Re: Strange error message

Anjo,

> Been thinking about this: the easiest thing I could come up with is a 
> databasecontext delegate that
>
> a) responds to databaseContextNewPrimaryKey(), then checks if the 
> entity in question is subclassed, then re-calc the root entity's max 
> key
> b) responds to databaseContextWillFireObjectFaultForGlobalID(), then 
> checks if the entity in question is abstract, tries every subclassed 
> entity in question and raise if there are more than one candidate 
> objects.
>
> Would that work? Does is make sense? At least you get some control 
> over the situation without having to mess with your model...

It's hard to tell off the bat.

I would however expect that object uniquing gets in your way. That is 
if you want to fetch Car with ID 1 and Bicycle with ID 1 exists already 
in the editing context, both will have a Vehicle ID 1 global ID. Thus 
the object is thought to exist already and no fault will be fired.

I guess the easiest solution to implement is to modify your EOModel at 
application launch time. You could have flagged all entities where 
children have IDs that are not unique with a special key in the 
userInfo dictionary. At runtime you remove these entities from the 
model, leaving only the child entities. You may want to first do a 
sanity check verifying that the parent entity is not referenced by any 
relationship. Thus errors introduced later on in the model would be 
detected promptly.

Pierre
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