How do I do this (business logic) on Sql Server? Restriction?

Question

I want to add some type of business logic constraint to the table, but not sure how / where.

I have a table with the following fields.

• IDENTIFICATION ID INTEGER
• HubId INTEGER
• CategoryId INTEGER
• IsFeatured BIT
• Foo NVARCHAR (200)

and etc.

So I want you to have only one great thing, for hubId + categoryId.

eg.
1, 1, 1, 1, 'blah'  -- Ok.
2, 1, 2, 1, 'more blah' -- Also Ok
3, 1, 1, 1, 'aaa' -- constraint error
4, 1, 1, 0, 'asdasdad' -- Ok.
5, 1, 1, 0, 'bbbb' -- Ok.

etc.

therefore the third row to be inserted will fail, because this studio AND category already has an excellent thing.

Is it possible?

Answer 1

. - - :

:

• IsFeatured = 1 HubId, CategoryId, IsFeatured
• , SQL Server 2008 ( )

3,

PS: ID?

: UNIQUE CHECK

Edit:

,

CREATE UNIQUE INDEX IX_Foo ON Mytable (HubId, CategoryId) WHERE IsFeatured = 1

, (HubId, CategoryId) , IsFeatured = 1