cascading deletes causing multiple cascade paths

Question

I am using SQlServer 2008, and an extract of some datatables is displayed below:

Users

Id (PK)

UserItems

UserId (PK) ItemId (PK) - (Compo

Answer 1

"UserItems.ItemId -> UserItemVotes.UserId"

This one seems extremely suspect.

Answer 2

The approved answer is not a good answer. The scenario described is not bad design, nor is it "risky" to rely on the database to do its job.

The original question describes a perfectly valid scenario, and the design is well thought-out. Clearly, deleting a user should delete both the user's items (and any votes on them), and delete the user's votes on any item (even items belonging to other users). It is reasonable to ask the database to perform this cascading delete when the user record is deleted.

The problem is that SQL Server can't handle it. Its implementation of cascading deletes is deficient.

Answer 3

I would lead toward bad design. While most DBMSs can manage cascading deletes, it is risky to use this built in functionality. Your scenario is a perfect example of why these types of things are often managed in application code. There you can determine exactly what needs to be deleted and in what order.