Databases
StackOverflow2013
Postsdbo
PONSFetchedResultsController not sorting on initial fetch
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PONSFetchedResultsController not sorting on initial fetch
    primarykey
    data
    text
    <p>I am having a Core Data problem with <code>NSFetchedResultsController</code>. I have a one to many relationship between a parent and child entity. The array in the <code>childFetchedResults.fetchedObjects</code> property is NOT sorted by <code>number</code> (number is an int32 property in the model). It doesn't seem to matter if I use the <code>MagicalRecord</code> convenience category methods or not.</p> <pre><code>NSFetchRequest *req = [Child MR_requestAllSortedBy:@"number" ascending:YES withPredicate:[NSPredicate predicateWithFormat:@"parent = %@", self.parent]]; childFetchedResults = [[NSFetchedResultsController alloc] initWithFetchRequest:req managedObjectContext:[NSManagedObjectContext MR_defaultContext] sectionNameKeyPath:nil cacheName:nil]; childFetchedResults.delegate = self; NSError *error; [childFetchedResults performFetch:&amp;error]; NSLog(@"fetched objects: %@", childFetchedResults.fetchedObjects); </code></pre> <p>However, if I sort the array of fetched objects using the exact same sort descriptor, it works fine: </p> <pre><code>NSLog(@"fetched objects: %@", [childFetchedResults.fetchedObjects sortedArrayUsingDescriptors:[NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"number" ascending:YES]]]); </code></pre> <p>I gather you can only use comparators which Core Data can pass on to the SQLite store when specifying sort descriptors for a fetch request. But I feel like that shouldn't matter in this case since sorting by a number has got to be supported by SQLite.</p> <p>Anyone solved this? I feel like it's a similar issue to the one described here: <a href="https://stackoverflow.com/questions/10109115/nssortdescriptor-not-being-called">NSSortDescriptor not being called</a>.</p> <p>As for <code>MR_requestAllSortedBy</code>, it's in <code>MagicalRecord</code>, here is the implementation:</p> <pre><code>+ (NSFetchRequest *) MR_requestAllSortedBy:(NSString *)sortTerm ascending:(BOOL)ascending inContext:(NSManagedObjectContext *)context { NSFetchRequest *request = [self MR_requestAllInContext:context]; NSSortDescriptor *sortBy = [[NSSortDescriptor alloc] initWithKey:sortTerm ascending:ascending]; [request setSortDescriptors:[NSArray arrayWithObject:sortBy]]; return request; } </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USehope
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. PONSFetchedResultsController not sorting on initial fetch
      1. This table or related slice is empty.
      1. VTUpMod
    1. COProvide the code for `[Child MR_requestAllSortedBy:@"number" ascending:YES withPredicate:[NSPredicate predicateWithFormat:@"parent = %@", self.parent]];`. Then, why first you sort first with two different descriptor (first by number and then by date)? Could you provide more info about your model? Thanks.
      singulars
      1. PONSFetchedResultsController not sorting on initial fetch
      1. USLorenzo B
    2. COSorry. it's number in both, copy paste problem. The model has two entities, Parent and Child. Parent has a one to many relationship to Child. The number attribute on the Child is just a property to preserve the display order -- the children are reorderable via tableview editing.
      singulars
      1. PONSFetchedResultsController not sorting on initial fetch
      1. USehope
    3. CO--moved this into question
      singulars
      1. PONSFetchedResultsController not sorting on initial fetch
      1. USehope
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload