在iOS中操作SQLite数据库可以分为以下几步（注意先在项目中导入libsqlite3框架）：
- 打开数据库，利用sqlite3_open()打开数据库会指定一个数据库文件保存路径，如果文件存在则直接打开，否则创建并打开。打开数据库会得到一个sqlite3类型的对象，后面需要借助这个对象进行其他操作。
- 执行SQL语句，执行SQL语句又包括有返回值的语句和无返回值语句。
- 对于无返回值的语句（如增加、删除、修改等）直接通过sqlite3_exec()函数执行；
- 对于有返回值的语句则首先通过sqlite3_prepare_v2()进行sql语句评估（语法检测），然后通过sqlite3_step()依次取出查询结果的每一行数据，对于每行数据都可以通过对应的sqlite3_column_类型()方法获得对应列的数据，如此反复循环直到遍历完成。当然，最后需要释放句柄。
在整个操作过程中无需管理数据库连接，对于嵌入式SQLite操作是持久连接（尽管可以通过sqlite3_close()关闭），不需要开发人员自己释放连接。纵观整个操作过程，其实与其他平台的开发没有明显的区别，较为麻烦的就是数据读取，在iOS平台中使用C进行数据读取采用了游标的形式，每次只能读取一行数据，较为麻烦。因此实际开发中不妨对这些操作进行封装：
KCDbManager.h
//// DbManager.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import #import "KCSingleton.h"@interface KCDbManager : NSObjectsingleton_interface(KCDbManager);#pragma mark - 属性#pragma mark 数据库引用，使用它进行数据库操作@property (nonatomic) sqlite3 *database;#pragma mark - 共有方法/** * 打开数据库 * * @param dbname 数据库名称 */-(void)openDb:(NSString *)dbname;/** * 执行无返回值的sql * * @param sql sql语句 */-(void)executeNonQuery:(NSString *)sql;/** * 执行有返回值的sql * * @param sql sql语句 * * @return 查询结果 */-(NSArray *)executeQuery:(NSString *)sql;@end
KCDbManager.m
//// DbManager.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCDbManager.h"#import#import "KCSingleton.h"#import "KCAppConfig.h"#ifndef kDatabaseName#define kDatabaseName @"myDatabase.db"#endif@interface KCDbManager()@end@implementation KCDbManagersingleton_implementation(KCDbManager)#pragma mark 重写初始化方法-(instancetype)init{ KCDbManager *manager; if((manager=[super init])) { [manager openDb:kDatabaseName]; } return manager;}-(void)openDb:(NSString *)dbname{ //取得数据库保存路径，通常保存沙盒Documents目录 NSString *directory=[NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) firstObject]; NSLog(@"%@",directory); NSString *filePath=[directory stringByAppendingPathComponent:dbname]; //如果有数据库则直接打开，否则创建并打开（注意filePath是ObjC中的字符串，需要转化为C语言字符串类型） if (SQLITE_OK ==sqlite3_open(filePath.UTF8String, &_database)) { NSLog(@"数据库打开成功!"); }else{ NSLog(@"数据库打开失败!"); }}-(void)executeNonQuery:(NSString *)sql{ char *error; //单步执行sql语句，用于插入、修改、删除 if (SQLITE_OK!=sqlite3_exec(_database, sql.UTF8String, NULL, NULL,&error)) { NSLog(@"执行SQL语句过程中发生错误！错误信息：%s",error); }}-(NSArray *)executeQuery:(NSString *)sql{ NSMutableArray *rows=[NSMutableArray array];//数据行 //评估语法正确性 sqlite3_stmt *stmt; //检查语法正确性 if (SQLITE_OK==sqlite3_prepare_v2(_database, sql.UTF8String, -1, &stmt, NULL)) { //单步执行sql语句 while (SQLITE_ROW==sqlite3_step(stmt)) { int columnCount= sqlite3_column_count(stmt); NSMutableDictionary *dic=[NSMutableDictionary dictionary]; for (int i=0; i
在上面的类中对于数据库操作进行了封装，封装之后数据操作更加方便，同时所有的语法都由C转换成了ObjC。
下面仍然以微博查看为例进行SQLite演示。当然实际开发中微博数据是从网络读取的，但是考虑到缓存问题，通常会选择将微博数据保存到本地，下面的Demo演示了将数据存放到本地数据库以及数据读取的过程。当然，实际开发中并不会在视图控制器中直接调用数据库操作方法，在这里通常会引入两个概念Model和Service。Model自不必多说，就是MVC中的模型。而Service指的是操作数据库的服务层，它封装了对于Model的基本操作方法，实现具体的业务逻辑。为了解耦，在控制器中是不会直接接触数据库的，控制器中只和模型（模型是领域的抽象）、服务对象有关系，借助服务层对模型进行各类操作，模型的操作反应到数据库中就是对表中数据的操作。具体关系如下：
要完成上述功能，首先定义一个应用程序全局对象进行数据库、表的创建。为了避免每次都创建数据库和表出错，这里利用了偏好设置进行保存当前创建状态（其实这也是数据存储的一部分），如果创建过了数据库则不再创建，否则创建数据库和表。
KCDatabaseCreator.m
//// KCDatabaseCreator.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCDatabaseCreator.h"#import "KCDbManager.h"@implementation KCDatabaseCreator+(void)initDatabase{ NSString *key=@"IsCreatedDb"; NSUserDefaults *defaults=[[NSUserDefaults alloc]init]; if ([[defaults valueForKey:key] intValue]!=1) { [self createUserTable]; [self createStatusTable]; [defaults setValue:@1 forKey:key]; }}+(void)createUserTable{ NSString *sql=@"CREATE TABLE User (Id integer PRIMARY KEY AUTOINCREMENT,name text,screenName text, profileImageUrl text,mbtype text,city text)"; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}+(void)createStatusTable{ NSString *sql=@"CREATE TABLE Status (Id integer PRIMARY KEY AUTOINCREMENT,source text,createdAt date,\"text\" text,user integer REFERENCES User (Id))"; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}@end 其次，定义数据模型，这里定义用户User和微博Status两个数据模型类。注意模型应该尽量保持其单纯性，仅仅是简单的POCO，不要引入视图、控制器等相关内容。
KCUser.h
//// KCUser.h// UrlConnection//// Created by Kenshin Cui on 14-3-22.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import@interface KCUser : NSObject#pragma mark 编号@property (nonatomic,strong) NSNumber *Id;#pragma mark 用户名@property (nonatomic,copy) NSString *name;#pragma mark 用户昵称@property (nonatomic,copy) NSString *screenName;#pragma mark 头像@property (nonatomic,copy) NSString *profileImageUrl;#pragma mark 会员类型@property (nonatomic,copy) NSString *mbtype;#pragma mark 城市@property (nonatomic,copy) NSString *city;#pragma mark - 动态方法/** * 初始化用户 * * @param name 用户名 * @param city 所在城市 * * @return 用户对象 */-(KCUser *)initWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city;/** * 使用字典初始化用户对象 * * @param dic 用户数据 * * @return 用户对象 */-(KCUser *)initWithDictionary:(NSDictionary *)dic;#pragma mark - 静态方法+(KCUser *)userWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city;@end
KCUser.m
//// KCUser.m// UrlConnection//// Created by Kenshin Cui on 14-3-22.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCUser.h"@implementation KCUser-(KCUser *)initWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city{ if (self=[super init]) { self.name=name; self.screenName=screenName; self.profileImageUrl=profileImageUrl; self.mbtype=mbtype; self.city=city; } return self;}-(KCUser *)initWithDictionary:(NSDictionary *)dic{ if (self=[super init]) { [self setValuesForKeysWithDictionary:dic]; } return self;}+(KCUser *)userWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city{ KCUser *user=[[KCUser alloc]initWithName:name screenName:screenName profileImageUrl:profileImageUrl mbtype:mbtype city:city]; return user;}@end KCStatus.h
//// KCStatus.h// UITableView//// Created by Kenshin Cui on 14-3-1.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCUser.h"@interface KCStatus : NSObject#pragma mark - 属性@property (nonatomic,strong) NSNumber *Id;//微博id@property (nonatomic,strong) KCUser *user;//发送用户@property (nonatomic,copy) NSString *createdAt;//创建时间@property (nonatomic,copy) NSString *source;//设备来源@property (nonatomic,copy) NSString *text;//微博内容#pragma mark - 动态方法/** * 初始化微博数据 * * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param user 发送用户 * * @return 微博对象 */-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user;/** * 初始化微博数据 * * @param profileImageUrl 用户头像 * @param mbtype 会员类型 * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param userId 用户编号 * * @return 微博对象 */-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId;/** * 使用字典初始化微博对象 * * @param dic 字典数据 * * @return 微博对象 */-(KCStatus *)initWithDictionary:(NSDictionary *)dic;#pragma mark - 静态方法/** * 初始化微博数据 * * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param user 发送用户 * * @return 微博对象 */+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user;/** * 初始化微博数据 * * @param profileImageUrl 用户头像 * @param mbtype 会员类型 * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param userId 用户编号 * * @return 微博对象 */+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId;@end
