Fix checks for what types of columns can be optional
Fix checks for what types of columns can be optional

ul7290/realm-cocoa,tenebreux/realm-cocoa,ul7290/realm-cocoa,ul7290/realm-cocoa,ul7290/realm-cocoa,tenebreux/realm-cocoa,ul7290/realm-cocoa,tenebreux/realm-cocoa,tenebreux/realm-cocoa,tenebreux/realm-cocoa