IOS学习笔记2015-04-090C-SQLite数据存储

////  ViewController.m//  SQLiteDemo////  Created by wangtouwang on 15/4/9.//  Copyright (c) 2015年 wangtouwang. All rights reserved.//#import "ViewController.h"#import "WPUser.h"#define DBNAME @ "MySQLite.sqlite"@interface ViewController (){    sqlite3 *db;}@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];        [self createSqlDBOrOpenDB];        [self createTable];    //    for (int index=0; index<30; index++) {//         [self insertIntoData];//    }    [self updateData:[self searchAllData]];        }#PRagma mark 更新数据 -(void)updateData:(NSMutableArray *)array{    NSString *sql = @"update user set name=?,age=? where id=?";    sqlite3_stmt *stmt;    for (int index=0; index<array.count; index++) {        WPUser *user =  (WPUser *)array[index];        user.name=@"张建华";        user.age=31;        if (sqlite3_prepare_v2(db, [sql UTF8String], -1, &stmt, NULL)==SQLITE_OK) {            sqlite3_bind_text(stmt, 1, [user.name UTF8String], -1, NULL);            sqlite3_bind_int(stmt, 2, user.age);            sqlite3_bind_int(stmt, 3, user.ID);            if (sqlite3_step(stmt)==SQLITE_DONE) {                NSLog(@"更新成功");            }        }    }}#pragma mark 读取数据 -(NSMutableArray *)searchAllData{    NSMutableArray *array = [NSMutableArray array];    NSString *sql = @"select id,name,age from user";    sqlite3_stmt *stmt;    if (sqlite3_prepare_v2(db, [sql UTF8String], -1, &stmt, NULL)==SQLITE_OK) {        while (sqlite3_step(stmt)==SQLITE_ROW) {            NSInteger ID =  sqlite3_column_int(stmt, 0);             char *name = (char*)sqlite3_column_text(stmt, 1);           NSString *uname = [[NSString alloc] initWithUTF8String:name];            NSInteger age = sqlite3_column_int(stmt, 2);            NSLog(@"ID=%lu NAME=%s AGE=%lu",ID,name,age);            WPUser *user = [WPUser initUserName:uname Age:age];            user.ID=ID;            [array addObject:user];        }    }     sqlite3_close(db);    return array;}#pragma mark 新增数据-(void)insertIntoData{    NSString *sql = @"insert into user(name,age) values(?,?)";    WPUser *user = [WPUser initUserName:@"JACK" Age:11];    sqlite3_stmt *stmt;    //插入数据前检测语法是否正确    if ((sqlite3_prepare_v2(db, [sql UTF8String], -1, &stmt, NULL))==SQLITE_OK ) {        //绑定参数 参数2:为序号（从1开始），参数3:为字符串值，参数4 为字符串长度。sqlite3_bind_text的第五个参数为一个函数指针        sqlite3_bind_text(stmt, 1, [user.name UTF8String], -1, NULL);        sqlite3_bind_int(stmt, 2,user.age);        //真正执行插入 sqlite3_step        if (sqlite3_step(stmt)==SQLITE_DONE) {            NSLog(@"INSERT INTO SUCCESS");        }else{            NSLog(@"INSERT INTO ERROR");        }    }}#pragma mark 创建表 -(void)createTable{    NSString *sql = @"create table if not exists user (id integer primary key autoincrement,name text,age integer);";    char *errormsg;    //执行创建语句 sqlite3_exex 是函数 参数一:数据库的句柄（db），参数二: 为sql语句，参数三 回调参数，是一个指向函数的指针，如果把callback前面的*改成^则就是一个block代码段，                                //参数四 可以写NULL，第五个参数为错误信息    //在这里创建需要先判断表是否已存在    int result = sqlite3_exec(db, [sql UTF8String], NULL, NULL, &errormsg);    if (result==SQLITE_OK) {        NSLog(@"创建成功");    }else{        NSLog(@"创建失败 愿因是:%s",errormsg);    }}#pragma mark 创建数据库实例或者打开数据实例-(void)createSqlDBOrOpenDB{    //获取 项目 Doucment文件目录地址    NSString  *doc =  [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];    NSLog(@"%@",doc);    //创建 SQLITE 文件或者获取该文件路径    NSString *DB_PATH = [doc stringByAppendingPathComponent:DBNAME];    NSLog(@"%@",DB_PATH);    //打开或者创建DB实例 这里用到C里面的语法和指针    int result = sqlite3_open([DB_PATH UTF8String], &db);//sqlite3_open方法名 参数 const filename DB文件路径,第二个参数就是数据库实例化对象 返回参数 int 类型    if(result!=SQLITE_OK){        sqlite3_close(db);//关闭实例化        NSLog(@"打开数据哭实例化对象失败");    }else{        NSLog(@"CREATE SUCCESS");    }}@end

////  WPUser.m//  SQLiteDemo////  Created by wangtouwang on 15/4/9.//  Copyright (c) 2015年 wangtouwang. All rights reserved.//#import "WPUser.h"@implementation WPUser-(instancetype)initUserName:(NSString *)name Age:(NSInteger)age{    if (self= [super init]) {        self.name = name;        self.age = age;    }    return self;}+(instancetype)initUserName:(NSString *)name Age:(NSInteger)age{    return [[WPUser alloc] initUserName:name Age:age];}@end