Re: Representing an object graph
Re: Representing an object graph
- Subject: Re: Representing an object graph
- From: Chris Hanson <email@hidden>
- Date: Thu, 15 Dec 2016 19:43:03 -0800
On Dec 15, 2016, at 7:24 PM, Daryle Walker <email@hidden> wrote:
>
> On Dec 6, 2016, at 10:18 PM, Chris Hanson <email@hidden <mailto:email@hidden>> wrote:
>>
>> On Dec 5, 2016, at 4:18 PM, Daryle Walker <email@hidden <mailto:email@hidden>> wrote:
>>
>>> I've heard that Core Data is a object graph and persistence library. What if you want just the first part? The graph seems like a neat way to save on modeling code, the external format is not database-ish at all (so the capability for custom export formats won't help). Can I just not use the persistence part and use custom save & load functions? Or do I have to (or should) give up on Core Data?
>>
>> This is exactly the sort of thing that subclassing NSAtomicStore <https://developer.apple.com/reference/coredata/nsatomicstore> lets you do.
>>
>> There are only a few methods to override, and then you can just use one of your own documents as if it were one of the built-in persistent store types.
>
> I have looked into that, that’s why I wrote in:
>
>>> the external format is not database-ish at all (so the capability for custom export formats won't help)
>
> The store format assumes there’s at least one field in a record that can be used like a database(-ish) index. Custom stores can’t help if the data is too dumb to have such a qualifying field.
What do you mean?
Most atomically read/written file formats should be supportable as an NSAtomicStore. Object IDs can be purely an in-memory construct for such a store, for example based on the order an object was (initially) read or instantiated.
-- Chris
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