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foreign key with where clause - Mailing list pgsql-general

From	Mark Lybarger
Subject	foreign key with where clause
Date	August 18, 2016 20:10:41
Msg-id	CAKM-gm+-tykGb99J8fKrwv+ZeawmYxONPS+X9ULJ=ef-_3avhA@mail.gmail.com Whole thread Raw
Responses	Re: foreign key with where clause (Branden Visser <mrvisser@gmail.com>) Re: foreign key with where clause (Manuel Gómez <targen@gmail.com>)
List	pgsql-general

I have two tables that i want to link with a FK where the child table record is "active".

some googling shows that i could use a function and a check constraint on the function, but that only works for inserts, not updates on table b.

create table a (int id, text name);

create table b (int id, boolean active);

alter table a add column b_id integer;

-- how to do this?

alter table a add foreign key (b_id) references b(id) where b.active == true

help :).

From: Francisco Olarte
Date: 18 August 2016, 19:42:06
Subject: Re: Sequential vs. random values - number of pages in B-tree

From: Branden Visser
Date: 18 August 2016, 20:19:10
Subject: Re: foreign key with where clause