ios CoreData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

来源：互联网发布：sleep linux 头文件编辑：程序博客网时间：2024/05/16 01:14

这里是只是代码，因为博客插入图片效果不是很好，我自己写的总结比较详细，有兴趣的朋友可以在评论里留下邮箱，我收到后会发给大家。

转载注明出处，重视原创者的劳动成果，谢谢！

- (void)viewDidLoad {

[superviewDidLoad];

[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 = [NSManagedObjectModelmergedModelFromBundles:nil];

//创建基础库协调器

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

// 获取沙盒路径

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

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

NSLog(@"%@",path);

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

//为协调器加载基础库路径和基础库类型

[psc addPersistentStoreWithType:NSSQLiteStoreTypeconfiguration:nilURL:url options:nilerror:nil];

// 创建上下文

NSManagedObjectContext * context = [[NSManagedObjectContextalloc]init];

context.persistentStoreCoordinator = psc;

// 初始化查询请求

NSFetchRequest * request = [[NSFetchRequestalloc]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"];

// NSPredicate * 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 = [NSSortDescriptorsortDescriptorWithKey:@"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/testtestcoredata/ViewController.m valueForKey:@"age"] integerValue]);

// }

// // 子类KVC方式获取

// for (Student * student in array) {

// NSLog(@"%li,%@",[student.age integerValue],[student valueForKey:@"name"]);

// }

*///KVC

//通过映射对象获取

for (Teacher * teacherin array) {

NSLog(@"%@",teacher.name);

}

#pragma mark _creatTable

- (void)_creatTable{

// 初始化模型

NSManagedObjectModel * model = [NSManagedObjectModelmergedModelFromBundles:nil];

//创建基础库协调器

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

// 获取沙盒路径

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

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

NSLog(@"%@",path);

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

//为协调器加载基础库路径和基础库类型

[psc addPersistentStoreWithType:NSSQLiteStoreTypeconfiguration:nilURL:url options:nilerror:nil];

// 创建上下文

NSManagedObjectContext * context = [[NSManagedObjectContextalloc]init];

context.persistentStoreCoordinator = psc;

// // 插入数据

// NSManagedObject * student = [NSEntityDescription insertNewObjectForEntityForName:@"Student" inManagedObjectContext:context];

// [student setValue:@"zhangks" forKey:@"name"];

// [student setValue:@(19) forKey:@"age"];

// NSManagedObject * teacher = [NSEntityDescription insertNewObjectForEntityForName:@"Teacher" inManagedObjectContext:context];

// [teacher setValue:@"zhqo" forKey:@"name"];

// 插入数据新建 NSManagedObject subclass类 ,自动根据model中entity（实体）的表创建出类（继承自NSManagedObject，拥有NSManagedObject的属性和方法）所以直接用类名创建即可

// Student * student = [NSEntityDescription insertNewObjectForEntityForName:@"Student" inManagedObjectContext:context];

// student.name = @"jack";

// student.age = @(29);

// Teacher * teacher = [NSEntityDescription insertNewObjectForEntityForName:@"Teacher" inManagedObjectContext:context];

// teacher.name = @"limei";

// 初始化查询请求

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

//谓词过滤（查询条件）

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

// request.predicate = predict;

NSArray * array = [context executeFetchRequest:request error:nil];

for (Teacher * teacherin array) {

Student * student1 = [NSEntityDescriptioninsertNewObjectForEntityForName:@"Student"inManagedObjectContext:context];

student1.name =@"jim";

student1.age =@(12);

student1.relationship = teacher;

NSLog(@"%@,%@",teacher.name,student1.relationship.name);

//// teacher.name = @"liuwu";

//// [context deleteObject:teacher];

}

// NSSet * deleteSet = [context deletedObjects];// 删除（未save），执行删除语句后未保存前，缓存中（库表未修改）存储的删除数据

// NSSet * insertSet = [context insertedObjects];//同上

// 保存

NSError * error;

[contextsave:&error];

}

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