re: ALTER TABLE table DROP CONSTRAINT problem

Lewis Bergman <lbergman(at)[nospam]abi(dot)tconline(dot)net> writes:
> I am trying to drop a constraint that was set up by this SQL
> ALTER TABLE customer_main ADD CONSTRAINT cust_main_agent
> FOREIGN KEY ( agent )
> REFERENCES customer_main ( id )
> NOT DEFERRABLE;

> So I do this:
> ALTER TABLE customer_main DROP CONSTRAINT cust_main_agent RESTRICT;
> And get this error:
> ERROR: ALTER TABLE / DROP CONSTRAINT: cust_main_agent does not exist

AFAIK, the current implementation of DROP CONSTRAINT only supports
dropping CHECK constraints; it gives you that error because it doesn't
find anything about cust_main_agent in the check-constraint table.

You can manually drop a foreign-key constraint by dropping the three or
so triggers that implement it. I forget the details but they're in the
list archives.

There will probably be a cleaner way to do it in a release or two...

regards, tom lane