Re: Do I need a PK on a join table?
Date: 15 Feb 2006 04:56:14 -0800
Message-ID: <1140008174.632670.286400_at_g47g2000cwa.googlegroups.com>
>> SQL and DB2 confound the issue by mixing physical structures (indexes)
>> with purely logical integrity constraints (uniqueness/keys), by allowing
>> the abominable NULL,
>I don't know where there is anything "mixed" and how NULL would fit into
>this statement. Could you possibly explain how you mean that?
I think that this is crystal clear. Indices are physical artifacts and keys are logical level integrity constraints. Nulls are an abomination that interfer with many things including integrity constraints.
>> If you have a strong argument for wanting no index, declare a uniqueness
>> constraint.
>Which will be enforced by a unique index...
Which could be implemented with the help of a unique index.
Regards
Alfredo
Received on Wed Feb 15 2006 - 13:56:14 CET