IOS-CoreData（增删改查、表关联、分页和模糊查询、多个数据库）

1>什么是CoreData

Core Data是iOS5之后才出现的一个框架，它提供了对象-关系映射(ORM)的功能，即能够将OC对象转化成数据，保存在SQLite数据库文件中，也能够将保存在数据库中的数据还原成OC对象。在此数据操作期间，我们不需要编写任何SQL语句，这个有点类似于著名的Hibernate持久化框架，不过功能肯定是没有Hibernate强大的。

 

 

 

2>CoreData的使用步骤

 

1.创建模型文件

2.添加实体

3.创建实体类

4.生成上下文 关联模型文件生成数据库

5.保存对象到数据库

6.从数据库获取对象

7.更新数据

8.删除数据

 

3>打开CoreData的SQL语句输出开关

 

1.打开Product，点击EditScheme...

2.点击Arguments，在ArgumentsPassed On Launch中添加2项

   1> -com.apple.CoreData.SQLDebug

   2> 1

 

一、CoreData基本使用-增删改查和表关联

//
//  ViewController.m
//  IOS_0121_CoreData
//
//  Created by ma c on 16/1/21.
//  Copyright © 2016年 博文科技. All rights reserved.
//

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

@interface ViewController ()

@property (nonatomic, strong) NSManagedObjectContext *context;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //1.创建模型文件（相当于数据库中的表）
    //2.添加实体(一张表)
    //3.创建实体类（相当于模型）
    //4.生成上下文，关联模型文件生成数据库
    
    //上下文
    self.context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
    //模型数据文件
    NSManagedObjectModel *model = [NSManagedObjectModel mergedModelFromBundles:nil];
    
    //持久化存储器
    //把数据保存到一个文件，而不是内存
    NSPersistentStoreCoordinator *store = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
    //数据名字和路径
    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *sqlitePath = [path stringByAppendingPathComponent:@"company.sqlite"];
    NSLog(@"%@",sqlitePath);
    
    NSURL *url = [NSURL fileURLWithPath:sqlitePath];
    [store addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:nil];
    
    self.context.persistentStoreCoordinator = store;
    
}
//数据库操作ADUQ （ADD、Delete、Update、Query）
#pragma mark - 添加员工
- (IBAction)addEmployee
{
    Employee *emp = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
    
    emp.name = @"bowen";
    emp.height = @"180";
    emp.birthday = [NSDate date];
    
    
    //直接保存
    NSError *error = nil;
    [self.context save:&error];
    
    if (error) {
        NSLog(@"%@",error);
    }
}

#pragma mark - 查询员工
- (IBAction)searchEmployee
{
    //1.NSFetchRequest 抓取请求对象
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
    //2.设置过滤条件
    NSPredicate *pre = [NSPredicate predicateWithFormat:@"name = %@",@"bowen"];
    request.predicate = pre;
    //3.排序
    NSSortDescriptor *heightSort = [NSSortDescriptor sortDescriptorWithKey:@"height" ascending:YES];
    request.sortDescriptors = @[heightSort];
    //4.执行请求
    NSError *error = nil;
    NSArray *emps = [self.context executeFetchRequest:request error:&error];
    
    if (error) {
        NSLog(@"%@",error);
    }
    
    for (Employee *emp in emps) {
        NSLog(@"name:%@ height:%@ birthday:%@",emp.name, emp.height, emp.birthday);
    }
}

#pragma mark - 更新员工
- (IBAction)updateEmployee
{
    //1.查找
    //获取对象
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
    //设置过滤条件
    NSPredicate *pre = [NSPredicate predicateWithFormat:@"name = %@",@"bowen"];
    request.predicate = pre;
    //执行请求
    NSArray *emps = [self.context executeFetchRequest:request error:nil];
    
    //2.更新
    for (Employee *emp in emps) {
        emp.height = @"200";
    }
    //3.保存
    [self.context save:nil];
}

#pragma mark - 删除员工
- (IBAction)deleteEmployee
{
    //1.查找
    //获取对象
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
    //设置过滤条件
    NSPredicate *pre = [NSPredicate predicateWithFormat:@"name = %@",@"bowen"];
    request.predicate = pre;
    //执行请求
    NSArray *emps = [self.context executeFetchRequest:request error:nil];
    
