"May cause cycles or multiple cascade paths" Error with only Two Tables

Hi,I have two tables called a and b. a has one row called aId where aId is the PK. b has bId, aId_1 and aId_2 where bId is the PK and aId_1 and aId_2 both allow nulls. If I have a relationship between aId and aId_1, and another relationship between aId and aId_2, where I set the delete rule for both to SET_NULL, then I get the error -"may cause cycles or multiple cascade paths"But its completely reasonable that I might wish to do this. The funny thing is that under Visual Studio, I can create a Data Set with these tables and using the designer, I can set the both foreign key relationships to Delete Rule Set Null and everything works as expected.So, I'm unsure now if I just need to set the Delete rules using the Dataset designer and not bother with them in the database itself.Any comments?Thanks,Barry. ...