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CHAPTER 8: Data Management with Core Data 255for ( NSUInteger i = 0, max = [abEmails count]; i < max; i++ ){NSString * label = [abEmails labelAtIndex: i];NSString * email = [abEmails valueAtIndex: i];// skip any weird entries which won't fit with our model validationif ( label == nil || email == nil )continue;EmailAddress * e = [[EmailAddress alloc] initWithEntity: entityinsertIntoManagedObjectContext: _context];e.label = ABLocalizedPropertyOrLabel(label);e.email = email;// rather than call the 'add to relationship' methods on myPerson,// we'll just set the to-one relationship on the email, which// does the same thinge.person = myPerson;}}// ensure it's valid -- if not, delete itif ( [e validateForUpdate: NULL] == NO ){[_context performBlockAndWait: ^{[_context deleteObject: e];}];continue;}Lastly, return to APAppDelegate.m and create the -importAddressBookData methodreferenced earlier. You need to create a new APAddressBookImporter object and call its-beginImportingWithCompletion: method, handling any errors reported as appropriate. You alsoneed to save the object context at this point—remember that the importer’s child context onlypushed data up to its parent when it saved; it didn’t actually cause the data to be written out topersistent storage. The complete method can be seen in Listing 8-23.Listing 8-23. Running the Importer- (void)importAddressBookData{APAddressBookImporter * importer = [[APAddressBookImporter alloc]initWithParentObjectContext: self.managedObjectContext];[importer beginImportingWithCompletion: ^(NSError *error) {if ( error ! = nil ){[NSApp presentError: error];}if ( [self.managedObjectContext hasChanges] ){[self.managedObjectContext performBlock: ^{NSError * saveError = nil;www.it-ebooks.info