iosCoreData框架的使用，对上下文数据的增删改查，表与表之间的关联，1对多，1对1，谓词查询，多表连接(一)

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- (void)viewDidLoad {

[super viewDidLoad];



[self _creatTable];//插入数据



// [self _query];// 查询数据





// KVC很霸道，即使readonly通过kvc也可赋值，kvo精华

// Book * book = [[Book alloc]init];

//// book.name = @"book1";

// [book setValue:@"book2" forKey:@"name"];

// NSLog(@"%@",book.name);

}



#pragma mark - _query查询

- (void)_query{

// 初始化模型

NSManagedObjectModel * model = [NSManagedObjectModel mergedModelFromBundles:nil];



// 创建基础库协调器

NSPersistentStoreCoordinator * psc = [[NSPersistentStoreCoordinator alloc]initWithManagedObjectModel:model];



// 获取沙盒路径

NSString * path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];

path = [path stringByAppendingPathComponent:@"coreData.sqlite"];

NSLog(@"%@",path);

NSURL * url = [[NSURL alloc]initFileURLWithPath:path];



//为协调器加载基础库路径和基础库类型

[psc addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:nil];

// 创建上下文

NSManagedObjectContext * context = [[NSManagedObjectContext alloc]init];

context.persistentStoreCoordinator = psc;





// 初始化查询请求

NSFetchRequest * request = [[NSFetchRequest alloc]initWithEntityName:@"Teacher"];



// 谓词过滤（查询条件）

#pragma mark '='

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"name = %@",@"zhangks"];

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"name = 'zhangks'"];

#pragma mark '>'

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"age >10"];

// NSP





redicate * predict = [NSPredicate predicateWithFormat:@"name in %@",@[@"zhangsk",@"jack"]];

#pragma mark 'like'模糊查询

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"name like %@",@"zha*"];

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"name like %@",@"*zha*"];

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"name like %@",@"*zha"];







#pragma mark 'and'和'&&'模糊查询

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"name = %@ and age = 19",@"zhangks"];

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"name = %@ && age = 19",@"zhangks"];



#pragma mark 'between'模糊查询

// 方式1

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"age between {20,30}"];



// 方式2

// NSPredicate * predict = [NSPredicate predicateWithFormat:@"age between %@",@[@"10",@"29"]];

// predict = [NSPredicate predicateWithFormat:predict.predicateFormat];



// request.predicate = predict;



// 数据排序 ascending=YES顺序，ascending=NO倒序

NSSortDescriptor * sort = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];

request.sortDescriptors = @[sort];



NSError * error ;

// 执行查询语句

NSArray * array = [context executeFetchRequest:request error:&error];// 查询结果返回的是数组

// NSInteger count = [context countForFetchRequest:request error:&error];

// 查询结果的个数，返回nsinteger





// NSLog(@"%li",count);



/*

// // KVC方式获取

// for (NSManagedObject * student in array) {

// NSLog(@"————————————————————%@,%li",[student valueForKey:@"name"],[[student/Users/zhangxin/Desktop/OC/UI/5.19/5.21coreData/testtestcoredata/testtestcor