新年新气象，曾经的妹子结婚了，而光棍的我决定书写博客~ 废话结束。
本人不爱使用第三方的东东，喜欢原汁原味的官方版本，本次带来CoreData数据存储篇~
创建应用
勾上Use Core Data,不勾也行，后面再添加上去一样的
点击coredata文件，look下
添加实体，点击下面的Add Entity即可，或者通过菜单操作，效果一样。
创建一个实体类
接着，生成代码：
点击Create NSManagedObject Subclass ....,然后选择我们的User，生成代码
写代码之前，先来点介绍吧，主要涉及到下面三个东东
1、Managed Object Model ， 理解成数据库吧，存储了Entity,就是你要存储的东西
2、Persistent Store Coordinate， 理解成数据库连接吧，里面存放了数据存储到具体的文件等等信息
3、Managed Object Context， 数据上下文，基本上所有的操作都是通过这个的。
下面进入写代码状态：
上面三个对象，一个不可少，所以，先来初始化之类的操作吧
1
///
定义三个属性
2
3
4 @property(strong,nonatomic) NSManagedObjectModel *cdModel;
5 @property(strong,nonatomic) NSManagedObjectContext *cdContext;
6 @property(strong,nonatomic) NSPersistentStoreCoordinator *cdCoordinator;
1 - (NSManagedObjectModel *)cdModel
2{
3if(!_cdModel)
4 {
5 _cdModel = [NSManagedObjectModel mergedModelFromBundles:nil];
6 }
7 8return _cdModel;
9}
1011 - (NSPersistentStoreCoordinator *)cdCoordinator
12{
13if(!_cdCoordinator)
14 {
15//find the database16 NSString *dirPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:DBNAME];
17 NSURL *dbPath = [NSURL fileURLWithPath:dirPath];
18 NSError *err;
19 _cdCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.cdModel];
20if(![_cdCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:dbPath options:nil error:&err])
21 {
22 NSLog(@"Error %@ %@",err.localizedDescription,err.localizedFailureReason);
23 }
24 dirPath = nil;
25 dbPath = nil;
26 }
27return _cdCoordinator;
28}
2930 - (NSManagedObjectContext *)cdContext
31{
32if(!_cdContext)
33 {
34 _cdContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
35 [_cdContext setPersistentStoreCoordinator:self.cdCoordinator];
36 }
37return _cdContext;
38 }
下面进行CRUD操作
1 - (void)insertToDB:(NSString *)username password:(NSString *)password
2{
3 User *u = (User *)[NSEntityDescription insertNewObjectForEntityForName:TBNAME inManagedObjectContext:self.cdContext];
4 u.username = username;
5 u.password = password;
6 NSError *err;
7if(![self.cdContext save:&err])
8 {
9 NSLog(@"Error %@ %@",err.localizedDescription,err.localizedFailureReason);
10 }
11}
1213 - (void)readFromDb
14{
15 NSFetchRequest *fetch = [[NSFetchRequest alloc] init];
16 NSEntityDescription *entity = [NSEntityDescription entityForName:TBNAME inManagedObjectContext:self.cdContext];
17 [fetch setEntity:entity];
18 NSError* err;
19 NSArray *results = [self.cdContext executeFetchRequest:fetch error:&err];
20if(err)
21 {
22 NSLog(@"Error %@ %@",err.localizedDescription,err.localizedFailureReason);
23return;
24 }
25 [results enumerateObjectsUsingBlock:^(User *_Nonnull user, NSUInteger idx, BOOL * _Nonnull stop) {
26 NSLog(@"----%@ %@",user.username,user.password);
27 }];
28 }
好的，来测试下：
算了，时间来不及了，要睡觉了，就不啰嗦了，下面是完整代码
1
//
2
//
ViewController.m
3
//
CoreDataTest
4
//
5
//
Created by winter on 16/2/14.
6
//
Copyright ? 2016年 winter. All rights reserved.
7
//
8
9
#import
"
ViewController.h
"
10
#import <CoreData/CoreData.h>
11#import"User.h" 12 13/// define database name 14#define DBNAME @"CoreDataTest.sqlite"
15/// define entity 16#define TBNAME @"User"
17 18 19@interface ViewController ()
20{
21 22}
23///定义三个属性 24 25 26 @property(strong,nonatomic) NSManagedObjectModel *cdModel;
27 @property(strong,nonatomic) NSManagedObjectContext *cdContext;
28 @property(strong,nonatomic) NSPersistentStoreCoordinator *cdCoordinator;
29 30 31@end 32 33@implementation ViewController
34 35#pragma mark - 实现三个属性的getter Method
36 37 - (NSManagedObjectModel *)cdModel
38{
39if(!_cdModel)
40 {
41 _cdModel = [NSManagedObjectModel mergedModelFromBundles:nil];
42 }
43 44return _cdModel;
45}
46 47 - (NSPersistentStoreCoordinator *)cdCoordinator
48{
49if(!_cdCoordinator)
50 {
51//find the database 52 NSString *dirPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:DBNAME];
53 NSURL *dbPath = [NSURL fileURLWithPath:dirPath];
54 NSError *err;
55 _cdCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.cdModel];
56if(![_cdCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:dbPath options:nil error:&err])
57 {
58 NSLog(@"Error %@ %@",err.localizedDescription,err.localizedFailureReason);
59 }
60 dirPath = nil;
61 dbPath = nil;
62 }
63return _cdCoordinator;
64}
65 66 - (NSManagedObjectContext *)cdContext
67{
68if(!_cdContext)
69 {
70 _cdContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
71 [_cdContext setPersistentStoreCoordinator:self.cdCoordinator];
72 }
73return _cdContext;
74}
75 76 77#pragma mark - crud
78 - (void)insertToDB:(NSString *)username password:(NSString *)password
79{
80 User *u = (User *)[NSEntityDescription insertNewObjectForEntityForName:TBNAME inManagedObjectContext:self.cdContext];
81 u.username = username;
82 u.password = password;
83 NSError *err;
84if(![self.cdContext save:&err])
85 {
86 NSLog(@"Error %@ %@",err.localizedDescription,err.localizedFailureReason);
87 }
88}
89 90 - (void)readFromDb
91{
92 NSFetchRequest *fetch = [[NSFetchRequest alloc] init];
93 NSEntityDescription *entity = [NSEntityDescription entityForName:TBNAME inManagedObjectContext:self.cdContext];
94 [fetch setEntity:entity];
95 NSError* err;
96 NSArray *results = [self.cdContext executeFetchRequest:fetch error:&err];
97if(err)
98 {
99 NSLog(@"Error %@ %@",err.localizedDescription,err.localizedFailureReason);
100return;
101 }
102 [results enumerateObjectsUsingBlock:^(User *_Nonnull user, NSUInteger idx, BOOL * _Nonnull stop) {
103 NSLog(@"----%@ %@",user.username,user.password);
104 }];
105}
106107108 - (void)viewDidLoad {
109 [super viewDidLoad];
110// Do any additional setup after loading the view, typically from a nib.111 [self insertToDB:@"wang" password:@"password"];
112113}
114115 - (void)viewDidAppear:(BOOL)animated
116{
117 [super viewDidAppear:animated];
118 [self readFromDb];
119}
120121 - (void)didReceiveMemoryWarning {
122 [super didReceiveMemoryWarning];
123// Dispose of any resources that can be recreated.124}
125126@end
原文：http://www.cnblogs.com/wws19125/p/5189724.html
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