CoreData的增删改查
2015-08-03 10:50 甘雨路 阅读(309) 评论(0) 编辑 收藏 举报首先使用CoreData创建Demo,勾上CoreData选项
然后创建Entity对象,点击Add Entity(+)按钮
生成Entity对象
重命名双击Entity选项,然后输入Person
设置Person属性,点击Attributes选项中的+号,实现添加属性,并给属性命名,且添加属性相关的类型
然后command+N,创建NSManagedObject subclass
然后点击Next
然后勾上 CoreData_Demo选项,然再点击Next
接着勾上Person选项,再次点击Next
接下来,跟着系统的提示进行操作,最后生成Person类
下面是相关操作的代码
AppDelegate.h头文件的代码
1 #import <UIKit/UIKit.h> 2 #import <CoreData/CoreData.h> 3 4 @interface AppDelegate : UIResponder <UIApplicationDelegate> 5 6 @property (strong, nonatomic) UIWindow *window; 7 8 @property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext; 9 @property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel; 10 @property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator; 11 12 - (void)saveContext; 13 - (NSURL *)applicationDocumentsDirectory; 14 15 16 @end
AppDelegate.h实现文件的代码
1 #import "AppDelegate.h" 2 #import "RootViewController.h" 3 @interface AppDelegate () 4 5 @end 6 7 @implementation AppDelegate 8 9 10 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 11 self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 12 // Override point for customization after application launch. 13 self.window.backgroundColor = [UIColor whiteColor]; 14 15 self.window.rootViewController = [[RootViewController alloc] init]; 16 17 [self.window makeKeyAndVisible]; 18 return YES; 19 } 20 21 22 - (void)applicationWillTerminate:(UIApplication *)application { 23 // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:. 24 // Saves changes in the application's managed object context before the application terminates. 25 [self saveContext]; 26 } 27 28 #pragma mark - Core Data stack 29 30 @synthesize managedObjectContext = _managedObjectContext; 31 @synthesize managedObjectModel = _managedObjectModel; 32 @synthesize persistentStoreCoordinator = _persistentStoreCoordinator; 33 34 - (NSURL *)applicationDocumentsDirectory { 35 // The directory the application uses to store the Core Data store file. This code uses a directory named "com.YXYC.Test_CoreData_Test" in the application's documents directory. 36 return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject]; 37 } 38 39 - (NSManagedObjectModel *)managedObjectModel { 40 // The managed object model for the application. It is a fatal error for the application not to be able to find and load its model. 41 if (_managedObjectModel != nil) { 42 return _managedObjectModel; 43 } 44 NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"Test_CoreData_Test" withExtension:@"momd"]; 45 _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL]; 46 return _managedObjectModel; 47 } 48 49 - (NSPersistentStoreCoordinator *)persistentStoreCoordinator { 50 // The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. 51 if (_persistentStoreCoordinator != nil) { 52 return _persistentStoreCoordinator; 53 } 54 55 // Create the coordinator and store 56 57 _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; 58 NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"Test_CoreData_Test.sqlite"]; 59 NSError *error = nil; 60 NSString *failureReason = @"There was an error creating or loading the application's saved data."; 61 if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) { 62 // Report any error we got. 63 NSMutableDictionary *dict = [NSMutableDictionary dictionary]; 64 dict[NSLocalizedDescriptionKey] = @"Failed to initialize the application's saved data"; 65 dict[NSLocalizedFailureReasonErrorKey] = failureReason; 66 dict[NSUnderlyingErrorKey] = error; 67 error = [NSError errorWithDomain:@"YOUR_ERROR_DOMAIN" code:9999 userInfo:dict]; 68 // Replace this with code to handle the error appropriately. 