Re: Seeking clarification on NSManagedObjectID

FROM : David Spooner
DATE : Tue Nov 06 17:19:32 2007

While I tend to agree with your interpretation, the three sections of 
the documentation I found which discuss uniquing do not explicitly 
answer my question.  I was hoping someone with implementation 
knowledge could provide a definitive answer so that I'm not making an 
incorrect assumption.

Thanks,
dave

On 6-Nov-07, at 8:50 AM, I. Savant wrote:

>> After reviewing the Core Data documentation the following is not 
>> clear
>> to me: If a managed object is deleted, is there a chance that its
>> object ID will be subsequently reused?

>
> http://developer.apple.com/documentation/Cocoa/Conceptual/CoreData/index.html#/
> /apple_ref/doc/uid/TP40001075
>
> "An NSManagedObjectID object is a universal identifier for a managed
> object, and provides basis for uniquing in the Core Data Framework. A
> managed object ID uniquely identifies the same managed object both
> between managed object contexts in a single application, and in
> multiple applications (as in distributed systems). Like the primary
> key in the database, an identifier contains the information needed to
> exactly describe an object in a persistent store ..."
>
>  With wording like "the basis for uniquing", and "like the primary
> key in the database", I take this to mean an ID is never reused.
> Further, I believe they use UUIDs so it's unlikely you'd ever be
> *able* to get the same ID generated for a managed object.
>
> --
> I.S.
>