Re: Foreign Key with Constant
От | Gregory Wood |
---|---|
Тема | Re: Foreign Key with Constant |
Дата | |
Msg-id | 074101c2d9dd$dd7e58c0$4f89ffcc@eng3 обсуждение исходный текст |
Ответ на | Re: Foreign Key with Constant (Stephan Szabo <sszabo@megazone23.bigpanda.com>) |
Список | pgsql-general |
> > Is it possible to create a foreign key that uses a constant for one of the > > fields. In other words, I want to foreign key one value into another table, > > Not directly no. *nod* I figured as much. > > I'd rather do this without adding a 'constant' column, or messing too > > extensively without triggers, but I fear that one of these might be > > necessary. > > Unfortunately I think you'll need to do either the constant column or > triggers (the SQL mandated way of solving this is probably check > constraints with subselects but we don't support that) If you only > care about insert time on the fk table and not about moidfications to the > pk table you can get away with a simple function that you use in a check > constraint I think. Actually, I think that sounds like the best solution. It will be a relatively infrequently used table and I'd like to keep things simple (not cluttering up the design with extra columns and triggers). Thanks! Greg
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