Re: Referencing multiple primary keys from a single table.
От | Bruno Wolff III |
---|---|
Тема | Re: Referencing multiple primary keys from a single table. |
Дата | |
Msg-id | 20030922223354.GA1331@wolff.to обсуждение исходный текст |
Ответ на | Referencing multiple primary keys from a single table. (Daniel Staal <DStaal@usa.net>) |
Список | pgsql-novice |
On Mon, Sep 22, 2003 at 16:34:11 -0500, Daniel Staal <DStaal@usa.net> wrote: > > What is the best way to reference (use as foreign key) a table with > multiple primary keys? > > Here's what I have: > Table1: > field1 > field2 > field3 > ... > primary key (field1, field2, field3) > > Then I have another table that needs to reference Table1 with a > foreign key. What I really want to do is: > Table2: > field1 Primary key > field2 references table1 > ... > > But that doesn't work. I haven't yet tried the option of giving > Table2 all three fields of Table1, partly because I'm not really sure > how to write that... (I did try linking it to the implicit field > generated when I created Table1. Didn't work.) The option I'm sure > would work is shoving all three key fields of Table1 into one field, > but that's a bit messy with the data. (Though it is doable.) If table2 looked like this field1 Primary Key field2 - field4 correspond to field1 - field3 of table 1 then you want to use a foreign key constraint after the column declarations. Something like: foreign key (field2, field3, field4) references table1
В списке pgsql-novice по дате отправления: