From: Pedro Igor <pedroigor@aip.com.br>
To: pgsql-sql@postgresql.org
Subject: Query
Date: Fri, 3 Jan 2003 11:46:27 -0200
Message-ID: <000d01c2b32e$8529eca0$0b00010a@aip.com.br> (raw)
Regards .....
I hope someone can help me in this query.
Have a field in a table that needs to check if another table has the value that is being inserted.
Ex:
table A
- id int constraint pkey_id primary key,
table B
- id int constraint fkey_A_B references A,
Here comes my doubt:
table C
- id int constraint fkey_A_C references A check (if exists B.id = C.id)
How can i build this expression so, when I insert a tupple in table C the field will check in the table A(ok, because is a foreign key) and also in table B ....
I have tried : check (select count(b.id) from B b where b.id = id) <> 0) .... but doesn´t work ......
I can use trigger here, but i don´t know if is the best solution .....
Thanks,
Pedro Igor
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