KCStatus.m
//// KCStatus.m// UITableView//// Created by Kenshin Cui on 14-3-1.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCStatus.h"@implementation KCStatus-(KCStatus *)initWithDictionary:(NSDictionary *)dic{ if (self=[super init]) { [self setValuesForKeysWithDictionary:dic]; self.user=[[KCUser alloc]init]; self.user.Id=dic[@"user"]; } return self;}-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user{ if (self=[super init]) { self.createdAt=createAt; self.source=source; self.text=text; self.user=user; } return self;}-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId{ if (self=[super init]) { self.createdAt=createAt; self.source=source; self.text=text; KCUser *user=[[KCUser alloc]init]; user.Id=[NSNumber numberWithInt:userId]; self.user=user; } return self;}-(NSString *)source{ return [NSString stringWithFormat:@"来自 %@",_source];}+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user{ KCStatus *status=[[KCStatus alloc]initWithCreateAt:createAt source:source text:text user:user]; return status;}+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId{ KCStatus *status=[[KCStatus alloc]initWithCreateAt:createAt source:source text:text userId:userId]; return status;}@end 然后，编写服务类，进行数据的增、删、改、查操作，由于服务类方法同样不需要过多的配置，因此定义为单例，保证程序中只有一个实例即可。服务类中调用前面封装的数据库方法将对数据库的操作转换为对模型的操作。
KCUserService.h
//// KCUserService.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCUser.h"#import "KCSingleton.h"@interface KCUserService : NSObjectsingleton_interface(KCUserService)/** * 添加用户信息 * * @param user 用户对象 */-(void)addUser:(KCUser *)user;/** * 删除用户 * * @param user 用户对象 */-(void)removeUser:(KCUser *)user;/** * 根据用户名删除用户 * * @param name 用户名 */-(void)removeUserByName:(NSString *)name;/** * 修改用户内容 * * @param user 用户对象 */-(void)modifyUser:(KCUser *)user;/** * 根据用户编号取得用户 * * @param Id 用户编号 * * @return 用户对象 */-(KCUser *)getUserById:(int)Id;/** * 根据用户名取得用户 * * @param name 用户名 * * @return 用户对象 */-(KCUser *)getUserByName:(NSString *)name;@end
KCUserService.m
//// KCUserService.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCUserService.h"#import "KCUser.h"#import "KCDbManager.h"@implementation KCUserServicesingleton_implementation(KCUserService)-(void)addUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"INSERT INTO User (name,screenName, profileImageUrl,mbtype,city) VALUES('%@','%@','%@','%@','%@')",user.name,user.screenName, user.profileImageUrl,user.mbtype,user.city]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM User WHERE Id='%@'",user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeUserByName:(NSString *)name{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM User WHERE name='%@'",name]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)modifyUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"UPDATE User SET name='%@',screenName='%@',profileImageUrl='%@',mbtype='%@',city='%@' WHERE Id='%@'",user.name,user.screenName,user.profileImageUrl,user.mbtype,user.city,user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(KCUser *)getUserById:(int)Id{ KCUser *user=[[KCUser alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT name,screenName,profileImageUrl,mbtype,city FROM User WHERE Id='%i'", Id]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [user setValuesForKeysWithDictionary:rows[0]]; } return user;}-(KCUser *)getUserByName:(NSString *)name{ KCUser *user=[[KCUser alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT Id, name,screenName,profileImageUrl,mbtype,city FROM User WHERE name='%@'", name]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [user setValuesForKeysWithDictionary:rows[0]]; } return user;}@end KCStatusService.h
//// KCStatusService.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCSingleton.h"@class KCStatus;@interface KCStatusService : NSObjectsingleton_interface(KCStatusService)/** * 添加微博信息 * * @param status 微博对象 */-(void)addStatus:(KCStatus *)status;/** * 删除微博 * * @param status 微博对象 */-(void)removeStatus:(KCStatus *)status;/** * 修改微博内容 * * @param status 微博对象 */-(void)modifyStatus:(KCStatus *)status;/** * 根据编号取得微博 * * @param Id 微博编号 * * @return 微博对象 */-(KCStatus *)getStatusById:(int)Id;/** * 取得所有微博对象 * * @return 所有微博对象 */-(NSArray *)getAllStatus;@end
KCStatusService.m
//// KCStatusService.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCStatusService.h"#import "KCDbManager.h"#import "KCStatus.h"#import "KCUserService.h"#import "KCSingleton.h"@interface KCStatusService(){ }@end@implementation KCStatusServicesingleton_implementation(KCStatusService)-(void)addStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"INSERT INTO Status (source,createdAt,\"text\" ,user) VALUES('%@','%@','%@','%@')",status.source,status.createdAt,status.text,status.user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM Status WHERE Id='%@'",status.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)modifyStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"UPDATE Status SET source='%@',createdAt='%@',\"text\"='%@' ,user='%@' WHERE Id='%@'",status.source,status.createdAt,status.text,status.user, status.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(KCStatus *)getStatusById:(int)Id{ KCStatus *status=[[KCStatus alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT Id, source,createdAt,\"text\" ,user FROM Status WHERE Id='%i'", Id]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [status setValuesForKeysWithDictionary:rows[0]]; status.user=[[KCUserService sharedKCUserService] getUserById:[(NSNumber *)rows[0][@"user"] intValue]] ; } return status;}-(NSArray *)getAllStatus{ NSMutableArray *array=[NSMutableArray array]; NSString *sql=@"SELECT Id, source,createdAt,\"text\" ,user FROM Status ORDER BY Id"; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; for (NSDictionary *dic in rows) { KCStatus *status=[self getStatusById:[(NSNumber *)dic[@"Id"] intValue]]; [array addObject:status]; } return array;}@end 最后，在视图控制器中调用相应的服务层进行各类数据操作，在下面的代码中分别演示了增、删、改、查四类操作。
KCMainViewController.m
