Request: Support batch request

[EddieLukeAtmey]

Hi, I've just used MagicalRecord for my new project, and I found it quite interesting, efficiently. But I'd like to request a new feature for magical record (I suggest that it should work on iOS 8.0 and above), it is:

1. Batch update entity of a class:
   • Use a predicate to filter which entity should perform batch update.
   • Use a dictionary (key = propertyName, value = batchUpdatedValue) to perform update values. Note: In iOS 8.4 and above, we can use NSBatchUpdateRequest.
2. Batch Delete entity of a class:
   • Use predicate to filter which entity should perform batch delete. Note: in iOS 9.0 and above (this I'm not sure myself), we can use NSBatchDeleteRequest.
3. Batch Insert
   • Currently, I'm not using this, and I read that you already have import features, so I suppose I don't need to write anything here.

What do you think about this request?

[EddieLukeAtmey]

I see in issue #1104 and #1106, the batch update request support has been added. But, I haven't found any document about this, so I supposed it's not working yet, right?

Also, in my request, there's a batch delete request, so.... I supposed you got it :/

[pronebird]

@EddieLukeAtmey I've added those but then I closed my PR since I encountered some problems with stale managed objects after running batch requests. Not sure what was the deal, but I haven't used them since then, therefore couldn't even properly test it.

[mihaipuscasimprezzio]

Hi, any news about supporting batch update?

[hotngui]

Batch requests do not update the context as per Apple's 2015 WWDC presentation. They work directly on the persistent store.

[EddieLukeAtmey]

@hotngui so what? We can always and we always, as recommended, refresh the context after batch requests.