Core Data generic attribute type for abstract entity

Question

I have an abstract parent entity Datapoint with a number of attributes, and 3 child entities BinaryPoint, FloatPoint, and ScalePoint. Each child should have a value attribute, but of a different type (bool, float, and int respectively).

It seems like bad design to do anything other than make it an inherited attribute, but I can't find a way to do this. Is there any way to make the attribute generic in the parent entity but not in its children?

Thanks in advance.

What do you mean by 'generic' attribute? If I understood you well you want a parent 'Datapoint' to have and 'id' attribute called 'value', but 'BinaryPoint' must define it as a binary value, the 'ScalePoint' as a scalar and the 'FloatPoint' as a float, right? — Gianluca Tranchedone

Gianluca Tranchedone Gianluca Tranchedone · Accepted Answer · 2013-06-21T12:33:41

There is no way to do what you want to do in the Core Data Model Editor AFASIK. You'll need to pick a type of attribute, e.g. Binary Data, and handle the transformation from NSData to the actual value or viceversa yourself in code.

Core Data generic attribute type for abstract entity

1 Answers