//// KCMainTableViewController.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCMainTableViewController.h"#import "KCDbManager.h"#import "KCDatabaseCreator.h"#import "KCUser.h"#import "KCStatus.h"#import "KCUserService.h"#import "KCStatusService.h"#import "KCStatusTableViewCell.h"@interface KCMainTableViewController (){ NSArray *_status; NSMutableArray *_statusCells;}@end@implementation KCMainTableViewController- (void)viewDidLoad { [super viewDidLoad]; [KCDatabaseCreator initDatabase]; // [self addUsers];// [self removeUser];// [self modifyUserInfo]; // [self addStatus]; [self loadStatusData]; }-(void)addUsers{ KCUser *user1=[KCUser userWithName:@"Binger" screenName:@"冰儿" profileImageUrl:@"binger.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user1]; KCUser *user2=[KCUser userWithName:@"Xiaona" screenName:@"小娜" profileImageUrl:@"xiaona.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user2]; KCUser *user3=[KCUser userWithName:@"Lily" screenName:@"丽丽" profileImageUrl:@"lily.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user3]; KCUser *user4=[KCUser userWithName:@"Qianmo" screenName:@"阡陌" profileImageUrl:@"qianmo.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user4]; KCUser *user5=[KCUser userWithName:@"Yanyue" screenName:@"炎月" profileImageUrl:@"yanyue.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user5];}-(void)addStatus{ KCStatus *status1=[KCStatus statusWithCreateAt:@"9:00" source:@"iPhone 6" text:@"一只雪猴在日本边泡温泉边玩iPhone的照片，获得了\"2014年野生动物摄影师\"大赛特等奖。一起来为猴子配个词" userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status1]; KCStatus *status2=[KCStatus statusWithCreateAt:@"9:00" source:@"iPhone 6" text:@"一只雪猴在日本边泡温泉边玩iPhone的照片，获得了\"2014年野生动物摄影师\"大赛特等奖。一起来为猴子配个词" userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status2]; KCStatus *status3=[KCStatus statusWithCreateAt:@"9:30" source:@"iPhone 6" text:@"【我们送iPhone6了 要求很简单】真心回馈粉丝，小编觉得现在最好的奖品就是iPhone6了。今起到12月31日，关注我们，转发微博，就有机会获iPhone6(奖品可能需要等待)！每月抽一台[鼓掌]。不费事，还是试试吧，万一中了呢" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status3]; KCStatus *status4=[KCStatus statusWithCreateAt:@"9:45" source:@"iPhone 6" text:@"重大新闻：蒂姆库克宣布出柜后，ISIS战士怒扔iPhone，沙特神职人员呼吁人们换回iPhone 4。[via Pan-Arabia Enquirer]" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status4]; KCStatus *status5=[KCStatus statusWithCreateAt:@"10:05" source:@"iPhone 6" text:@"小伙伴们，有谁知道怎么往Iphone4S里倒东西？倒入的东西又该在哪里找？用了Iphone这么长时间，还真的不知道怎么弄！有谁知道啊？谢谢！" userId:4]; [[KCStatusService sharedKCStatusService] addStatus:status5]; KCStatus *status6=[KCStatus statusWithCreateAt:@"10:07" source:@"iPhone 6" text:@"在音悦台iPhone客户端里发现一个悦单《Infinite 金明洙》，推荐给大家! " userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status6]; KCStatus *status7=[KCStatus statusWithCreateAt:@"11:20" source:@"iPhone 6" text:@"如果sony吧mp3播放器产品发展下去，不贪图手头节目源的现实利益，就木有苹果的ipod，也就木有iphone。柯达类似的现实利益，不自我革命的案例也是一种巨头的宿命。" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status7]; KCStatus *status8=[KCStatus statusWithCreateAt:@"13:00" source:@"iPhone 6" text:@"【iPhone 7 Plus】新买的iPhone 7 Plus ，如何？够酷炫么？" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status8]; KCStatus *status9=[KCStatus statusWithCreateAt:@"13:24" source:@"iPhone 6" text:@"自拍神器#卡西欧TR500#，tr350S～价格美丽，行货，全国联保～iPhone6 iPhone6Plus卡西欧TR150 TR200 TR350 TR350S全面到货 招收各种代理！[给力]微信：39017366" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status9]; KCStatus *status10=[KCStatus statusWithCreateAt:@"13:26" source:@"iPhone 6" text:@"猜到猴哥玩手机时所思所想者，再奖iPhone一部。（奖品由“2014年野生动物摄影师”评委会颁发）" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status10];}-(void)removeUser{ //注意在SQLite中区分大小写 [[KCUserService sharedKCUserService] removeUserByName:@"Yanyue"];}-(void)modifyUserInfo{ KCUser *user1= [[KCUserService sharedKCUserService]getUserByName:@"Xiaona"]; user1.city=@"上海"; [[KCUserService sharedKCUserService] modifyUser:user1]; KCUser *user2= [[KCUserService sharedKCUserService]getUserByName:@"Lily"]; user2.city=@"深圳"; [[KCUserService sharedKCUserService] modifyUser:user2];}#pragma mark 加载数据-(void)loadStatusData{ _statusCells=[[NSMutableArray alloc]init]; _status=[[KCStatusService sharedKCStatusService]getAllStatus]; [_status enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) { KCStatusTableViewCell *cell=[[KCStatusTableViewCell alloc]init]; cell.status=(KCStatus *)obj; [_statusCells addObject:cell]; }]; NSLog(@"%@",[_status lastObject]);}#pragma mark - Table view data source- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1;}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return _status.count;}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *identtityKey=@"myTableViewCellIdentityKey1"; KCStatusTableViewCell *cell=[self.tableView dequeueReusableCellWithIdentifier:identtityKey]; if(cell==nil){ cell=[[KCStatusTableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:identtityKey]; } cell.status=_status[indexPath.row]; return cell;}-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{ return ((KCStatusTableViewCell *)_statusCells[indexPath.row]).height;}-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section{ return 20.0f;}@end 项目目录结构：
在iOS中操作SQLite数据库可以分为以下几步（注意先在项目中导入libsqlite3框架）：
- 打开数据库，利用sqlite3_open()打开数据库会指定一个数据库文件保存路径，如果文件存在则直接打开，否则创建并打开。打开数据库会得到一个sqlite3类型的对象，后面需要借助这个对象进行其他操作。
- 执行SQL语句，执行SQL语句又包括有返回值的语句和无返回值语句。
- 对于无返回值的语句（如增加、删除、修改等）直接通过sqlite3_exec()函数执行；
- 对于有返回值的语句则首先通过sqlite3_prepare_v2()进行sql语句评估（语法检测），然后通过sqlite3_step()依次取出查询结果的每一行数据，对于每行数据都可以通过对应的sqlite3_column_类型()方法获得对应列的数据，如此反复循环直到遍历完成。当然，最后需要释放句柄。
在整个操作过程中无需管理数据库连接，对于嵌入式SQLite操作是持久连接（尽管可以通过sqlite3_close()关闭），不需要开发人员自己释放连接。纵观整个操作过程，其实与其他平台的开发没有明显的区别，较为麻烦的就是数据读取，在iOS平台中使用C进行数据读取采用了游标的形式，每次只能读取一行数据，较为麻烦。因此实际开发中不妨对这些操作进行封装：
KCDbManager.h
//// DbManager.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import #import "KCSingleton.h"@interface KCDbManager : NSObjectsingleton_interface(KCDbManager);#pragma mark - 属性#pragma mark 数据库引用，使用它进行数据库操作@property (nonatomic) sqlite3 *database;#pragma mark - 共有方法/** * 打开数据库 * * @param dbname 数据库名称 */-(void)openDb:(NSString *)dbname;/** * 执行无返回值的sql * * @param sql sql语句 */-(void)executeNonQuery:(NSString *)sql;/** * 执行有返回值的sql * * @param sql sql语句 * * @return 查询结果 */-(NSArray *)executeQuery:(NSString *)sql;@end
KCDbManager.m
//// DbManager.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCDbManager.h"#import#import "KCSingleton.h"#import "KCAppConfig.h"#ifndef kDatabaseName#define kDatabaseName @"myDatabase.db"#endif@interface KCDbManager()@end@implementation KCDbManagersingleton_implementation(KCDbManager)#pragma mark 重写初始化方法-(instancetype)init{ KCDbManager *manager; if((manager=[super init])) { [manager openDb:kDatabaseName]; } return manager;}-(void)openDb:(NSString *)dbname{ //取得数据库保存路径，通常保存沙盒Documents目录 NSString *directory=[NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) firstObject]; NSLog(@"%@",directory); NSString *filePath=[directory stringByAppendingPathComponent:dbname]; //如果有数据库则直接打开，否则创建并打开（注意filePath是ObjC中的字符串，需要转化为C语言字符串类型） if (SQLITE_OK ==sqlite3_open(filePath.UTF8String, &_database)) { NSLog(@"数据库打开成功!"); }else{ NSLog(@"数据库打开失败!"); }}-(void)executeNonQuery:(NSString *)sql{ char *error; //单步执行sql语句，用于插入、修改、删除 if (SQLITE_OK!=sqlite3_exec(_database, sql.UTF8String, NULL, NULL,&error)) { NSLog(@"执行SQL语句过程中发生错误！错误信息：%s",error); }}-(NSArray *)executeQuery:(NSString *)sql{ NSMutableArray *rows=[NSMutableArray array];//数据行 //评估语法正确性 sqlite3_stmt *stmt; //检查语法正确性 if (SQLITE_OK==sqlite3_prepare_v2(_database, sql.UTF8String, -1, &stmt, NULL)) { //单步执行sql语句 while (SQLITE_ROW==sqlite3_step(stmt)) { int columnCount= sqlite3_column_count(stmt); NSMutableDictionary *dic=[NSMutableDictionary dictionary]; for (int i=0; i