    //2.删除
    for (Employee *emp in emps) {
        [self.context deleteObject:emp];
    }
    
    //3.保存
    [self.context save:nil];
}

#pragma mark - 表关联
- (IBAction)AddRelationship
{
    //创建两个部门：IOS、Android
    Department *IOSDepart = [NSEntityDescription insertNewObjectForEntityForName:@"Department" inManagedObjectContext:self.context];
    IOSDepart.departNo = @"001";
    IOSDepart.name = @"IOS";
    IOSDepart.createDate = [NSDate date];
    
    Department *AndroidDepart = [NSEntityDescription insertNewObjectForEntityForName:@"Department" inManagedObjectContext:self.context];
    AndroidDepart.departNo = @"002";
    AndroidDepart.name = @"Android";
    AndroidDepart.createDate = [NSDate date];
    
    //创建两个员工：bowen1，bowen2
    Employee *emp1 = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
    emp1.name = @"bowen1";
    emp1.height = @"180";
    emp1.birthday = [NSDate date];
    emp1.depart = IOSDepart;
    
    Employee *emp2 = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
    emp2.name = @"bowen2";
    emp2.height = @"180";
    emp2.birthday = [NSDate date];
    emp2.depart = AndroidDepart;
    
    //保存
    [self.context save:nil];    
}


- (IBAction)searchRelationship
{
    //读取IOS部门员工
    
    //1.NSFetchRequest 抓取请求对象
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
    //2.设置过滤条件
    NSPredicate *pre = [NSPredicate predicateWithFormat:@"depart.name = %@",@"IOS"];
    request.predicate = pre;
    //3.执行请求
    NSError *error = nil;
    NSArray *emps = [self.context executeFetchRequest:request error:&error];
    
    if (error) {
        NSLog(@"%@",error);
    }
    
    for (Employee *emp in emps) {
        NSLog(@"name:%@ height:%@ birthday:%@",emp.name, emp.height, emp.birthday);
    }

}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

 三、分页查询和模糊查询

//
//  ViewController.m
//  IOS_0121_CoreData
//
//  Created by ma c on 16/1/21.
//  Copyright © 2016年 博文科技. All rights reserved.
//

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

@interface ViewController ()

@property (nonatomic, strong) NSManagedObjectContext *context;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //1.创建模型文件（相当于数据库中的表）
    //2.添加实体(一张表)
    //3.创建实体类（相当于模型）
    //4.生成上下文，关联模型文件生成数据库
    
    //上下文
    self.context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
    //模型数据文件
    NSManagedObjectModel *model = [NSManagedObjectModel mergedModelFromBundles:nil];
    
    //持久化存储器
    //把数据保存到一个文件，而不是内存
    NSPersistentStoreCoordinator *store = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
    //数据名字和路径
    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *sqlitePath = [path stringByAppendingPathComponent:@"company.sqlite"];
    NSLog(@"%@",sqlitePath);
    
    NSURL *url = [NSURL fileURLWithPath:sqlitePath];
    [store addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:nil];
    
    self.context.persistentStoreCoordinator = store;
    
}
//数据库操作ADUQ （ADD、Delete、Update、Query）
#pragma mark - 添加员工
- (IBAction)addEmployee
{

    for (int i = 0; i < 15; i++) {
        Employee *emp = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];
        emp.name = [NSString stringWithFormat:@"bowen%d",i];
        emp.height = [NSString stringWithFormat:@"%d",180+i];
        emp.birthday = [NSDate date];
        
    }

    //直接保存
    NSError *error = nil;
    [self.context save:&error];
    
    if (error) {
        NSLog(@"%@",error);
    }
}

#pragma mark - 分页查询
- (IBAction)pagingAndQuerying
{
    //1.NSFetchRequest 抓取请求对象
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
    
    //2.排序
    NSSortDescriptor *heightSort = [NSSortDescriptor sortDescriptorWithKey:@"height" ascending:YES];
    request.sortDescriptors = @[heightSort];
    
    //3.分页查询
    //分页的起始索引
    request.fetchOffset = 12;
    //分页的条数
    request.fetchLimit = 6;
    
    //4.执行请求
    NSError *error = nil;
    NSArray *emps = [self.context executeFetchRequest:request error:&error];
    
    if (error) {
        NSLog(@"%@",error);
    }
    
    for (Employee *emp in emps) {
        NSLog(@"name:%@ height:%@ birthday:%@",emp.name, emp.height, emp.birthday);
    }
}

