Defensive Database Programming - Red Gate Software

Chapter 3: Surviving Changes to Database ObjectsUsing @@ROWCOUNT to verify assumptionsAlternatively, instead of documenting our assumption as a unit test, we can have ourstored procedure detect how many rows it modified, and roll back if it updated morethan one row, as shown in Listing 3-9.ALTER PROCEDURE dbo.SetCustomerStatus@PhoneNumber VARCHAR(50) ,@Status VARCHAR(50)ASBEGIN ;BEGIN TRANSACTION ;UPDATE dbo.CustomersSET Status = @StatusWHERE PhoneNumber = @PhoneNumber ;IF @@ROWCOUNT > 1BEGIN ;ROLLBACK ;RAISERROR('More than one row updated',16, 1) ;END ;ELSEBEGIN ;COMMIT ;END ;END ;Listing 3-9: A stored procedure that will not modify more than one row.To see it in action, run Listing 3-10; the stored procedure raises an error and does notmodify the data.85