I'm modifying a foreign key from one column to two. I dropped the original foreign key from the child table, populated the new columns, and then created the new key.
I forgot to populate the new column in the child table, so all the relationships looked like this: Child Parent ----- ------ Col1:null -> Col1:A Col2:B -> Col2:B The new foreign keys were created without any errors. Since (null,B) doesn't match anything, shouldn't the creation have failed?