Re: 7.4 - TODO : alter table drop foreign key

On Thu, 5 Dec 2002, Dan Langille wrote:

> On 5 Dec 2002 at 8:20, Stephan Szabo wrote:
>
> >
> > On Thu, 5 Dec 2002, Dan Langille wrote:
> >
> > > We support "alter table add foreign key". How about supporting
> > > "alter table drop foreign key"?
> > >
> > > - he said as he went to drop a foreign key
> >
> > It seems to work for me on my 7.3b2 system with
> > alter table <table> drop constraint <constraint name>;
>
> Premature send.. sorry
>
> How was that FK added? How did you determine the constraint name?

alter table <table> add constraint <name> foreign key ...

> How would you do that if the FK was added with the following syntax?
>
> alter table <table>
> add foreign key (<column>)
> references <othertable> (<othercolumn>)
> on update cascade on delete cascade;

IIRC, the constraint will get an automatic name of the form
$<n> in such cases. I believe if you do a \d on the table,
it gives the name in the constraint definitions (on one of mine
i get:

Foreign Key constraints: $1 FOREIGN KEY (a) REFERENCES qqq(a) ON UPDATE
CASCADE ON DELETE NO ACTION

Where $1 is the name of the constraint.