iOS sqlite3 的基本使用(增 删 改 查)

//

//  ViewController.m

//  test_sqlite

//

//  Created by 郑玉洋 on 2017/4/13.

//  Copyright © 2017年郑玉洋. All rights reserved.

//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)addSql:(id)sender{

    //为了测试这里利用随机数与for循环进行多次插入不同数据

    

    for (NSInteger i =0; i < 10; i++) {

        NSString * sql = [NSStringstringWithFormat:@"insert into t_text ('%@') values ('%@');",@"name", [NSStringstringWithFormat:@"测试--%zd",arc4random_uniform(99) ]];

        

        char * errmsg;

        sqlite3_exec(db, sql.UTF8String,NULL, NULL, &errmsg);

        if (errmsg) {

            NSLog(@"插入失败--%s",errmsg);

        }else{

            NSLog(@"插入成功");

        }

    }

}

- (void)delSql:(id)sender{

    //这里删除随机id大于3 小于6的

    //操作代码(sql)

    NSString * sql =@"delete from t_text where id > 3 and id < 6;";

    char * errmsg;

    sqlite3_exec(db, sql.UTF8String,NULL, NULL, &errmsg);

    if (errmsg) {

        NSLog(@"删除失败--%s",errmsg);

    }else{

        NSLog(@"删除成功");

    }

}

- (void)updateSql:(id)sender{

    //这里吧id为9的 name更改为 hello-world

    //操作代码(sql)

    NSString * sql =@"update t_text set name = 'hello-world' where id = 9;";

    char * errmsg;

    sqlite3_exec(db, sql.UTF8String,NULL, NULL, &errmsg);

    if (errmsg) {

        NSLog(@"修改失败--%s",errmsg);

    }else{

        NSLog(@"修改成功");

    }

}

- (void)selectSql:(id)sender{

    //查询所有信息

    //操作代码(sql)

    

    NSString * sql =@"select * from t_text;";

    

    //查询的句柄,游标

    sqlite3_stmt * stmt;

    

    if (sqlite3_prepare(db, sql.UTF8String, -1, &stmt, NULL) ==SQLITE_OK) {

        

        //查询数据

        while (sqlite3_step(stmt) ==SQLITE_ROW) {

            

            //获取表数据的内容

            //sqlite3_column_text('句柄'，字段索引值)

            

            NSString * name = [NSStringstringWithCString:(constchar *)sqlite3_column_text(stmt,1) encoding:NSUTF8StringEncoding];

            

            NSLog(@"name = %@",name);

            

        }

    }

}

- (void)viewDidLoad {

    [superviewDidLoad];

    

    UIButton *addBtn = [[UIButtonalloc] initWithFrame:CGRectMake(100,100, 30,15)];

    addBtn.backgroundColor = [UIColorblueColor];

    [addBtn addTarget:selfaction:@selector(addSql:)forControlEvents:UIControlEventTouchUpInside];

    [self.viewaddSubview:addBtn];

    

    UIButton *delBtn = [[UIButtonalloc] initWithFrame:CGRectMake(100,200, 30,15)];

    delBtn.backgroundColor = [UIColorblueColor];

    [delBtn addTarget:selfaction:@selector(delSql:)forControlEvents:UIControlEventTouchUpInside];

    [self.viewaddSubview:delBtn];

    

    UIButton *updateBtn = [[UIButtonalloc] initWithFrame:CGRectMake(100,300, 30,15)];

    updateBtn.backgroundColor = [UIColorblueColor];

    [updateBtn addTarget:selfaction:@selector(updateSql:)forControlEvents:UIControlEventTouchUpInside];

    [self.viewaddSubview:updateBtn];

    

    UIButton *selectBtn = [[UIButtonalloc] initWithFrame:CGRectMake(100,600, 30,15)];

    selectBtn.backgroundColor = [UIColorblueColor];

    [selectBtn addTarget:selfaction:@selector(selectSql:)forControlEvents:UIControlEventTouchUpInside];

    [self.viewaddSubview:selectBtn];

    

    //设置数据库的路径

    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES)firstObject];

    NSString *fileName = [pathstringByAppendingPathComponent:@"text.sqlite"];

    NSLog(@"fileName = %@",fileName);

    

    //打开数据库如果没有打开的数据库就建立一个

    //第一个参数是数据库的路径注意要转换为c的字符串

    if (sqlite3_open(fileName.UTF8String, &db) == SQLITE_OK) {

        NSLog(@"打开数据库成功");

        //打开数据库成功后建立数据库内的表

        //操作命令的字符串

        //注意字符串的结束处有 ;号

        NSString * sql =@"create table if not exists t_text (id integer primary key autoincrement,name text);";

        char * errmsg;

        sqlite3_exec(db, sql.UTF8String,NULL, NULL, &errmsg);

        if (errmsg) {

            NSLog(@"建表失败 -- %s",errmsg);

        }else{

            NSLog(@"建表成功");

        }

    }else{

        NSLog(@"打开数据库失败");

    }

}

@end