Cocoa Mac app, bind NSTableColumn to an Entity

Question

Mac app with Core Data:
I have 3 entities:
A <-->> B <<--> C, C has a BOOLEAN atribute.

Now I want do display, in a 2 Column Table, the name of A (1st column) and a boolean value (2nd column) which based on the boolean values from C.

For example:

An Object from type A (called a) owns 3 Objects from Type B (called b1, b2, b3).
Each of these 3 Objects owns 1 Object from Type C (called c1, c2, c3).
If the boolean Attribute of one of these Objects (c1, c2, c3) is TRUE, the boolean in the 2nd column have to be true.

I have tried something like that (with a custom ArrayController Class):

[NSTableColumn bind:@"value" toObject:self withKeyPath:@"arrangedObjects.bc@sum.boolValue" options:nil];

The ArrayController self is in Entity Name mode with Entity Name: A.

Answer 1

Are you sure @sum should be after c? There are 3 objects of type b for each a right? so, "b" is the collection in your case.

From the KVC Guide :

Simple Collection Operators

Simple collection operators operate on the properties to the right of the operator in either an array or set.

And:

@sum

The @sum operator returns the sum of the values of the property specified by the key path to the right of the operator. Each number is converted to a double, the sum of the values is computed, and the total is wrapped as an instance of NSNumber and returned.

Have you tried:

@"arrangedObjects.b.@sum.c.boolValue"