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POFetching contacts based on tag
 

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  1. POFetching contacts based on tag
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    <p>I'm trying to <strong>modify</strong> a simple Core Data fetch request for contacts to only look for contacts with a relationship with a certain tag. Contact and Tag are both entities with a many-to-many relationship.</p> <p>I understand with Core Data I can do this by first fetching the <strong>Tag</strong> object, and then calling <strong>tag.contact</strong>, but I don't want to do it this way as the rest of the code is dependent on the fact that the fetchResultsController returns <strong>Contact</strong> objects, not <strong>Tag</strong> objects.</p> <p>If I were to do relational databasing, I could do a simple cross-table query and find all contacts with a certain tag. Is there a <strong>simple</strong> way I can replicate this via Core Data?</p> <pre><code>-(NSFetchedResultsController *) fetchedResultsController { //if fetch controller already exists if(_fetchedResultsController != nil) { return _fetchedResultsController; } //create a new fetch request NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Contact" inManagedObjectContext:[self managedObjectContext]]; [fetchRequest setEntity:entity]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"lastName" ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [fetchRequest setSortDescriptors:sortDescriptors]; //instantiate the fetch controller with the fetch request and sort by last name into sections _fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:[self managedObjectContext] sectionNameKeyPath:nil cacheName:nil]; //declare delegate of fetch controller as self _fetchedResultsController.delegate = self; NSLog(@"fetchResultsController Created"); return _fetchedResultsController; } </code></pre>
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    1. USAllen
    1. USAllen
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    1. COI am not able to understand the question. Is Tag an entity? how is it related with Contacts? is Sales also an entity? What is the relation between all these entities? On waht basis you want to fetch Contacts Entity?
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      1. USPuneet Sharma
    2. COyes tag <<->> contact, both are entities with a many-to-many relationship
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      1. USAllen
    3. COOk. And how do you want to fetch Contacts? Do you want all those Contacts with have a many to many relationship with Tag?
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      1. POFetching contacts based on tag
      1. USPuneet Sharma
 

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