Re: 7.4 - TODO : alter table drop foreign key

On 5 Dec 2002 at 8:44, Stephan Szabo wrote:

> 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.

Thanks.  In my 7.2.3 database, the table in question has:

Primary key: watch_list_staging_pkey
Check constraints: "watch_list_stag_from_watch_list" 
((from_watch_list = 't'::bool) OR (from_watch_list = 'f'::bool))                  "watch_list_stagin_from_pkg_info"
((from_pkg_info
 
= 't'::bool) OR (from_pkg_info = 'f'::bool))
Triggers: RI_ConstraintTrigger_4278482,         RI_ConstraintTrigger_4278488

No mention of FK constraints.
-- 
Dan Langille : http://www.langille.org/