CODEWITHSUNDEEP
iosobjective-ccore-dataios7nsmanagedobjectid
user2182231
user2182231

Reputation: 111

How to get ObjectId correctly in CoreData IOS?

I am trying to store my unique records using CoreData ObjectId.Sometimes i am succeded to get ObjectID in this format

<x-coredata://FC004E6F-F3D6-420E-871E-3E281571FB8B/Register/p4>

through which i am able to retreive the id i.e 4.But sometimes it return in this format of ObjectId

<x-coredata:///Playlist/tC481615F-4ABA-4CDA-B703-D1E6303B455D3>

i.e NSTemporaryObjectID_Default which is so irritating.I clean my project from my IOS Simulator,Clean Xcode but it is not working perfectly.

This is my code to get object ID:

-(IBAction)TestButton:(id)sender
{
    appObject=(AppDelegate*)[[UIApplication sharedApplication]delegate];
    NSManagedObjectContext *context =[appObject managedObjectContext];
    NSManagedObject *playlistContact;
    NSManagedObjectID *moID = [playlistContact objectID];
    NSString *aString = [[moID URIRepresentation] absoluteString];
    NSArray *theComponents = [aString componentsSeparatedByString:@"/p"];
    NSInteger theZpk = [[theComponents lastObject] intValue];
    playlistId=[NSString stringWithFormat:@"%ld",(long)theZpk];
}

Please help me.

Upvotes: 0

Views: 2189

Answers (2)

Shmidt
Shmidt

Reputation: 16664

To get objectID use:

-(NSManagedObject *)existingObjectWithID:(NSManagedObjectID *)objectID
                               error:(NSError **)error

To get permanent objectID use obtainPermanentIDsForObjects, for example:

NSManagedObject *contact = [NSEntityDescription insertNewObjectForEntityForName:self.entityName inManagedObjectContext:context];
NSError *error = nil;
if (![context obtainPermanentIDsForObjects:
      @[contact] error:&error]) {
    NSLog(@"Couldn't obtain a permanent ID for object %@",
          error);
}

Upvotes: 1

Marcus S. Zarra
Marcus S. Zarra

Reputation: 46718

You should not be using ObjectID for that. If you are looking to use a primary key you really should be creating your own primary key and fetching off of that instead.

The ObjectID can and will change on you in several different situations causing numerous problems. It is intended to be used within the application during one life-cycle of the app. Using it across life cycles is not recommended.

Upvotes: 3

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