The Core iOS Developer’s Cookbook, Fifth Edition

Querying the Database

Retrieve objects from the database by performing fetch requests. A fetch request describes your search criteria for selecting objects. It’s passed through to Core Data and used to initialize a results object that contains an array of fetched objects that meet those criteria. Here is a sample fetch method that saves the resulting fetched results to a local instance variable (_fetchedResultsController) associated with a helper class property:

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- (void)fetchItemsMatching:(NSString *)searchString         forAttribute:(NSString *)attribute         sortingBy:(NSString *)sortAttribute {     // Build an entity description     NSEntityDescription *entity = [NSEntityDescription         entityForName:_entityName ...