1 foreign key to 2 different tables?
От | Ryan Riehle |
---|---|
Тема | 1 foreign key to 2 different tables? |
Дата | |
Msg-id | 000001c42fad$5350abe0$0302a8c0@buildways обсуждение исходный текст |
Ответ на | Re: One or Both Foregin Keys (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: 1 foreign key to 2 different tables?
Re: 1 foreign key to 2 different tables? |
Список | pgsql-general |
Hi, I have a key structure like so: a c b +----------+ +---------+ +----------+ | PriKey1 |--->| ForKey |<---| PriKey2 | | | | Flag | | | +----------+ +---------+ +----------+ ...where c.ForKey is a value from PriKey1 OR PriKey2, which are different values. All fields have the same data type; a.PriKey1 and b.PriKey2 are sequences. How does one enfore referential integrity in this structure so that c.ForKey references a.PriKeya when Flag is True or references b.PriKey2 when Flag is False? Looked pretty hard through the lists and on Google last night with no luck :( -Ryan Riehle http://www.buildways.com KEYWORDS: one foreign key, multiple primary keys, multiple tables, generalization, superclass, subclass, constraint
В списке pgsql-general по дате отправления: