Forgive me if this is a silly question but:
If my first table Customers has an auto CustomerNumber and composite keys [firstname],[lastname],[middleinitial] so as to protect from entering the same customer twice...
and my sales table has invoice number set as the primary key...
When I try to create the many to many relationship in a join table and enforce referential integrity, I get the warning "No unique index found for the referenced field of the primary table."
If I was to delete a customer, wouldn't the relationship in the many to many join table be orphaned? How then would I go about enforcing the referential integrity in a many to many table with other tables with composite keys? Or is it even necessary?
Hope that makes sense?