CoreData的表之前的关联

 

Department.h

@interface Department : NSManagedObject

@property (nonatomic, retain) NSString * name;//部门名称
@property (nonatomic, retain) NSString * departNo;//部门的编号
@property (nonatomic, retain) NSDate * createDate;//部门的成立日期

@end

 

Employee.h

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

@class Department;

@interface Employee : NSManagedObject

@property (nonatomic, retain) NSDate * birthday;
@property (nonatomic, retain) NSNumber * height;
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) Department *depart;

@end

 

ViewController.h

#import "ViewController.h"
#import <CoreData/CoreData.h>

#import "Employee.h"
#import "Department.h"

@interface ViewController (){
    NSManagedObjectContext *_context;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
//    1.创建模型文件 ［相当于一个数据库里的表］
//    2.添加实体 ［一张表］
//    3.创建实体类 [相当模型]
//    4.生成上下文 关联模型文件生成数据库
    /*
     * 关联的时候，如果本地没有数据库文件，Ｃoreadata自己会创建
     */
    
    // 上下文
    NSManagedObjectContext *context = [[NSManagedObjectContext alloc] init];
    
    // 上下文关连数据库

    // model模型文件
    NSManagedObjectModel *model = [NSManagedObjectModel mergedModelFromBundles:nil];
    
    // 持久化存储调度器
    // 持久化，把数据保存到一个文件，而不是内存
    NSPersistentStoreCoordinator *store = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
    
    // 告诉Coredata数据库的名字和路径
    NSString *doc = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    
    NSString *sqlitePath = [doc stringByAppendingPathComponent:@"company.sqlite"];
    NSLog(@"%@",sqlitePath);
    [store addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:[NSURL fileURLWithPath:sqlitePath] options:nil error:nil];
    
    context.persistentStoreCoordinator = store;
    _context = context;

}

// 数据库的操作 CURD Create Update  Read Delete
#pragma mark 添加员工
-(IBAction)addEmployee{

    // 创建两个部门 ios android
    Department *iosDepart = [NSEntityDescription insertNewObjectForEntityForName:@"Department" inManagedObjectContext:_context];
    iosDepart.name = @"ios";
    iosDepart.departNo = @"0001";
    iosDepart.createDate = [NSDate date];
    
    Department *andrDepart = [NSEntityDescription insertNewObjectForEntityForName:@"Department" inManagedObjectContext:_context];
    andrDepart.name = @"android";
    andrDepart.departNo = @"0002";
    andrDepart.createDate = [NSDate date];
    
    // 创建两个员工对象 zhangsan属于ios部门 lisi属于android部门
    Employee *zhangsan = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:_context];
    zhangsan.name = @"zhangsan";
    zhangsan.height = @(1.90);
    zhangsan.birthday = [NSDate date];
    zhangsan.depart = iosDepart;
    
    
    Employee *lisi = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:_context];
    lisi.name = @"lisi";
    lisi.height = @2.0;
    lisi.birthday = [NSDate date];
    lisi.depart = andrDepart;
    

    // 直接保存数据库
    NSError *error = nil;
    [_context save:&error];
    
    if (error) {
        NSLog(@"%@",error);
    }
}

#pragma mark 读取员工
-(IBAction)readEmployee{
    
    // 读取ios部门的员工
    
    // 1.FectchRequest 抓取请求对象
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
    
    // 2.设置过滤条件
    NSPredicate *pre = [NSPredicate predicateWithFormat:@"depart.name = %@",@"android"];
    request.predicate = pre;
    
      // 4.执行请求
    NSError *error = nil;
    
    NSArray *emps = [_context executeFetchRequest:request error:&error];
    if (error) {
        NSLog(@"error");
    }
    
    //NSLog(@"%@",emps);
    //遍历员工
    for (Employee *emp in emps) {
        NSLog(@"名字 %@ 部门 %@",emp.name,emp.depart.name);
    }
    
}

#pragma mark 更新员工
-(IBAction)updateEmployee{
    
}

#pragma mark 删除员工
-(IBAction)deleteEmployee{

}
@end