Can someone tell me the reason for setting up the relationship between BNRItem and BNRAssetType? I don’t really see the point of creating this relationship between the two entities.
BNRAssetType is serving as a container for all BNRItems of a certain type. It logically groups items of a certain type. Retrieving items of certain type will only involve fetching a single BNRAssetType of a certain type. Without a BNRAssetType you’ll have too give BNRItem an attribute to keep track of its type and then fetch BNRItems by using a predicate.
Its usefulness is not very evident for this situation, however it illustrates how to create model objects and create relationships.