IOS-CoreData（增删改查、表关联、分页和模糊查询、多个数据库）

时间：2023-11-13 23:52:14

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 = @"";

     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 = @"";

     }

     //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 = @"";

     IOSDepart.name = @"IOS";

     IOSDepart.createDate = [NSDate date];

     Department *AndroidDepart = [NSEntityDescription insertNewObjectForEntityForName:@"Department" inManagedObjectContext:self.context];

     AndroidDepart.departNo = @"";

     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 = @"";

     emp1.birthday = [NSDate date];

     emp1.depart = IOSDepart;

     Employee *emp2 = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];

     emp2.name = @"bowen2";

     emp2.height = @"";

     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 = ; i < ; i++) {

         Employee *emp = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];

         emp.name = [NSString stringWithFormat:@"bowen%d",i];

         emp.height = [NSString stringWithFormat:@"%d",+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 = ;

     //分页的条数

     request.fetchLimit = ;

     //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 = @"";

     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

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