> Hi all,
> I guess this is an already asked question, but I didn't found an answer, so
> apologize me. Imagine I've got two tables:
> skill(id,description) // primary key => id
> family(id,description) // primary key => id
> and I want to associate skills to families:
> ass_sf(id_skill,id_family) // appropriate foreign keys
>
> Tables are already created and the database is running. Now I'd like to
> implement a delete cascade, thus when I delete a skill also its association
> with the family must be deleted. I gues I should have declared the skill
> table as follows:
> CREATE TABLE skill
> (
> id varchar(20) on delete cascade,
> description varchar(50),
> primary key(id)
> );
>
> right? The problem is: how can I alter the table to add the column constraint
> now, without redeclaring the table?
> Thanks very much for helping me.
This link has one line that is very similar to what you want to do. You will probably have to
start a transaction, drop the foriegn key contraint and then add a new foriegn key contraint with
the on drop cascade .
http://archives.postgresql.org/pgsql-general/2006-10/msg00467.php
Regards,
Richard Broersma Jr.