CoreData简单使用

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（1）使用CoreData的时候要先导入CoreData.framework框架

（2）新建Data Model文件，如Person

 (3)在建完Data Model文件后，新建和Data Model相关联的NSManagedObject subclass文件

//
//  ViewController.m
//  zwj-CoreData简单使用
//
//  Created by zwj on 14-10-10.
//  Copyright (c) 2014年 zwj. All rights reserved.
//

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

@interface ViewController (){
    NSManagedObjectContext *_context;
}

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
//    [self addUser:@"xiaoniagua" andAge:@(20)];
//    [self searchUsers];
//    [self deleteUser];
    [self updateUser];
}

/**
 *  删除人员
 */
-(void)deleteUser{
    [self getObjContext];
    NSFetchRequest *fetchReq = [[NSFetchRequest alloc ]initWithEntityName:@"Person"];
    fetchReq.predicate = [NSPredicate predicateWithFormat:@"name =%@",@"zhuweijun"];
    NSLog(@"%@",fetchReq.predicate);
    NSArray *aryUser = [_context executeFetchRequest:fetchReq error:nil];
    NSLog(@"%d",aryUser.count);
    for (Person *p in aryUser) {
        NSLog(@"%@",p.name);
        [_context deleteObject:p];
    }
    [_context save:nil];
}

/**
 *  更新用户信息
 */
-(void)updateUser{
    NSFetchRequest *fetchReq = [[NSFetchRequest alloc ]initWithEntityName:@"Person"];
    fetchReq.predicate = [NSPredicate predicateWithFormat:@"name = %@",@"xiaoniagua"];
    [self getObjContext];
    NSArray *aryUsers =[_context executeFetchRequest:fetchReq error:nil];
    for (Person *p in aryUsers) {
        p.age = @(88);
    }
    // 更新完后要做数据同步
    [_context save:nil];
}

/**
 *  查询人员
 */
-(void) searchUsers{
    [self getObjContext];
    NSFetchRequest *fetchReq = [[NSFetchRequest alloc ]initWithEntityName:@"Person"];
    // 排序
    NSSortDescriptor *sortDes = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:NO];
    fetchReq.sortDescriptors = @[sortDes];
    NSError *searchError = nil;
    NSArray *aryUser = [_context executeFetchRequest:fetchReq error:&searchError];
    for (int i = 0; i < aryUser.count; i++) {
        Person *p = aryUser[i];
        NSLog(@"%@-%@",p.name,p.age);
    }
}

/**
 *  添加人员
 */
-(void)addUser:(NSString *)name andAge:(NSNumber *)age{
    [self getObjContext];
    Person *p = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:_context];
    p.name = name;
    p.age = age;
    NSError *savePersonError = nil;
    [_context save:&savePersonError];
}

/**
 *  持久化存储调度器
 */
-(void)getObjContext{
    // 初始化图形上下文
    NSManagedObjectContext *context = [[NSManagedObjectContext alloc]init];
    
    // 设置持久化存储调度器 NSPersistentStoreCoordinator
    NSString *strPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).lastObject stringByAppendingPathComponent:@"coredata.sqllite"];
    NSLog(@"%@",strPath);
    NSManagedObjectModel *model = [NSManagedObjectModel mergedModelFromBundles:nil];
    NSPersistentStoreCoordinator *coordinator = [[NSPersistentStoreCoordinator alloc ]initWithManagedObjectModel:model];
    NSError *error = nil;
    [coordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:[NSURL fileURLWithPath:strPath] options:nil error:&error];
    context.persistentStoreCoordinator = coordinator;
    _context = context;
}
@end

CoreData简单使用

标签：des   blog   http   io   使用   ar   for   文件   数据   

原文地址：http://www.cnblogs.com/xiaokanfengyu/p/4020466.html