Howe
Cc: [EMAIL PROTECTED]
Subject: Re: user defined table constraint
You need to use a UNIQUE index:
ALTER TABLE ADD UNIQUE user_id_primary (user_id, is_primary);
I can't find a specific section about UNIQUE indexes in the mysql
docs, but I'm sure it's there and I'm pret
Excuse me for top-posting but Outlook Express won't put revision bars in
front of your original remarks and I'm too lazy to type them all in myself
;-)
Anyway, if you define one of your columns, such as user_id as a primary key,
you can be sure that there will never be two rows with the same user_
That depends, can the user have more than 2 records? as in only 1 "yes"
record and 1 "no" record? If that were the case you could create a unique
index on (user_id, is_primary). However, I suspect that is not the case.
If I remember my M$ $QL correctly, User Constraints are evaluated during
INS