Core Data - Associate a Quantity to a Relationship

Question

I have a Core Data entity called "Item" and it represents an item in a store so it has a name, price, and a few other attributes.

I would like to be able to create lists of these items and I am having some trouble figuring out how to do it.

The problem is that I need to be able to associate a quantity for each item in the list AND I need to be able to add the item to multiple lists.

So for example, say I have an item called "Bread" and I want to add it to two different lists with different quantities associated with each relationship.

I see that the documentation for Core Data says that a userInfo dictionary can be associated with a relationship but I can't seem to locate any information that would indicate whether or not that would work for me.

Any ideas?

Answer 1

This is probably not the best place for a userInfo dictionary. Instead, create a new entity, which has a list releationship, an item relationship, and a quantity attribute. When you add Bread to a list, you actually add this 'link' object, and hook up the Item and List relationships, then set its quantity.