Re: [GENERAL] Foreign keys/unique values and views
On Thu, 22 Mar 2001, Richard Huxton wrote: I have to admit I've never tried referencing a view with a foreign key. I don't know if it's possible and I have to admit the idea makes me uncomfortable. Can't give a good reason why, but I'd apply constraints at the table level. if one can reference a table with a foreign key it makes possible to reference inheritance hierarchies. If I create a view from the parent with CREATE VIEW name SELECT * FROM parent; (in v.7.1) it should contain the entries from the children as well. Now if I could reference this view I could simulate referencing parent and child tables easily. What I have in mind is a hierarchy of persons all inheriting from a table called person. Different kinds of persons have different attributes but all have an id and name. What I want is that other tables could reference these persons easily. - Einar Karttunen ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html
Re: [GENERAL] Foreign keys/unique values and views
On Thu, Mar 22, 2001 at 06:33:16PM -0500, Jan Wieck wrote: Einar Karttunen wrote: How do you put a UNIQUE constraint on the entire inheritance hierarchie? Easy. You make a unique index that covers an entire inheritance hierarchy. If lots of table inherit a field "id" from a single table the you can put a unique index on that field. All you need then is an index whose keys reference not tuple IDs but (table ID, tuple ID) pairs. Wow. I'm just thinking of how vacuum would deal with this. Probably not very well. But it would give inheritance hierarchies very efficient lookups rather than the implicit unioning done currently. Martijn ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
