包括：
- CoreData的初始化(非最新coredata)
- CoreData的数据操作
- 同一个数据库内表的关联
- 多个数据库简单使用
1，CoreData的初始化(非最新coredata)
- 1.1，创建数据库模型Data Model
Snip20170104_1.png
- 1.2，创建NSManagedObject
Snip20170104_2.png
- 1.3， 代码进行初始化
//1，创建模型，并与文件进行关联，如果只有一个数据库，可以字节用nil表示
//方式一：在只有一个数据库的时候
// NSManagedObjectModel *model = [NSManagedObjectModel mergedModelFromBundles:nil];
//方式二：在有多个数据库的时候会有多个数据库文件夹，所以需要指定特定的数据库文件夹，momd是默认数据库文件夹后缀名，如Company.momd
NSURL *url = [[NSBundle mainBundle] URLForResource:@"Company" withExtension:@"momd"];
NSManagedObjectModel *model = [[NSManagedObjectModel alloc] initWithContentsOfURL:url];
//2,创建调度器，并设置存储路径
NSPersistentStoreCoordinator *coordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"Company.sqlite"];
NSURL *url01 = [NSURL fileURLWithPath:path];//指定存储的文件名
NSError *error;
[coordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url01 options:nil error:&error];
//3, 创建上下文，并于调度器进行关联
NSManagedObjectContext *context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
context.persistentStoreCoordinator = coordinator;
2，CoreData的数据操作
- 2.1， 增加数据
- 多次数据添加只需要一次save即可
//1.1, 增加数据
Employee *employee01 = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
employee01.name = [NSString stringWithFormat:@"Jake"];
employee01.height = @(1.59 + arc4random_uniform(6)*0.1);
employee01.age = @(26+arc4random_uniform(4));
Employee *employee02 = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
employee02.name = [NSString stringWithFormat:@"Mike"];
employee02.height = @(1.59 + arc4random_uniform(6)*0.1);
employee02.age = @(26+arc4random_uniform(4));
NSError *errror;
[self.context save:&errror];
if (errror) {
NSLog(@"%@",errror);
}
/*
for (int i=0; i<100; i++) {
Employee *employee = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
employee.name = [NSString stringWithFormat:@"Jake"];
employee.height = @(1.59 + arc4random_uniform(6)*0.1);
employee.age = @(26+arc4random_uniform(4));
Employee *employee01 = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
employee01.name = [NSString stringWithFormat:@"Mike"];
employee01.height = @(1.59 + arc4random_uniform(6)*0.1);
employee01.age = @(26+arc4random_uniform(4));
NSError *errror;
[self.context save:&errror];
if (errror) {
NSLog(@"%@",errror);
}
}
*/
- 2.2， 查询数据
- （因为删除和更新都是在查询的基础上做的，所以这里先进行查询操作）
//1, 创建请求
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
request.predicate = [NSPredicate predicateWithFormat:@"age < 28"];
NSSortDescriptor *sort01 = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES];
request.sortDescriptors = @[sort01];
//2, 执行请求，返回数据
NSError *error;
NSArray *array = [self.context executeFetchRequest:request error:&error];
// NSLog(@"%@", array);
//3, 解析数据
[array enumerateObjectsUsingBlock:^(Employee *obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"%@---%@---%@",obj.name, obj.height, obj.age);
}];
/*
//查找相关
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name BEGINSWITH %@", @"jack--1"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name ENDSWITH %@",@"4444"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name CONTAINS %@", @"zhang"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name LIKE %@", @"zha*"];
//排序和数量显示
NSSortDescriptor *heightSort = [NSSortDescriptor sortDescriptorWithKey:@"height" ascending:NO];
fetchRequest.sortDescriptors = @[heightSort];
fetchRequest.fetchOffset = 5*i;
fetchRequest.fetchLimit = 5;
*/
- 2.3, 删除数据
- 注意在删除数据后需要重新保存一下才会真正的在数据库中删除
//1, 创建请求
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
request.predicate = [NSPredicate predicateWithFormat:@"name = %@", @"zhangzhang"];
//2,执行请求
NSError *errror;
NSArray *array = [self.context executeFetchRequest:request error:&errror];
//3，解析结果
[array enumerateObjectsUsingBlock:^(Employee *obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"%@---%@---%@", obj.name, obj.age, obj.height);
[self.context deleteObject:obj];
[self.context save:nil];
}];
- 2.4,更新数据
- 更新完之后仍旧需要保存
//1, 创建请求
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
request.predicate = [NSPredicate predicateWithFormat:@"name = %@", @"Jake"];
//2,执行请求
NSError *errror;
NSArray *array = [self.context executeFetchRequest:request error:&errror];
//3，解析结果
[array enumerateObjectsUsingBlock:^(Employee *obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"%@---%@---%@", obj.name, obj.age, obj.height);
obj.name = @"zhangdanfeng";
[self.context updatedObjects];
[self.context save:nil];
}];
3，同一个数据库内表的关联
- 3.1， 创建其他表
Snip20170104_4.png
- 3.2， 在coredata编辑页面进行关联
Snip20170104_5.png
- 3.3， 关联好之后需要重新的创建模型（比如说之前的Employee模型代码文件里面是没有自动生成department信息的， 重新创建会自动生成，当然手写也可以）
Snip20170104_2.png
- 3.4， 直接在代码中创建并赋值即可
Department *department = [NSEntityDescription insertNewObjectForEntityForName:@"Department" inManagedObjectContext:self.context];
department.name = @"ios";
Employee *employee01 = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
employee01.name = [NSString stringWithFormat:@"zhangzhang"];
employee01.height = @(1.59 + arc4random_uniform(6)*0.1);
employee01.age = @(26+arc4random_uniform(4));
//赋值
employee01.department = department;
NSError *errror;
[self.context save:&errror];
if (errror) {
NSLog(@"%@",errror);
}
4，多个数据库简单使用
- 有多个数据库，初始化的时候必须要用方式二进行初始化
//方式二：在有多个数据库的时候会有多个数据库文件夹，所以需要指定特定的数据库文件夹，momd是默认数据库文件夹后缀名，如Company.momd
NSURL *url = [[NSBundle mainBundle] URLForResource:@"Company" withExtension:@"momd"];
NSManagedObjectModel *model = [[NSManagedObjectModel alloc] initWithContentsOfURL:url];
- 一个数据库对应一个上下文，如果有多个数据库，需要创建多个上下文，然后可以独立的进行每个数据库的操作，具体操作方法和上面的一样，只不过换一下上下文即可
