CKCoreDataHelper

An implementation of Core Data Helper origin from Textbook: 《Learning Core Data for iOS》.

Installation:

Pod

pod 'CKCoreDataHelper'

Usage:

Core Data Setup

// Your database file name
NSString *storeFileName = @"test.sqlite";

// Initialized a core data manager
CKCoreDataManager *manager = [CKCoreDataManager sharedInstanced];

// Setup core data manager with given store file
NSError *error;
BOOL flag = [manager setupCoreDataWithStoreFileName:storeFileName // Store file name
                               lightWeightMigration:YES           // enable lightweight data migration
                                              error:&error];      // get the error if init failed

Import data

There are two importer you can use to import data into persistent store. One for XML format, another for JSON format.

XML

// Initialize
_importer = [[CKCoreDataXMLImporter alloc]
                 initWithCoordinator:self.manager.coordinator
                 entitiesUniqueAttributes:@{@"Product": @"name",
                                            @"Shop": @"name"}];

NSURL *productXML = [bundle URLForResource:@"preload_product" withExtension:@"xml"];
    
[_importer importDataFrom:shopXML                                         // XML URL Path
                forEntity:@"Shop"                                         // The name for the Entity you need to import to
               completion:^(BOOL success, NSError * _Nullable error) {    // A callback when import finished.
                   XCTAssertTrue(success);
                   XCTAssertNil(error);
               }];

JSON

// Initialize
_importer = [[CKCoreDataJSONImporter alloc]
                 initWithCoordinator:self.manager.coordinator
                 entitiesUniqueAttributes:@{@"Product": @"name",
                                            @"Shop": @"name"}];

NSURL *path = [bundle URLForResource:@"preload_product_withoutrel" withExtension:@"json"];

[_importer importDataFrom:path
                forEntity:@"Product"
               completion:^(BOOL success, NSError * _Nullable error) {
                   XCTAssertTrue(success);
                   XCTAssertNil(error);
               }];

Entity CURD

Retrieve record

NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Entity"];
NSArray *results = [_manager.context executeFetchRequest:fetchRequest error:nil];

Sorting

NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"attribute Name" ascending:YES];
[fetchRequest setSortDescriptors:@[sort]];

Filter (Using NSPredicate). NSPredicate manual

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF.name == %@", @"Enix"];
[fetchRequest setPredicate:predicate];

Filter (Fetch Request Template)

1. Select Model.xcdatamodeld
2. Editor > Add Fetch Request
3. Set a name for your fetch request，eg, fetchByName
4. Add filtering expression
5. Get your fetch request template in code:

NSFetchRequest *req = [[_manager model]
                       fetchRequestTemplateForName:@"your fetch request name"];

Create Entity instance

Entity *newItem = [NSEntityDescription insertNewObjectForEntityForName:@"Entity"
                                                inManagedObjectContext:context];

Delete record

// Get the record which is pending to remove
NSArray *results = [[coreDataHelper context] executeFetchRequest:fetchRequest error:nil];

// Delete the record
[[_manager context] deleteObject:[results firstObject]];

Save

NSError *error = nil;
[context save:&error];