Re: Multi-storage Core Data

FROM : Jim Correia
DATE : Sat May 17 21:54:45 2008

On May 17, 2008, at 3:00 PM, Keary Suska wrote:

> on 5/17/08 10:27 AM, <email_removed> purportedly said:
>

>> I'm trying to build a Core Data app for which some data is user-
>> provided and
>> some data is shipped with the program. Consider a travel itinerary 
>> program
>> for instance where the user has a trip from airport A to airport B. 
>> If the
>> program includes data about the airports themselves, that shouldn't 
>> be
>> stored in the same storage as the user's flight numbers. One is 
>> document
>> based and the other is shared across documents.
>>
>> I understand the basic idea of using Fetched Properties and how to 
>> create
>> them. What I'm not clear on is how to define a fetched property in 
>> one store
>> against objects in another store, or how to tie multiple stores 
>> together
>> into a context. Is there a good explanation or sample code for this 
>> kind of
>> setup?

>
> I don't believe there is any support for this, at least not 
> "automatically".
> You would have to provide glue code for any interactions between 
> Managed
> Object Contexts (MOCs), since each MOC is married to one storage.


This is not quite correct.

A MOC is associated with a persistent store coordinator. A PSC can 
have multiple stores associated with it.

What you do not get for free is cross-store relationships.

Jim