On Sun, Mar 19, 2017 at 8:53 PM, Patrick B <patrickbake...@gmail.com> wrote:
> > > 2017-03-20 13:27 GMT+13:00 Melvin Davidson <melvin6...@gmail.com>: > >> >> >> On Sun, Mar 19, 2017 at 8:16 PM, Patrick B <patrickbake...@gmail.com> >> wrote: >> >>> Hi guys, >>> >>> I've got a column 'type_note' on a new table that it's being designed: >>> >>> type_note varchar(32) NOT NULL; >>> >>> On that column, there will be three different data: >>> >>> 1. yes >>> 2. no >>> 3. maybe >>> >>> I wanna create a FK but just when the data on that column is = maybe. >>> >>> How can I do that? Thanks! >>> >>> >> Why just "maybe"? Since there can only be three valid answers, why not FK >> for all three? >> >> -- >> > > > > I was able to get what I needed this way: > > create table testing_fk_conditional_1 ( >> id serial NOT NULL PRIMARY KEY, >> account_id bigint, >> user_id bigint, >> type_note integer NOT NULL, >> CHECK (type_note = 100 AND user_id IS NOT NULL OR type_note = 200 AND >> account_id IS NOT NULL) >> ); > > That is not what you asked for originally, but as long as you are happy. -- *Melvin Davidson* I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.
