REFERENCES

Hi,

i have a simple problem and wont request assistance fro m this list.
i have to tables

foo:
id int8 UNIQUE

bar:
id int8 UNIQUE
foo_id int8

Now i wont foo_id to be a id which exists in the foo, this could be done
with foo_id REFERENCES foo (id).
But what should i do if i want foo_id to be a id existing in foo or to
be zero(0).
I have created a view as "select id from foo UNION select 0" and tried
to REFERENCE against this view, but that
doesnt work.
Can this problem be solved by a somebody ????

Thanks

--
Andre Schubert EMail: Andre(dot)Schubert(at)km3(dot)de
Tel: 03774 6625-78
km3 teledienst GmbH Fax: 03774 6625-79