DBFieldDef :: IsPersistentCollection - Does property define a persistent collection?
The function checks, whether the property defines a persistent collection when being defined in a persistent instance. When the same property is referred to in a transient instance, which makes the property transient as well, it will still return true.
When the function is called with an invalid property definition, it throws an exception.
Return value: Return value ( logical )
The function returns YES when the question was answered positively. Otherwise it returns NO.