数据处理之CoreData

- (void)addPerson {
    
    //添加步骤
    //1: 创建person实体对象, 然后告诉"context", 让它做好准备, 将这个对象添加到数据库中
    
    //实例对象有两种方式 [初始化对象需要借用NSEntityDescription]
    //第一种
//    Person *person = [NSEntityDescription insertNewObjectForEntityForName:@"person" inManagedObjectContext:self.managedObjectContext];
    
    //第二种
    //创建一个entity实体
    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Person" inManagedObjectContext:self.managedObjectContext];
    //创建person对象
    Person *per = [[Person alloc]initWithEntity:entityDescription insertIntoManagedObjectContext:self.managedObjectContext];
    //2.给对象属性赋值
    per.personName = @"MBBoy";
    per.personGender = @"Unknow";
    per.personAge = @10;
    //将车的对象通过实体描述类创建出来
    Car *audiCar = [NSEntityDescription insertNewObjectForEntityForName:@"Car" inManagedObjectContext:self.managedObjectContext];
    
    audiCar.price = @300000;
    audiCar.color = @"白色";
    audiCar.brand = @"奥迪A7";
    
    Car *benchiCar = [NSEntityDescription insertNewObjectForEntityForName:@"Car" inManagedObjectContext:self.managedObjectContext];
    
    benchiCar.price = @500000;
    benchiCar.color = @"红色";
    benchiCar.brand = @"奔驰SUV";
    
    //将两辆车放在集合中存储然后进行赋值
    NSSet *carSet = [NSSet setWithObjects:audiCar, benchiCar, nil];
    
    per.personCar = carSet;
    
    
    
    //3.将对象存入数据库
    BOOL result = [_managedObjectContext save:nil];
    
    //4.判断是否插入成功
    if (result) {
        NSLog(@"添加数据成功");
    } else {
        NSLog(@"添加数据失败");
    }
}