In your example can you Make cx.r a foreign key on another table (say real) so that a valid instance of cx must have a value for r that exists in real? I guess you could make r an enum but that wouldn't readily allow you to modify the allowable values for r. A domain and/or check constraint for r would be another option as well. David J. On May 6, 2011, at 10:32, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > Vincent De Groote <vdg.encelade@xxxxxxxxx> writes: >> I have a composite type with 2 fields. I would like to check that one >> of these fields exists in another table. >> Foreign keys on a composite field does not seem to be supported. > > Works for me, in 8.4 and up. Whether it's a good idea is a different > issue (I think it'll be pretty inefficient, compared to a multicolumn > primary/foreign key on native datatypes), but it works. > > regression=# create type cx as (r float8, i float8); > CREATE TYPE > regression=# create table p (id cx primary key); > NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "p_pkey" for table "p" > CREATE TABLE > regression=# create table s (c cx references p); > CREATE TABLE > > regards, tom lane > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
