I must be missing something Dimity.

Why is class_pk in the parts table a primary key?

I'd expect the part number or something like to be the PK in that table.


>Hi,
>
>I must be missing something simple. When I try to set the foreign key constraint, it fails. Here is the description:
>1. I added new table PART_CLASS with primary column CLASS_PK (Int), Identity.
>2. I added to PARTS table a column CLASS_PK (int), default 0
>
>I want to be sure that when/if the row/record in PART_CLASS is deleted, all referenced rows in PARTS set the value in columnd CLASS_PK to default (0).
>
>I think the constraint, when I set it up in SSMS, fails because table PARTS has many records and all of them have value 0 in the column CLASS_PK. But table PART_CLASS has no records. So SQL Server does not find a record in PART_CLASS of CLASS_PK value 0.
>
>How do you deal with this? TIA.