在上面的类中对于数据库操作进行了封装，封装之后数据操作更加方便，同时所有的语法都由C转换成了ObjC。
下面仍然以微博查看为例进行SQLite演示。当然实际开发中微博数据是从网络读取的，但是考虑到缓存问题，通常会选择将微博数据保存到本地，下面的Demo演示了将数据存放到本地数据库以及数据读取的过程。当然，实际开发中并不会在视图控制器中直接调用数据库操作方法，在这里通常会引入两个概念Model和Service。Model自不必多说，就是MVC中的模型。而Service指的是操作数据库的服务层，它封装了对于Model的基本操作方法，实现具体的业务逻辑。为了解耦，在控制器中是不会直接接触数据库的，控制器中只和模型（模型是领域的抽象）、服务对象有关系，借助服务层对模型进行各类操作，模型的操作反应到数据库中就是对表中数据的操作。具体关系如下：
要完成上述功能，首先定义一个应用程序全局对象进行数据库、表的创建。为了避免每次都创建数据库和表出错，这里利用了偏好设置进行保存当前创建状态（其实这也是数据存储的一部分），如果创建过了数据库则不再创建，否则创建数据库和表。
KCDatabaseCreator.m
//// KCDatabaseCreator.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCDatabaseCreator.h"#import "KCDbManager.h"@implementation KCDatabaseCreator+(void)initDatabase{ NSString *key=@"IsCreatedDb"; NSUserDefaults *defaults=[[NSUserDefaults alloc]init]; if ([[defaults valueForKey:key] intValue]!=1) { [self createUserTable]; [self createStatusTable]; [defaults setValue:@1 forKey:key]; }}+(void)createUserTable{ NSString *sql=@"CREATE TABLE User (Id integer PRIMARY KEY AUTOINCREMENT,name text,screenName text, profileImageUrl text,mbtype text,city text)"; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}+(void)createStatusTable{ NSString *sql=@"CREATE TABLE Status (Id integer PRIMARY KEY AUTOINCREMENT,source text,createdAt date,\"text\" text,user integer REFERENCES User (Id))"; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}@end 其次，定义数据模型，这里定义用户User和微博Status两个数据模型类。注意模型应该尽量保持其单纯性，仅仅是简单的POCO，不要引入视图、控制器等相关内容。
KCUser.h
//// KCUser.h// UrlConnection//// Created by Kenshin Cui on 14-3-22.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import@interface KCUser : NSObject#pragma mark 编号@property (nonatomic,strong) NSNumber *Id;#pragma mark 用户名@property (nonatomic,copy) NSString *name;#pragma mark 用户昵称@property (nonatomic,copy) NSString *screenName;#pragma mark 头像@property (nonatomic,copy) NSString *profileImageUrl;#pragma mark 会员类型@property (nonatomic,copy) NSString *mbtype;#pragma mark 城市@property (nonatomic,copy) NSString *city;#pragma mark - 动态方法/** * 初始化用户 * * @param name 用户名 * @param city 所在城市 * * @return 用户对象 */-(KCUser *)initWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city;/** * 使用字典初始化用户对象 * * @param dic 用户数据 * * @return 用户对象 */-(KCUser *)initWithDictionary:(NSDictionary *)dic;#pragma mark - 静态方法+(KCUser *)userWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city;@end
KCUser.m
//// KCUser.m// UrlConnection//// Created by Kenshin Cui on 14-3-22.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCUser.h"@implementation KCUser-(KCUser *)initWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city{ if (self=[super init]) { self.name=name; self.screenName=screenName; self.profileImageUrl=profileImageUrl; self.mbtype=mbtype; self.city=city; } return self;}-(KCUser *)initWithDictionary:(NSDictionary *)dic{ if (self=[super init]) { [self setValuesForKeysWithDictionary:dic]; } return self;}+(KCUser *)userWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city{ KCUser *user=[[KCUser alloc]initWithName:name screenName:screenName profileImageUrl:profileImageUrl mbtype:mbtype city:city]; return user;}@end KCStatus.h
//// KCStatus.h// UITableView//// Created by Kenshin Cui on 14-3-1.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCUser.h"@interface KCStatus : NSObject#pragma mark - 属性@property (nonatomic,strong) NSNumber *Id;//微博id@property (nonatomic,strong) KCUser *user;//发送用户@property (nonatomic,copy) NSString *createdAt;//创建时间@property (nonatomic,copy) NSString *source;//设备来源@property (nonatomic,copy) NSString *text;//微博内容#pragma mark - 动态方法/** * 初始化微博数据 * * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param user 发送用户 * * @return 微博对象 */-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user;/** * 初始化微博数据 * * @param profileImageUrl 用户头像 * @param mbtype 会员类型 * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param userId 用户编号 * * @return 微博对象 */-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId;/** * 使用字典初始化微博对象 * * @param dic 字典数据 * * @return 微博对象 */-(KCStatus *)initWithDictionary:(NSDictionary *)dic;#pragma mark - 静态方法/** * 初始化微博数据 * * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param user 发送用户 * * @return 微博对象 */+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user;/** * 初始化微博数据 * * @param profileImageUrl 用户头像 * @param mbtype 会员类型 * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param userId 用户编号 * * @return 微博对象 */+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId;@end
KCStatus.m
//// KCStatus.m// UITableView//// Created by Kenshin Cui on 14-3-1.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCStatus.h"@implementation KCStatus-(KCStatus *)initWithDictionary:(NSDictionary *)dic{ if (self=[super init]) { [self setValuesForKeysWithDictionary:dic]; self.user=[[KCUser alloc]init]; self.user.Id=dic[@"user"]; } return self;}-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user{ if (self=[super init]) { self.createdAt=createAt; self.source=source; self.text=text; self.user=user; } return self;}-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId{ if (self=[super init]) { self.createdAt=createAt; self.source=source; self.text=text; KCUser *user=[[KCUser alloc]init]; user.Id=[NSNumber numberWithInt:userId]; self.user=user; } return self;}-(NSString *)source{ return [NSString stringWithFormat:@"来自 %@",_source];}+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user{ KCStatus *status=[[KCStatus alloc]initWithCreateAt:createAt source:source text:text user:user]; return status;}+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId{ KCStatus *status=[[KCStatus alloc]initWithCreateAt:createAt source:source text:text userId:userId]; return status;}@end 然后，编写服务类，进行数据的增、删、改、查操作，由于服务类方法同样不需要过多的配置，因此定义为单例，保证程序中只有一个实例即可。服务类中调用前面封装的数据库方法将对数据库的操作转换为对模型的操作。
KCUserService.h
//// KCUserService.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCUser.h"#import "KCSingleton.h"@interface KCUserService : NSObjectsingleton_interface(KCUserService)/** * 添加用户信息 * * @param user 用户对象 */-(void)addUser:(KCUser *)user;/** * 删除用户 * * @param user 用户对象 */-(void)removeUser:(KCUser *)user;/** * 根据用户名删除用户 * * @param name 用户名 */-(void)removeUserByName:(NSString *)name;/** * 修改用户内容 * * @param user 用户对象 */-(void)modifyUser:(KCUser *)user;/** * 根据用户编号取得用户 * * @param Id 用户编号 * * @return 用户对象 */-(KCUser *)getUserById:(int)Id;/** * 根据用户名取得用户 * * @param name 用户名 * * @return 用户对象 */-(KCUser *)getUserByName:(NSString *)name;@end
KCUserService.m
