1、NSManagedObjectModel:管理的对象模型,相当于实体,不过它包含了实体间的关系

2、NSManagedObjectContext：管理的对象上下文,操作实际内容,作用：插入数据 查询 更新 删除

3、NSPersistentStoreCoordinator：持久化存储助理,相当于数据库的连接器

4、NSFetchRequest:获取数据的请求,相当于查询语句

5、NSPredicate:相当于查询条件

6、NSEntityDescription:实体结构

7、后缀名为.xcdatamodel的包,里面的.xcdatamodel文件，用数据模型编辑器编辑,编译后为.MOMD或.MOM文件;

操作步骤：

一、建立模型对象

#import <UIKit/UIKit.h>

#import <CoreData/CoreData.h>

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) ViewController *viewController;

@property(strong,nonatomic,readonly)NSManagedObjectModel* managedObjectModel;

@property(strong,nonatomic,readonly)NSManagedObjectContext* managedObjectContext;

@property(strong,nonatomic,readonly)NSPersistentStoreCoordinator* persistentStoreCoordinator;

@end

//托管对象

-(NSManagedObjectModel *)managedObjectModel

{

if (_managedObjectModel!=nil) {

return _managedObjectModel;

}

// NSURL* modelURL=[[NSBundle mainBundle] URLForResource:@"CoreData" withExtension:@"momd"];

// _managedObjectModel=[[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

_managedObjectModel=[[NSManagedObjectModel mergedModelFromBundles:nil] retain];

return _managedObjectModel;

}

//持久化存储协调器

-(NSPersistentStoreCoordinator *)persistentStoreCoordinator

{

if (_persistentStoreCoordinator!=nil) {

return _persistentStoreCoordinator;

}

// NSURL* storeURL=[[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"CoreaData.CDBStore"];

// NSFileManager* fileManager=[NSFileManager defaultManager];

// if(![fileManager fileExistsAtPath:[storeURL path]])

// {

// NSURL* defaultStoreURL=[[NSBundle mainBundle] URLForResource:@"CoreData" withExtension:@"CDBStore"];

// if (defaultStoreURL) {

// [fileManager copyItemAtURL:defaultStoreURL toURL:storeURL error:NULL];

// }

// }

NSString* docs=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject];

NSURL* storeURL=[NSURL fileURLWithPath:[docs stringByAppendingPathComponent:@"CoreData.sqlite"]];

NSLog(@"path is %@",storeURL);

NSError* error=nil;

_persistentStoreCoordinator=[[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];

if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {

NSLog(@"Error: %@,%@",error,[error userInfo]);

}

return _persistentStoreCoordinator;

}

//托管对象上下文

-(NSManagedObjectContext *)managedObjectContext

{

if (_managedObjectContext!=nil) {

return _managedObjectContext;

}

NSPersistentStoreCoordinator* coordinator=[self persistentStoreCoordinator];

if (coordinator!=nil) {

_managedObjectContext=[[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];

[_managedObjectContext setPersistentStoreCoordinator:coordinator];

}

return _managedObjectContext;

}

-(NSURL *)applicationDocumentsDirectory

{

return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];

}

@end

[fetchedResultsController objectAtIndexPath]:返回指定位置的数据.

[fetchedResultsController sections]:获取section数据,返回的是NSFetchedResultsSectionInfo数据