Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>(I'll write this up assuming you're using an <code>NSFetchedResultsController</code> to drive your tableview. If you're not, I recommend checking it out.)</p> <p>An interesting feature of <code>NSFetchedResultsController</code>'s sectioning abilities: although the property you <em>sort</em> on must be a modeled property (because sqlite does the actual sorting), the property you <em>group the sections with</em> need not be. The only requirement is that the grouping be consistent with the ordering. (i.e., sorting by the sort property will put the objects with matching group properties next to each other.)</p> <p>So just add something like this to your modeled object class:</p> <pre><code>// in interface @property (nonatomic, readonly) NSString *mediumFormattedDate; // in impl -(NSString *)mediumFormattedDate { // this can be fancier if you need a custom format or particular timezone: return [NSDateFormatter localizedStringFromDate:self.date dateStyle:NSDateFormatterMediumStyle timeStyle:NSDateFormatterNoStyle]; } </code></pre> <p>(no need to mention mediumFormattedDate in the .xcdatamodel at all.)</p> <p>Then go ahead and sort your objects by the date property, but group them by your new property. When you create your <code>NSFetchedResultsController</code>, do so along these lines:</p> <pre><code>NSFetchRequest *fr = [NSFetchRequest fetchRequestWithEntityName:@"MyFancyEntity"]; NSSortDescriptor *sd = [NSSortDescriptor sortDescriptorWithKey:@"date" ascending:YES]; [fr setSortDescriptors:[NSArray arrayWithObject:sd]]; NSFetchedResultsController *frc = [[NSFetchedResultsController alloc] initWithFetchRequest:fr managedObjectContext:myManagedObjectContext sectionNameKeyPath:@"mediumFormattedDate" cacheName:nil]; // then do stuff with frc </code></pre> <p>That's all it takes! I've done this in a few apps to get date grouping and it works well.</p>
    singulars
    1. This table or related slice is empty.
    1. POCore Data sort tableview by formatted date
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USrgeorge
    1. USrgeorge
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POCore Data sort tableview by formatted date
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    1. COThanks very much! I will try this in the morning and let you know how it goes!
      singulars
      1. PO
      1. USW Dyson
    2. COOne question, what is setting the value of self.date in mediumFormattedDate?
      singulars
      1. PO
      1. USW Dyson
    3. COThis is the error I'm getting: the entity InTextEntity is not key value coding-compliant for the key "mediumFormattedDate".'
      singulars
      1. PO
      1. USW Dyson
 

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