//// KCUserService.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCUserService.h"#import "KCUser.h"#import "KCDbManager.h"@implementation KCUserServicesingleton_implementation(KCUserService)-(void)addUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"INSERT INTO User (name,screenName, profileImageUrl,mbtype,city) VALUES('%@','%@','%@','%@','%@')",user.name,user.screenName, user.profileImageUrl,user.mbtype,user.city]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM User WHERE Id='%@'",user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeUserByName:(NSString *)name{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM User WHERE name='%@'",name]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)modifyUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"UPDATE User SET name='%@',screenName='%@',profileImageUrl='%@',mbtype='%@',city='%@' WHERE Id='%@'",user.name,user.screenName,user.profileImageUrl,user.mbtype,user.city,user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(KCUser *)getUserById:(int)Id{ KCUser *user=[[KCUser alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT name,screenName,profileImageUrl,mbtype,city FROM User WHERE Id='%i'", Id]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [user setValuesForKeysWithDictionary:rows[0]]; } return user;}-(KCUser *)getUserByName:(NSString *)name{ KCUser *user=[[KCUser alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT Id, name,screenName,profileImageUrl,mbtype,city FROM User WHERE name='%@'", name]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [user setValuesForKeysWithDictionary:rows[0]]; } return user;}@end KCStatusService.h
//// KCStatusService.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCSingleton.h"@class KCStatus;@interface KCStatusService : NSObjectsingleton_interface(KCStatusService)/** * 添加微博信息 * * @param status 微博对象 */-(void)addStatus:(KCStatus *)status;/** * 删除微博 * * @param status 微博对象 */-(void)removeStatus:(KCStatus *)status;/** * 修改微博内容 * * @param status 微博对象 */-(void)modifyStatus:(KCStatus *)status;/** * 根据编号取得微博 * * @param Id 微博编号 * * @return 微博对象 */-(KCStatus *)getStatusById:(int)Id;/** * 取得所有微博对象 * * @return 所有微博对象 */-(NSArray *)getAllStatus;@end
KCStatusService.m
//// KCStatusService.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCStatusService.h"#import "KCDbManager.h"#import "KCStatus.h"#import "KCUserService.h"#import "KCSingleton.h"@interface KCStatusService(){ }@end@implementation KCStatusServicesingleton_implementation(KCStatusService)-(void)addStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"INSERT INTO Status (source,createdAt,\"text\" ,user) VALUES('%@','%@','%@','%@')",status.source,status.createdAt,status.text,status.user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM Status WHERE Id='%@'",status.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)modifyStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"UPDATE Status SET source='%@',createdAt='%@',\"text\"='%@' ,user='%@' WHERE Id='%@'",status.source,status.createdAt,status.text,status.user, status.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(KCStatus *)getStatusById:(int)Id{ KCStatus *status=[[KCStatus alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT Id, source,createdAt,\"text\" ,user FROM Status WHERE Id='%i'", Id]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [status setValuesForKeysWithDictionary:rows[0]]; status.user=[[KCUserService sharedKCUserService] getUserById:[(NSNumber *)rows[0][@"user"] intValue]] ; } return status;}-(NSArray *)getAllStatus{ NSMutableArray *array=[NSMutableArray array]; NSString *sql=@"SELECT Id, source,createdAt,\"text\" ,user FROM Status ORDER BY Id"; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; for (NSDictionary *dic in rows) { KCStatus *status=[self getStatusById:[(NSNumber *)dic[@"Id"] intValue]]; [array addObject:status]; } return array;}@end 最后，在视图控制器中调用相应的服务层进行各类数据操作，在下面的代码中分别演示了增、删、改、查四类操作。
KCMainViewController.m
//// KCMainTableViewController.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCMainTableViewController.h"#import "KCDbManager.h"#import "KCDatabaseCreator.h"#import "KCUser.h"#import "KCStatus.h"#import "KCUserService.h"#import "KCStatusService.h"#import "KCStatusTableViewCell.h"@interface KCMainTableViewController (){ NSArray *_status; NSMutableArray *_statusCells;}@end@implementation KCMainTableViewController- (void)viewDidLoad { [super viewDidLoad]; [KCDatabaseCreator initDatabase]; // [self addUsers];// [self removeUser];// [self modifyUserInfo]; // [self addStatus]; [self loadStatusData]; }-(void)addUsers{ KCUser *user1=[KCUser userWithName:@"Binger" screenName:@"冰儿" profileImageUrl:@"binger.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user1]; KCUser *user2=[KCUser userWithName:@"Xiaona" screenName:@"小娜" profileImageUrl:@"xiaona.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user2]; KCUser *user3=[KCUser userWithName:@"Lily" screenName:@"丽丽" profileImageUrl:@"lily.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user3]; KCUser *user4=[KCUser userWithName:@"Qianmo" screenName:@"阡陌" profileImageUrl:@"qianmo.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user4]; KCUser *user5=[KCUser userWithName:@"Yanyue" screenName:@"炎月" profileImageUrl:@"yanyue.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user5];}-(void)addStatus{ KCStatus *status1=[KCStatus statusWithCreateAt:@"9:00" source:@"iPhone 6" text:@"一只雪猴在日本边泡温泉边玩iPhone的照片，获得了\"2014年野生动物摄影师\"大赛特等奖。一起来为猴子配个词" userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status1]; KCStatus *status2=[KCStatus statusWithCreateAt:@"9:00" source:@"iPhone 6" text:@"一只雪猴在日本边泡温泉边玩iPhone的照片，获得了\"2014年野生动物摄影师\"大赛特等奖。一起来为猴子配个词" userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status2]; KCStatus *status3=[KCStatus statusWithCreateAt:@"9:30" source:@"iPhone 6" text:@"【我们送iPhone6了 要求很简单】真心回馈粉丝，小编觉得现在最好的奖品就是iPhone6了。今起到12月31日，关注我们，转发微博，就有机会获iPhone6(奖品可能需要等待)！每月抽一台[鼓掌]。不费事，还是试试吧，万一中了呢" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status3]; KCStatus *status4=[KCStatus statusWithCreateAt:@"9:45" source:@"iPhone 6" text:@"重大新闻：蒂姆库克宣布出柜后，ISIS战士怒扔iPhone，沙特神职人员呼吁人们换回iPhone 4。[via Pan-Arabia Enquirer]" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status4]; KCStatus *status5=[KCStatus statusWithCreateAt:@"10:05" source:@"iPhone 6" text:@"小伙伴们，有谁知道怎么往Iphone4S里倒东西？倒入的东西又该在哪里找？用了Iphone这么长时间，还真的不知道怎么弄！有谁知道啊？谢谢！" userId:4]; [[KCStatusService sharedKCStatusService] addStatus:status5]; KCStatus *status6=[KCStatus statusWithCreateAt:@"10:07" source:@"iPhone 6" text:@"在音悦台iPhone客户端里发现一个悦单《Infinite 金明洙》，推荐给大家! " userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status6]; KCStatus *status7=[KCStatus statusWithCreateAt:@"11:20" source:@"iPhone 6" text:@"如果sony吧mp3播放器产品发展下去，不贪图手头节目源的现实利益，就木有苹果的ipod，也就木有iphone。柯达类似的现实利益，不自我革命的案例也是一种巨头的宿命。" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status7]; KCStatus *status8=[KCStatus statusWithCreateAt:@"13:00" source:@"iPhone 6" text:@"【iPhone 7 Plus】新买的iPhone 7 Plus ，如何？够酷炫么？" