Re: ADC Core Data article

FROM : John C. Randolph
DATE : Wed Apr 06 02:55:31 2005

On Apr 5, 2005, at 5:18 PM, Dustin Voss wrote:

>
> On 5 Apr, 2005, at 4:14 PM, Scott Stevenson wrote:
>
>

>>
>> On Apr 5, 2005, at 2:49 PM, Philip Mötteli wrote:
>>
>>

>>>> Each entity definition in a managed object model requires the 
>>>> name of the entity and the name of the class used at runtime to 
>>>> represent that entity. By default, the class used is 
>>>> NSManagedObject, but the class may be either NSManagedObject or 
>>>> a subclass thereof.
>>>>

>>>
>>> I read that phrase 5 times. Is that really true? Only subclasses 
>>> of NSManagedObject get managed persistency from Core Data?
>>>

>>
>> Trying to implement transparent persistence without a persistent 
>> subclass is.... challenging.
>>

>
> I imagine Philip was thinking that persistence would be integrated 
> into NSObject, like Key-Value Coding. But personally, I prefer 
> having a distinct super-class that I can drop in-place of NSObject. 
> NSObject is overburdened as it is.


The reason that NSManagedObject is distinct from NSObject, is that 
there are many situations where persistence isn't needed or wanted. 
You should derive your model objects from NSManagedObject, not every 
object in your apps.

-jcr

John C. Randolph <<email_removed>> (408) 974-8819
Sr. Cocoa Software Engineer,
Apple Worldwide Developer Relations
http://developer.apple.com/cocoa/index.html