Re: CoreData async fetch request
Re: CoreData async fetch request
- Subject: Re: CoreData async fetch request
- From: Luther Baker <email@hidden>
- Date: Fri, 2 Oct 2009 22:40:05 -0500
I'm fairly new to Core Data but I do believe that when tieing an
NSFetchedResultsController with an NSManagedObjectContext and an
NSTableViewController, (yes, this is an iPhone example) indeed, results for
the NSTableView are retrieved lazily, ie: as necessary.
I do not know how this is implemented but I think it implies that what you
ask may, in fact, be possible to a certain extent unless Core Data on the
iPhone is ahead of the Mac library.
-Luther
On Fri, Oct 2, 2009 at 7:48 PM, David Melgar <email@hidden> wrote:
> Is there a way to do an asynchronous fetch request against Core data
> returning partial results?
>
> The only means I've found to fetch is via the [ManagedObjectContext
> executeFetchRequest] method.
> And there does not seem to be a way to retrieve partial results. In the
> Core Data Programming Guide under Core Data performance, it specifically
> states that there is not an equivalent to database cursors. You cannot
> retrieve partial results then get the next set.
>
> So, bottom line, if I'm working with a large set of data and execute a long
> running query, I cannot display any result until everything is returned.
> And if the user makes a mistake and requests something with an unreasonably
> large response set, I don't have a way to page through it, I can either get
> everything or truncate the result.
>
> Frankly, these seem like basic requirements for interacting with data.
> 1) Asynchronous non-blocking requests
> 2) Ability to work through a partial result
>
> I don't understand why Coredata doesn't provide these basic functions. Is
> there a way that I'm not seeing?
>
> Obviously, Apple's own Spotlight could not use something like Coredata,
> since it heavily relies on returning asynchronous partial results.
>
> Frankly, this is my second application I've attempted to use Coredata to
> find it come up surprisingly short. The first time the issue was core data
> not being thread safe.
>
> What is the target market for Core Data? Why sort of application is ideal
> for its use? What size data store? Right now it escapes me.
>
> Thanks
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