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status8]; KCStatus *status9=[KCStatus statusWithCreateAt:@"13:24" source:@"iPhone 6" text:@"自拍神器#卡西欧TR500#，tr350S～价格美丽，行货，全国联保～iPhone6 iPhone6Plus卡西欧TR150 TR200 TR350 TR350S全面到货 招收各种代理！[给力]微信：39017366" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status9]; KCStatus *status10=[KCStatus statusWithCreateAt:@"13:26" source:@"iPhone 6" text:@"猜到猴哥玩手机时所思所想者，再奖iPhone一部。（奖品由“2014年野生动物摄影师”评委会颁发）" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status10];}-(void)removeUser{ //注意在SQLite中区分大小写 [[KCUserService sharedKCUserService] removeUserByName:@"Yanyue"];}-(void)modifyUserInfo{ KCUser *user1= [[KCUserService sharedKCUserService]getUserByName:@"Xiaona"]; user1.city=@"上海"; [[KCUserService sharedKCUserService] modifyUser:user1]; KCUser *user2= [[KCUserService sharedKCUserService]getUserByName:@"Lily"]; user2.city=@"深圳"; [[KCUserService sharedKCUserService] modifyUser:user2];}#pragma mark 加载数据-(void)loadStatusData{ _statusCells=[[NSMutableArray alloc]init]; _status=[[KCStatusService sharedKCStatusService]getAllStatus]; [_status enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) { KCStatusTableViewCell *cell=[[KCStatusTableViewCell alloc]init]; cell.status=(KCStatus *)obj; [_statusCells addObject:cell]; }]; NSLog(@"%@",[_status lastObject]);}#pragma mark - Table view data source- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1;}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return _status.count;}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *identtityKey=@"myTableViewCellIdentityKey1"; KCStatusTableViewCell *cell=[self.tableView dequeueReusableCellWithIdentifier:identtityKey]; if(cell==nil){ cell=[[KCStatusTableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:identtityKey]; } cell.status=_status[indexPath.row]; return cell;}-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{ return ((KCStatusTableViewCell *)_statusCells[indexPath.row]).height;}-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section{ return 20.0f;}@end 项目目录结构：
在iOS中操作SQLite数据库可以分为以下几步（注意先在项目中导入libsqlite3框架）：
- 打开数据库，利用sqlite3_open()打开数据库会指定一个数据库文件保存路径，如果文件存在则直接打开，否则创建并打开。打开数据库会得到一个sqlite3类型的对象，后面需要借助这个对象进行其他操作。
- 执行SQL语句，执行SQL语句又包括有返回值的语句和无返回值语句。
- 对于无返回值的语句（如增加、删除、修改等）直接通过sqlite3_exec()函数执行；
- 对于有返回值的语句则首先通过sqlite3_prepare_v2()进行sql语句评估（语法检测），然后通过sqlite3_step()依次取出查询结果的每一行数据，对于每行数据都可以通过对应的sqlite3_column_类型()方法获得对应列的数据，如此反复循环直到遍历完成。当然，最后需要释放句柄。
在整个操作过程中无需管理数据库连接，对于嵌入式SQLite操作是持久连接（尽管可以通过sqlite3_close()关闭），不需要开发人员自己释放连接。纵观整个操作过程，其实与其他平台的开发没有明显的区别，较为麻烦的就是数据读取，在iOS平台中使用C进行数据读取采用了游标的形式，每次只能读取一行数据，较为麻烦。因此实际开发中不妨对这些操作进行封装：
KCDbManager.h
//// DbManager.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import #import "KCSingleton.h"@interface KCDbManager : NSObjectsingleton_interface(KCDbManager);#pragma mark - 属性#pragma mark 数据库引用，使用它进行数据库操作@property (nonatomic) sqlite3 *database;#pragma mark - 共有方法/** * 打开数据库 * * @param dbname 数据库名称 */-(void)openDb:(NSString *)dbname;/** * 执行无返回值的sql * * @param sql sql语句 */-(void)executeNonQuery:(NSString *)sql;/** * 执行有返回值的sql * * @param sql sql语句 * * @return 查询结果 */-(NSArray *)executeQuery:(NSString *)sql;@end
KCDbManager.m
//// DbManager.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCDbManager.h"#import#import "KCSingleton.h"#import "KCAppConfig.h"#ifndef kDatabaseName#define kDatabaseName @"myDatabase.db"#endif@interface KCDbManager()@end@implementation KCDbManagersingleton_implementation(KCDbManager)#pragma mark 重写初始化方法-(instancetype)init{ KCDbManager *manager; if((manager=[super init])) { [manager openDb:kDatabaseName]; } return manager;}-(void)openDb:(NSString *)dbname{ //取得数据库保存路径，通常保存沙盒Documents目录 NSString *directory=[NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) firstObject]; NSLog(@"%@",directory); NSString *filePath=[directory stringByAppendingPathComponent:dbname]; //如果有数据库则直接打开，否则创建并打开（注意filePath是ObjC中的字符串，需要转化为C语言字符串类型） if (SQLITE_OK ==sqlite3_open(filePath.UTF8String, &_database)) { NSLog(@"数据库打开成功!"); }else{ NSLog(@"数据库打开失败!"); }}-(void)executeNonQuery:(NSString *)sql{ char *error; //单步执行sql语句，用于插入、修改、删除 if (SQLITE_OK!=sqlite3_exec(_database, sql.UTF8String, NULL, NULL,&error)) { NSLog(@"执行SQL语句过程中发生错误！错误信息：%s",error); }}-(NSArray *)executeQuery:(NSString *)sql{ NSMutableArray *rows=[NSMutableArray array];//数据行 //评估语法正确性 sqlite3_stmt *stmt; //检查语法正确性 if (SQLITE_OK==sqlite3_prepare_v2(_database, sql.UTF8String, -1, &stmt, NULL)) { //单步执行sql语句 while (SQLITE_ROW==sqlite3_step(stmt)) { int columnCount= sqlite3_column_count(stmt); NSMutableDictionary *dic=[NSMutableDictionary dictionary]; for (int i=0; i
在上面的类中对于数据库操作进行了封装，封装之后数据操作更加方便，同时所有的语法都由C转换成了ObjC。
下面仍然以微博查看为例进行SQLite演示。当然实际开发中微博数据是从网络读取的，但是考虑到缓存问题，通常会选择将微博数据保存到本地，下面的Demo演示了将数据存放到本地数据库以及数据读取的过程。当然，实际开发中并不会在视图控制器中直接调用数据库操作方法，在这里通常会引入两个概念Model和Service。Model自不必多说，就是MVC中的模型。而Service指的是操作数据库的服务层，它封装了对于Model的基本操作方法，实现具体的业务逻辑。为了解耦，在控制器中是不会直接接触数据库的，控制器中只和模型（模型是领域的抽象）、服务对象有关系，借助服务层对模型进行各类操作，模型的操作反应到数据库中就是对表中数据的操作。具体关系如下：
要完成上述功能，首先定义一个应用程序全局对象进行数据库、表的创建。为了避免每次都创建数据库和表出错，这里利用了偏好设置进行保存当前创建状态（其实这也是数据存储的一部分），如果创建过了数据库则不再创建，否则创建数据库和表。
KCDatabaseCreator.m
//// KCDatabaseCreator.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCDatabaseCreator.h"#import "KCDbManager.h"@implementation KCDatabaseCreator+(void)initDatabase{ NSString *key=@"IsCreatedDb"; NSUserDefaults *defaults=[[NSUserDefaults alloc]init]; if ([[defaults valueForKey:key] intValue]!=1) { [self createUserTable]; [self createStatusTable]; [defaults setValue:@1 forKey:key]; }}+(void)createUserTable{ NSString *sql=@"CREATE TABLE User (Id integer PRIMARY KEY AUTOINCREMENT,name text,screenName text, profileImageUrl text,mbtype text,city text)"; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}+(void)createStatusTable{ NSString *sql=@"CREATE TABLE Status (Id integer PRIMARY KEY AUTOINCREMENT,source text,createdAt date,\"text\" text,user integer REFERENCES User (Id))"; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}@end 其次，定义数据模型，这里定义用户User和微博Status两个数据模型类。注意模型应该尽量保持其单纯性，仅仅是简单的POCO，不要引入视图、控制器等相关内容。
KCUser.h
//// KCUser.h// UrlConnection//// Created by Kenshin Cui on 14-3-22.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import@interface KCUser : NSObject#pragma mark 编号@property (nonatomic,strong) NSNumber *Id;#pragma mark 用户名@property (nonatomic,copy) NSString *name;#pragma mark 用户昵称@property (nonatomic,copy) NSString *screenName;#pragma mark 头像@property (nonatomic,copy) NSString *profileImageUrl;#pragma mark 会员类型@property (nonatomic,copy) NSString *mbtype;#pragma mark 城市@property (nonatomic,copy) NSString *city;#pragma mark - 动态方法/** * 初始化用户 * * @param name 用户名 * @param city 所在城市 * * @return 用户对象 */-(KCUser *)initWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city;/** * 使用字典初始化用户对象 * * @param dic 用户数据 * * @return 用户对象 */-(KCUser *)initWithDictionary:(NSDictionary *)dic;#pragma mark - 静态方法+(KCUser *)userWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city;@end