69 // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 70 NSLog(@"Unresolved error %@, %@", error, [error userInfo]); 71 abort(); 72 } 73 74 return _persistentStoreCoordinator; 75 } 76 77 78 - (NSManagedObjectContext *)managedObjectContext { 79 // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) 80 if (_managedObjectContext != nil) { 81 return _managedObjectContext; 82 } 83 84 NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; 85 if (!coordinator) { 86 return nil; 87 } 88 _managedObjectContext = [[NSManagedObjectContext alloc] init]; 89 [_managedObjectContext setPersistentStoreCoordinator:coordinator]; 90 return _managedObjectContext; 91 } 92 93 #pragma mark - Core Data Saving support 94 95 - (void)saveContext { 96 NSManagedObjectContext *managedObjectContext = self.managedObjectContext; 97 if (managedObjectContext != nil) { 98 NSError *error = nil; 99 if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) { 100 // Replace this implementation with code to handle the error appropriately. 101 // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 102 NSLog(@"Unresolved error %@, %@", error, [error userInfo]); 103 abort(); 104 } 105 } 106 } 107 108 @end
RootViewController.h头文件相关的代码
1 #import <UIKit/UIKit.h> 2 3 @interface RootViewController : UIViewController 4 5 @end
RootViewController.h实现文件相关的代码
1 #import "RootViewController.h" 2 #import "AppDelegate.h" 3 @interface RootViewController () 4 5 @property (strong, nonatomic) AppDelegate *appDelegate; 6 7 @end 8 9 @implementation RootViewController 10 11 - (void)viewDidLoad { 12 [super viewDidLoad]; 13 self.appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate]; 14 // 存储数据 15 [self saveData]; 16 // 查询全部数据 17 [self readData]; 18 NSMutableArray *datas = [[NSMutableArray alloc] init]; 19 // 得到查询的结果(条件查询) 20 datas = [self getObjectsWithPredicate]; 21 // 删除 22 [self removeObjects]; 23 // 修改 24 [self changeObjects]; 25 } 26 27 /** 28 * 存储数据 29 */ 30 - (void)saveData 31 { 32 NSManagedObjectContext *object = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:self.appDelegate.managedObjectContext]; 33 [object setValue:@"GL" forKey:@"name"]; 34 [object setValue:@"female" forKey:@"sex"]; 35 36 } 37 38 /** 39 * 查询全部数据 40 */ 41 - (void)readData 42 { 43 // 实例化一个查询(Fetch)请求 44 NSFetchRequest *fetch = [[NSFetchRequest alloc] init]; 45 NSEntityDescription *object = [NSEntityDescription entityForName:@"Person" inManagedObjectContext:self.appDelegate.managedObjectContext]; 46 [fetch setEntity:object]; 47 48 NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:NO]; 49 NSLog(@"sort:%@",sort); 50 51 NSArray *sortarr = [[NSArray alloc] initWithObjects:sort, nil]; 52 [fetch setSortDescriptors:sortarr]; 53 54 NSError *error = nil; 55 // 让_context执行查询数据 56 NSArray *fetchresult = [self.appDelegate.managedObjectContext executeFetchRequest:fetch error:&error]; 57 58 for (NSManagedObject *object in fetchresult) { 59 NSLog(@"name:%@==sex:%@",[object valueForKey:@"name"],[object valueForKey:@"sex"]); 60 } 61 62 } 63 /** 64 * 条件查询 65 * 66 * @return 查询结果的Entity数组 67 */ 68 - (NSMutableArray *)getObjectsWithPredicate 69 { 70 NSError *error = nil; 71 // 实例化一个查询(Fetch)请求 72 NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"]; 73 // 条件查询 74 request.predicate = [NSPredicate predicateWithFormat:@"sex LIKE '*female'"]; 75 // 让_context执行查询数据 76 NSArray *array = [self.appDelegate.managedObjectContext executeFetchRequest:request error:&error]; 77 return [NSMutableArray arrayWithArray:array]; 78 } 79 /** 80 * 删除操作 81 */ 82 - (void)removeObjects 83 { 84 NSError *error = nil; 85 // 实例化查询请求 86 NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"]; 87 // 设置条件 88 request.predicate = [NSPredicate predicateWithFormat:@"name = 'LF'"]; 89 // 由上下文查询数据 90 NSArray *result =[self.appDelegate.managedObjectContext executeFetchRequest:request error:&error]; 91 // 打印条件结果,并删除对象 92 for (NSManagedObject *object in result) { 93 // 删除对象 94 [self.appDelegate.managedObjectContext deleteObject:object]; 95 } 96 // 删除后,保存数据 97 [self.appDelegate.managedObjectContext save:&error]; 98 } 99 /** 100 * 修改 101 */ 102 - (void)changeObjects 103 { 104 NSError *error = nil; 105 // 实例化查询请求 106 NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"]; 107 // 设置条件 108 request.predicate = [NSPredicate predicateWithFormat:@"name = 'GL'"]; 109 // 由上下文查询数据 110 NSArray *result =[self.appDelegate.managedObjectContext executeFetchRequest:request error:&error]; 111 // 修改对象 112 for (NSManagedObject *object in result) { 113 // 修改对象 114 [object setValue:@"GYL" forKey:@"name"]; 115 } 116 // 修改后,保存数据 117 [self.appDelegate.managedObjectContext save:&error]; 118 } 119 120 @end