- (IBAction)fuzzyQuery
{
    //1.NSFetchRequest 抓取请求对象
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];
    
    //2.排序
    NSSortDescriptor *heightSort = [NSSortDescriptor sortDescriptorWithKey:@"height" ascending:YES];
    request.sortDescriptors = @[heightSort];
    
    //3.模糊查询
    //名字以“bowen1”开头
    //NSPredicate *pre = [NSPredicate predicateWithFormat:@"name BEGINSWITH %@",@"bowen1"];
    //request.predicate = pre;
    
    //名字以“1”结尾
    //NSPredicate *pre = [NSPredicate predicateWithFormat:@"name ENDSWITH %@",@"1"];
    //request.predicate = pre;
    
    //名字包含“wen1”结尾
    //NSPredicate *pre = [NSPredicate predicateWithFormat:@"name CONTAINS %@",@"1"];
    //request.predicate = pre;
    
    //like
    //名字以“1”结尾
    //NSPredicate *pre = [NSPredicate predicateWithFormat:@"name like %@",@"*wen14"];
    //request.predicate = pre;
    
    //名字以“bowen2”开头
    NSPredicate *pre = [NSPredicate predicateWithFormat:@"name like %@",@"bowen2*"];
    request.predicate = pre;


    //4.执行请求
    NSError *error = nil;
    NSArray *emps = [self.context executeFetchRequest:request error:&error];
    
    if (error) {
        NSLog(@"%@",error);
    }
    
    for (Employee *emp in emps) {
        NSLog(@"name:%@ height:%@ birthday:%@",emp.name, emp.height, emp.birthday);
    }
}

@end

 三、创建多个数据库

//
//  ViewController.m
//  IOS_0121_CoreData
//
//  Created by ma c on 16/1/21.
//  Copyright © 2016年 博文科技. All rights reserved.
//

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

@interface ViewController ()

@property (nonatomic, strong) NSManagedObjectContext *companyContext;
@property (nonatomic, strong) NSManagedObjectContext *weibocontext;


@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //一个数据库对应着一个上下文
    self.companyContext = [self setupContextWithModelName:@"Company"];
    self.weibocontext = [self setupContextWithModelName:@"weibo"];
    
    
}

//根据模型文件返回上下文
- (NSManagedObjectContext *)setupContextWithModelName:(NSString *)modelName
{
    //1.创建模型文件（相当于数据库中的表）
    //2.添加实体(一张表)
    //3.创建实体类（相当于模型）
    //4.生成上下文，关联模型文件生成数据库
    
    //上下文
    NSManagedObjectContext *context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
    
    //模型数据文件
    //使用下面的方法，如果boundles为空，会把boundles里面所有的模型文件的表都放在一个数据库中
    //NSManagedObjectModel *model = [NSManagedObjectModel mergedModelFromBundles:nil];
    
    NSLog(@"%@",[[NSBundle mainBundle] bundlePath]);
    
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:modelName withExtension:@"momd"];
    NSManagedObjectModel *model = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    
    //持久化存储器
    //把数据保存到一个文件，而不是内存
    NSPersistentStoreCoordinator *store = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
    
    //数据名字和路径
    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    
    NSString *sqlliteName = [NSString stringWithFormat:@"%@.sqllite",modelName];
    
    NSString *sqlitePath = [path stringByAppendingPathComponent:sqlliteName];
    NSLog(@"%@",sqlitePath);
    
    NSURL *url = [NSURL fileURLWithPath:sqlitePath];
    [store addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:nil];
    
    context.persistentStoreCoordinator = store;
    
    return context;

}
//数据库操作ADUQ （ADD、Delete、Update、Query）
#pragma mark - 添加
- (IBAction)add
{
    Employee *emp = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.companyContext];
    emp.name = @"bowen";
    emp.height = @"180";
    emp.birthday = [NSDate date];
    
    Status *status = [NSEntityDescription insertNewObjectForEntityForName:@"Status" inManagedObjectContext:self.weibocontext];
    status.text = @"回家";
    status.createDate = @"2015-01-28";
    
    [self.companyContext save:nil];
    [self.weibocontext save:nil];
    
    
    
    
    

}

#pragma mark - 查询
- (IBAction)querying
{
    
}


@end