KCUser.m
//// KCUser.m// UrlConnection//// Created by Kenshin Cui on 14-3-22.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCUser.h"@implementation KCUser-(KCUser *)initWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city{ if (self=[super init]) { self.name=name; self.screenName=screenName; self.profileImageUrl=profileImageUrl; self.mbtype=mbtype; self.city=city; } return self;}-(KCUser *)initWithDictionary:(NSDictionary *)dic{ if (self=[super init]) { [self setValuesForKeysWithDictionary:dic]; } return self;}+(KCUser *)userWithName:(NSString *)name screenName:(NSString *)screenName profileImageUrl:(NSString *)profileImageUrl mbtype:(NSString *)mbtype city:(NSString *)city{ KCUser *user=[[KCUser alloc]initWithName:name screenName:screenName profileImageUrl:profileImageUrl mbtype:mbtype city:city]; return user;}@end KCStatus.h
//// KCStatus.h// UITableView//// Created by Kenshin Cui on 14-3-1.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCUser.h"@interface KCStatus : NSObject#pragma mark - 属性@property (nonatomic,strong) NSNumber *Id;//微博id@property (nonatomic,strong) KCUser *user;//发送用户@property (nonatomic,copy) NSString *createdAt;//创建时间@property (nonatomic,copy) NSString *source;//设备来源@property (nonatomic,copy) NSString *text;//微博内容#pragma mark - 动态方法/** * 初始化微博数据 * * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param user 发送用户 * * @return 微博对象 */-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user;/** * 初始化微博数据 * * @param profileImageUrl 用户头像 * @param mbtype 会员类型 * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param userId 用户编号 * * @return 微博对象 */-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId;/** * 使用字典初始化微博对象 * * @param dic 字典数据 * * @return 微博对象 */-(KCStatus *)initWithDictionary:(NSDictionary *)dic;#pragma mark - 静态方法/** * 初始化微博数据 * * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param user 发送用户 * * @return 微博对象 */+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user;/** * 初始化微博数据 * * @param profileImageUrl 用户头像 * @param mbtype 会员类型 * @param createAt 创建日期 * @param source 来源 * @param text 微博内容 * @param userId 用户编号 * * @return 微博对象 */+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId;@end
KCStatus.m
//// KCStatus.m// UITableView//// Created by Kenshin Cui on 14-3-1.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCStatus.h"@implementation KCStatus-(KCStatus *)initWithDictionary:(NSDictionary *)dic{ if (self=[super init]) { [self setValuesForKeysWithDictionary:dic]; self.user=[[KCUser alloc]init]; self.user.Id=dic[@"user"]; } return self;}-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user{ if (self=[super init]) { self.createdAt=createAt; self.source=source; self.text=text; self.user=user; } return self;}-(KCStatus *)initWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId{ if (self=[super init]) { self.createdAt=createAt; self.source=source; self.text=text; KCUser *user=[[KCUser alloc]init]; user.Id=[NSNumber numberWithInt:userId]; self.user=user; } return self;}-(NSString *)source{ return [NSString stringWithFormat:@"来自 %@",_source];}+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text user:(KCUser *)user{ KCStatus *status=[[KCStatus alloc]initWithCreateAt:createAt source:source text:text user:user]; return status;}+(KCStatus *)statusWithCreateAt:(NSString *)createAt source:(NSString *)source text:(NSString *)text userId:(int)userId{ KCStatus *status=[[KCStatus alloc]initWithCreateAt:createAt source:source text:text userId:userId]; return status;}@end 然后，编写服务类，进行数据的增、删、改、查操作，由于服务类方法同样不需要过多的配置，因此定义为单例，保证程序中只有一个实例即可。服务类中调用前面封装的数据库方法将对数据库的操作转换为对模型的操作。
KCUserService.h
//// KCUserService.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCUser.h"#import "KCSingleton.h"@interface KCUserService : NSObjectsingleton_interface(KCUserService)/** * 添加用户信息 * * @param user 用户对象 */-(void)addUser:(KCUser *)user;/** * 删除用户 * * @param user 用户对象 */-(void)removeUser:(KCUser *)user;/** * 根据用户名删除用户 * * @param name 用户名 */-(void)removeUserByName:(NSString *)name;/** * 修改用户内容 * * @param user 用户对象 */-(void)modifyUser:(KCUser *)user;/** * 根据用户编号取得用户 * * @param Id 用户编号 * * @return 用户对象 */-(KCUser *)getUserById:(int)Id;/** * 根据用户名取得用户 * * @param name 用户名 * * @return 用户对象 */-(KCUser *)getUserByName:(NSString *)name;@end
KCUserService.m
//// KCUserService.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCUserService.h"#import "KCUser.h"#import "KCDbManager.h"@implementation KCUserServicesingleton_implementation(KCUserService)-(void)addUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"INSERT INTO User (name,screenName, profileImageUrl,mbtype,city) VALUES('%@','%@','%@','%@','%@')",user.name,user.screenName, user.profileImageUrl,user.mbtype,user.city]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM User WHERE Id='%@'",user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeUserByName:(NSString *)name{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM User WHERE name='%@'",name]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)modifyUser:(KCUser *)user{ NSString *sql=[NSString stringWithFormat:@"UPDATE User SET name='%@',screenName='%@',profileImageUrl='%@',mbtype='%@',city='%@' WHERE Id='%@'",user.name,user.screenName,user.profileImageUrl,user.mbtype,user.city,user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(KCUser *)getUserById:(int)Id{ KCUser *user=[[KCUser alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT name,screenName,profileImageUrl,mbtype,city FROM User WHERE Id='%i'", Id]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [user setValuesForKeysWithDictionary:rows[0]]; } return user;}-(KCUser *)getUserByName:(NSString *)name{ KCUser *user=[[KCUser alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT Id, name,screenName,profileImageUrl,mbtype,city FROM User WHERE name='%@'", name]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [user setValuesForKeysWithDictionary:rows[0]]; } return user;}@end KCStatusService.h
//// KCStatusService.h// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import#import "KCSingleton.h"@class KCStatus;@interface KCStatusService : NSObjectsingleton_interface(KCStatusService)/** * 添加微博信息 * * @param status 微博对象 */-(void)addStatus:(KCStatus *)status;/** * 删除微博 * * @param status 微博对象 */-(void)removeStatus:(KCStatus *)status;/** * 修改微博内容 * * @param status 微博对象 */-(void)modifyStatus:(KCStatus *)status;/** * 根据编号取得微博 * * @param Id 微博编号 * * @return 微博对象 */-(KCStatus *)getStatusById:(int)Id;/** * 取得所有微博对象 * * @return 所有微博对象 */-(NSArray *)getAllStatus;@end
KCStatusService.m
