第1步：首先在创建项目的时候必须把Use Core Data 选上
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1.1 新建的工程就会有一个Coredata.xcdatamodeld文件
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1.2如果忘记选User Core Data，还可以另外创建一个.xcdatamodeld文件
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第2步 创建实体
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2.1创建实体关联的操作对象
/注意/
xcode8.0后 自定义的实体关联的操作对象默认swift语言更改
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2.2然后就会生成四个文件
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第3步：新建一个单例 StudentManager
StudentManager.h文件：
#import <Foundation/Foundation.h>
#import "Student+CoreDataProperties.h"
#import "User.h"
@interface StudentManager : NSObject
@property(nonatomic, strong) User *user;
+(id)shareInstance;
//添加数据
#if 0
-(Student *)insertData:(NSDictionary *)stu;
#else
-(Student *)insertData:(User *)user;
#endif
//删除数据
-(BOOL)deleteDataWithName:(NSString *)name;
//查找数据
-(Student *)qureyDataWithName:(NSString *)name;
//改动数据
-(BOOL)upadateDataWithNewData:(User *)newUser OldName:(NSString *)oldName;
//加载整个存储的数据源
-(NSArray *)loadAllData;
@end
StudentManager.m文件：
#import "StudentManager.h"
#import "AppDelegate.h"
@implementation StudentManager
+(id)shareInstance{
static StudentManager *studentManager;
static dispatch_once_t onceTonken;
dispatch_once(&onceTonken, ^{
studentManager = [[StudentManager alloc]init];
});
return studentManager;
}
-(AppDelegate *)delegate{
return (AppDelegate *)[[UIApplication sharedApplication] delegate];
}
#if 0
#pragma mark --- 添加数据 字典形式
-(Student *)insertData:(NSDictionary *)dict{
NSError *error;
NSManagedObjectContext *managerContext = [self delegate].persistentContainer.viewContext;
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Student" inManagedObjectContext:managerContext];
Student *yonger = [(Student *)[NSManagedObject alloc]initWithEntity:entity insertIntoManagedObjectContext:managerContext];
NSLog(@"++++%@",dict);
yonger.name = dict[@"name"];
yonger.age = dict[@"age"] ;
yonger.phone = dict[@"phone"];
BOOL result = [[self delegate].persistentContainer.viewContext save:&error];
if (result) {
return yonger;
}
return nil;
}
#else
-(Student *)insertData:(User *)user{
NSError *error;
NSManagedObjectContext *managerContext = [self delegate].persistentContainer.viewContext;
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Student" inManagedObjectContext:managerContext];
Student *yonger = [(Student *)[NSManagedObject alloc]initWithEntity:entity insertIntoManagedObjectContext:managerContext];
NSLog(@"++++%@",user.name);
yonger.name = user.name;
yonger.age = user.age ;
yonger.phone = user.phone;
BOOL result = [[self delegate].persistentContainer.viewContext save:&error];
if (result) {
return yonger;
}
return nil;
}
#endif
-(NSArray *)loadAllData{
//创建请求
NSFetchRequest *request = [[NSFetchRequest alloc]init];
//设置需要查询的实体对象
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Student" inManagedObjectContext:[self delegate].persistentContainer.viewContext];
//设置请求实体
[request setEntity:entity];
NSError *error = nil;
NSArray *infos = [[[self delegate].persistentContainer.viewContext executeFetchRequest:request error:&error] mutableCopy];
if (!error) {
return infos;
}
return nil;
}
//删除 根据姓名删除
-(BOOL)deleteDataWithName:(NSString *)name{
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name = %@",name];
NSFetchRequest *request = [[NSFetchRequest alloc]init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Student" inManagedObjectContext:[self delegate].persistentContainer.viewContext];
[request setEntity:entity];
[request setPredicate:predicate];
[request setFetchLimit:1];
NSError *error = nil;
NSArray *infos = [[[self delegate].persistentContainer.viewContext executeFetchRequest:request error:&error] mutableCopy];
if (infos == nil) {
return NO;
}
for (Student *stu in infos) {
[[self delegate].persistentContainer.viewContext deleteObject:stu];
[[self delegate].persistentContainer.viewContext save:&error];
}
return NO;
}
//查询
-(Student *)qureyDataWithName:(NSString *)name{
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name = %@",name];
NSFetchRequest *request = [[NSFetchRequest alloc]init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Student" inManagedObjectContext:[self delegate].persistentContainer.viewContext];
[request setEntity:entity];
[request setPredicate:predicate];
[request setFetchLimit:1];
NSError *error = nil;
NSArray *infos = [[[self delegate].persistentContainer.viewContext executeFetchRequest:request error:&error] mutableCopy];
if (infos == nil) {
NSLog(@"查找不到");
return nil;
}
for (Student *stu in infos) {
return stu;
}
return nil;
}
//更新
-(BOOL)upadateDataWithNewData:(User *)newUser OldName:(NSString *)oldName{
NSError *error;
//先查找旧数据
Student *oldstudent = [self qureyDataWithName:oldName];
oldstudent.name = newUser.name;
oldstudent.age = newUser.age;
oldstudent.phone = newUser.phone;
BOOL result = [[self delegate].persistentContainer.viewContext save:&error];
if (result) {
NSLog(@"更新成功");
return YES;
}
NSLog(@"修改不成功");
return NO;
}
@end
注解：添加数据用了两种方法，一种是将要操作的数据属性放在字典中进行传送，一种是用一个数据模型user传送。user模型如下，如果要用字典传送就不需要
user.h
#import <Foundation/Foundation.h>
@interface User : NSObject
@property (nonatomic, copy) NSString *age;
@property (nonatomic, copy) NSString *phone;
@property (nonatomic, copy) NSString *name;
@end
user.m
#import "User.h"
@implementation User
/*
User 可以作为一个数据模型model，如果不用user，我们在保存，查找，删除数据是对数据的传递只能以字典的方式进行，将数据的各个属性挨个保存在dictionary的相应键值中，然后再取出来
user模型 可避免在传递过程中认为的遗漏数据的某个属性，应为user是以一个数据对象的整体来进行传递的
#if X
X=1时执行
#else
X=0时执行
#endif
*/
-(NSString *)name{
if (!_name) {
_name = @"";
}
return _name;
}
-(NSString *)age{
if (!_age) {
_age = @"";
}
return _age;
}
-(NSString *)phone{
if (!_phone) {
_phone = @"";
}
return _phone;
}
@end
