Re: delete on cascade

--- Luca Ferrari <fluca1978(at)infinito(dot)it> wrote:

> 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.
> Luca

drop the constraint and re-declare it. (you can see the constraint
name by \dt skill from psql.)

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