//// KCStatusService.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCStatusService.h"#import "KCDbManager.h"#import "KCStatus.h"#import "KCUserService.h"#import "KCSingleton.h"@interface KCStatusService(){ }@end@implementation KCStatusServicesingleton_implementation(KCStatusService)-(void)addStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"INSERT INTO Status (source,createdAt,\"text\" ,user) VALUES('%@','%@','%@','%@')",status.source,status.createdAt,status.text,status.user.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)removeStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"DELETE FROM Status WHERE Id='%@'",status.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(void)modifyStatus:(KCStatus *)status{ NSString *sql=[NSString stringWithFormat:@"UPDATE Status SET source='%@',createdAt='%@',\"text\"='%@' ,user='%@' WHERE Id='%@'",status.source,status.createdAt,status.text,status.user, status.Id]; [[KCDbManager sharedKCDbManager] executeNonQuery:sql];}-(KCStatus *)getStatusById:(int)Id{ KCStatus *status=[[KCStatus alloc]init]; NSString *sql=[NSString stringWithFormat:@"SELECT Id, source,createdAt,\"text\" ,user FROM Status WHERE Id='%i'", Id]; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; if (rows&&rows.count>0) { [status setValuesForKeysWithDictionary:rows[0]]; status.user=[[KCUserService sharedKCUserService] getUserById:[(NSNumber *)rows[0][@"user"] intValue]] ; } return status;}-(NSArray *)getAllStatus{ NSMutableArray *array=[NSMutableArray array]; NSString *sql=@"SELECT Id, source,createdAt,\"text\" ,user FROM Status ORDER BY Id"; NSArray *rows= [[KCDbManager sharedKCDbManager] executeQuery:sql]; for (NSDictionary *dic in rows) { KCStatus *status=[self getStatusById:[(NSNumber *)dic[@"Id"] intValue]]; [array addObject:status]; } return array;}@end 最后，在视图控制器中调用相应的服务层进行各类数据操作，在下面的代码中分别演示了增、删、改、查四类操作。
KCMainViewController.m
//// KCMainTableViewController.m// DataAccess//// Created by Kenshin Cui on 14-3-29.// Copyright (c) 2014年 Kenshin Cui. All rights reserved.//#import "KCMainTableViewController.h"#import "KCDbManager.h"#import "KCDatabaseCreator.h"#import "KCUser.h"#import "KCStatus.h"#import "KCUserService.h"#import "KCStatusService.h"#import "KCStatusTableViewCell.h"@interface KCMainTableViewController (){ NSArray *_status; NSMutableArray *_statusCells;}@end@implementation KCMainTableViewController- (void)viewDidLoad { [super viewDidLoad]; [KCDatabaseCreator initDatabase]; // [self addUsers];// [self removeUser];// [self modifyUserInfo]; // [self addStatus]; [self loadStatusData]; }-(void)addUsers{ KCUser *user1=[KCUser userWithName:@"Binger" screenName:@"冰儿" profileImageUrl:@"binger.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user1]; KCUser *user2=[KCUser userWithName:@"Xiaona" screenName:@"小娜" profileImageUrl:@"xiaona.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user2]; KCUser *user3=[KCUser userWithName:@"Lily" screenName:@"丽丽" profileImageUrl:@"lily.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user3]; KCUser *user4=[KCUser userWithName:@"Qianmo" screenName:@"阡陌" profileImageUrl:@"qianmo.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user4]; KCUser *user5=[KCUser userWithName:@"Yanyue" screenName:@"炎月" profileImageUrl:@"yanyue.jpg" mbtype:@"mbtype.png" city:@"北京"]; [[KCUserService sharedKCUserService] addUser:user5];}-(void)addStatus{ KCStatus *status1=[KCStatus statusWithCreateAt:@"9:00" source:@"iPhone 6" text:@"一只雪猴在日本边泡温泉边玩iPhone的照片，获得了\"2014年野生动物摄影师\"大赛特等奖。一起来为猴子配个词" userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status1]; KCStatus *status2=[KCStatus statusWithCreateAt:@"9:00" source:@"iPhone 6" text:@"一只雪猴在日本边泡温泉边玩iPhone的照片，获得了\"2014年野生动物摄影师\"大赛特等奖。一起来为猴子配个词" userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status2]; KCStatus *status3=[KCStatus statusWithCreateAt:@"9:30" source:@"iPhone 6" text:@"【我们送iPhone6了 要求很简单】真心回馈粉丝，小编觉得现在最好的奖品就是iPhone6了。今起到12月31日，关注我们，转发微博，就有机会获iPhone6(奖品可能需要等待)！每月抽一台[鼓掌]。不费事，还是试试吧，万一中了呢" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status3]; KCStatus *status4=[KCStatus statusWithCreateAt:@"9:45" source:@"iPhone 6" text:@"重大新闻：蒂姆库克宣布出柜后，ISIS战士怒扔iPhone，沙特神职人员呼吁人们换回iPhone 4。[via Pan-Arabia Enquirer]" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status4]; KCStatus *status5=[KCStatus statusWithCreateAt:@"10:05" source:@"iPhone 6" text:@"小伙伴们，有谁知道怎么往Iphone4S里倒东西？倒入的东西又该在哪里找？用了Iphone这么长时间，还真的不知道怎么弄！有谁知道啊？谢谢！" userId:4]; [[KCStatusService sharedKCStatusService] addStatus:status5]; KCStatus *status6=[KCStatus statusWithCreateAt:@"10:07" source:@"iPhone 6" text:@"在音悦台iPhone客户端里发现一个悦单《Infinite 金明洙》，推荐给大家! " userId:1]; [[KCStatusService sharedKCStatusService] addStatus:status6]; KCStatus *status7=[KCStatus statusWithCreateAt:@"11:20" source:@"iPhone 6" text:@"如果sony吧mp3播放器产品发展下去，不贪图手头节目源的现实利益，就木有苹果的ipod，也就木有iphone。柯达类似的现实利益，不自我革命的案例也是一种巨头的宿命。" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status7]; KCStatus *status8=[KCStatus statusWithCreateAt:@"13:00" source:@"iPhone 6" text:@"【iPhone 7 Plus】新买的iPhone 7 Plus ，如何？够酷炫么？" userId:2]; [[KCStatusService sharedKCStatusService] addStatus:status8]; KCStatus *status9=[KCStatus statusWithCreateAt:@"13:24" source:@"iPhone 6" text:@"自拍神器#卡西欧TR500#，tr350S～价格美丽，行货，全国联保～iPhone6 iPhone6Plus卡西欧TR150 TR200 TR350 TR350S全面到货 招收各种代理！[给力]微信：39017366" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status9]; KCStatus *status10=[KCStatus statusWithCreateAt:@"13:26" source:@"iPhone 6" text:@"猜到猴哥玩手机时所思所想者，再奖iPhone一部。（奖品由“2014年野生动物摄影师”评委会颁发）" userId:3]; [[KCStatusService sharedKCStatusService] addStatus:status10];}-(void)removeUser{ //注意在SQLite中区分大小写 [[KCUserService sharedKCUserService] removeUserByName:@"Yanyue"];}-(void)modifyUserInfo{ KCUser *user1= [[KCUserService sharedKCUserService]getUserByName:@"Xiaona"]; user1.city=@"上海"; [[KCUserService sharedKCUserService] modifyUser:user1]; KCUser *user2= [[KCUserService sharedKCUserService]getUserByName:@"Lily"]; user2.city=@"深圳"; [[KCUserService sharedKCUserService] modifyUser:user2];}#pragma mark 加载数据-(void)loadStatusData{ _statusCells=[[NSMutableArray alloc]init]; _status=[[KCStatusService sharedKCStatusService]getAllStatus]; [_status enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) { KCStatusTableViewCell *cell=[[KCStatusTableViewCell alloc]init]; cell.status=(KCStatus *)obj; [_statusCells addObject:cell]; }]; NSLog(@"%@",[_status lastObject]);}#pragma mark - Table view data source- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1;}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return _status.count;}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *identtityKey=@"myTableViewCellIdentityKey1"; KCStatusTableViewCell *cell=[self.tableView dequeueReusableCellWithIdentifier:identtityKey]; if(cell==nil){ cell=[[KCStatusTableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:identtityKey]; } cell.status=_status[indexPath.row]; return cell;}-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{ return ((KCStatusTableViewCell *)_statusCells[indexPath.row]).height;}-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section{ return 20.0f;}@end 项目目录结构：