1. 安装
源代码地址：MagicalRecord
通过 CocoaPods 安装：
pod "MagicalRecord"
2. 设置 CoreData 堆栈
1.导入 CoreData.framework 框架。
2.打开 AppDelegate.m 文件，增加以下方法：
#import "MagicalRecord.h" //导入头文件
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[MagicalRecord setupAutoMigratingCoreDataStack]; //设置堆栈
return YES;
}
- (void)applicationWillTerminate:(UIApplication *)application {
[MagicalRecord cleanUp]; //app退出时的清理工作
}
3.建立数据模型
我增加了一个 Person 类，在使用到该实体的类里导入 Model+CoreDataModel.h 文件，因为系统会帮你生成 Person 类文件，如果没自动生成则需要手动创建；选中模型文件 ——> Editor ——> Create NSManagedobject Subclass；com + b 编译一下，发现报文件重复错误，则把刚自动生成的文件删除，再使用 #import “Model+CoreDataModel.h” 就应该不会报错了，点进去也可以看到系统为你生成的类和属性。
3. 增删改查
3.1 添加数据
NSManagedObjectContext *context = [NSManagedObjectContext MR_defaultContext];
Person *per = [Person MR_createEntityInContext: context];
per.name = @"aaa";
per.age = 18;
per.headImg = UIImagePNGRepresentation([UIImage imageNamed: @"delete"]);
per.date = [NSDate date];
[context MR_saveToPersistentStoreAndWait];
3.2 删除数据
Person *person = [muArray objectAtIndex: indexPath.row];
[person MR_deleteEntity];//删除实体
[[NSManagedObjectContext MR_defaultContext] MR_saveToPersistentStoreAndWait];
//或者清空某个类的所有数据
[Person MR_truncateAll];
3.3 修改数据
Person *person = [muArray objectAtIndex: indexPath.row];
person.name = @"bbb";
[[NSManagedObjectContext MR_defaultContext] MR_saveToPersistentStoreAndWait];
3.4 查询数据
//从持久化存储（PersistantStore）中查询出所有的Person实体
NSArray *people = [Person MR_findAll];
//查询出所有的Person实体并按照 lastName 升序（ascending）排列
NSArray *peopleSorted = [Person MR_findAllSortedBy:@"lastName" ascending:YES];
//查询出所有的Person实体并按照 lastName 和 firstName 升序（ascending）排列
NSArray *peopleSorted = [Person MR_findAllSortedBy:@"lastName,firstName" ascending:YES];
//查询出所有的Person实体并按照 lastName 降序，firstName 升序（ascending）排列
NSArray *peopleSorted = [Person MR_findAllSortedBy:@"lastName:NO,firstName" ascending:YES大专栏 【magicalrecord】——coredata第三方封装>];
//或者
NSArray *peopleSorted = [Person MR_findAllSortedBy:@"lastName,firstName:YES" ascending:NO];
//查询出所有的Person实体 firstName 为 Forrest 的实体
Person *person = [Person MR_findFirstByAttribute:@"firstName" withValue:@"Forrest"];
3.5 高级查询
//使用 NSPredicate 来实现高级查询。
NSPredicate *peopleFilter = [NSPredicate predicateWithFormat:@"department IN %@", @[dept1, dept2]];
NSArray *people = [Person MR_findAllWithPredicate:peopleFilter];
//NSFetchRequest
NSPredicate *peopleFilter = [NSPredicate predicateWithFormat:@"department IN %@", departments];
NSFetchRequest *people = [Person MR_requestAllWithPredicate:peopleFilter];
//自定义 NSFetchRequest
NSPredicate *peopleFilter = [NSPredicate predicateWithFormat:@"department IN %@", departments];
NSFetchRequest *peopleRequest = [Person MR_requestAllWithPredicate:peopleFilter];
[peopleRequest setReturnsDistinctResults:NO];
[peopleRequest setReturnPropertiesNamed:@[@"firstName", @"lastName"]];
NSArray *people = [Person MR_executeFetchRequest:peopleRequest];
//查询实体个数
//返回的是 NSNumber 类型
NSNumber *count = [Person MR_numberOfEntities];
//基于 NSPredicate 查询条件过滤后的实体个数
NSNumber *count = [Person MR_numberOfEntitiesWithPredicate:...];
//返回的是 NSUInteger 类型
+ (NSUInteger) MR_countOfEntities;
+ (NSUInteger) MR_countOfEntitiesWithContext:(NSManagedObjectContext *)context;
+ (NSUInteger) MR_countOfEntitiesWithPredicate:(NSPredicate *)searchFilter;
+ (NSUInteger) MR_countOfEntitiesWithPredicate:(NSPredicate *)searchFilter inContext:(NSManagedObjectContext *)context;
//合计操作
NSInteger totalFat = [[CTFoodDiaryEntry MR_aggregateOperation:@"sum:" onAttribute:@"fatCalories" withPredicate:predicate] integerValue];
NSInteger fattest = [[CTFoodDiaryEntry MR_aggregateOperation:@"max:" onAttribute:@"fatCalories" withPredicate:predicate] integerValue];
NSArray *caloriesByMonth = [CTFoodDiaryEntry MR_aggregateOperation:@"sum:" onAttribute:@"fatCalories" withPredicate:predicate groupBy:@"month"];