Re: DDL problems

The PRIMARY KEY constraint already incorporates NOT NULL and UNIQUE, so they do not need to exist as explicit constraints.

I am not aware of a way to create a multi-column foreign key.

Gennady wrote in message <36fa8c9e$0$10007_at_fountain.mindlink.net>...
>Hello,
>I’ve got problems:
>1. When I created a table’s primary key this constraint does not implicitly
>creates NOT NULL and UNIQUE constraints on the table.
>2. I can not create a foreign key on composite primary key. The only way is
>to split composite key on single field constraints, for example, instead
of:
>Constraint FK_LbrGroup_LSizes foreign key(LGroups,LbrGroup) references
>LumberGroups(LGroups,LbrGroup)
>
>I need create:
>Constraint FK_LGroups_LSizes foreign key(LGroups) references
>LumberGroups(LGroups),
>Constraint FK_LbrGroup_LSizes foreign key(LbrGroup) references
>LumberGroups(LbrGroup)
>
>Could you explain me the reasons ?
>Thank you,
>Gennady
>
>
>
Received on Thu Mar 25 1999 - 13:31:13 CST