<?php

    header("Content-type: text/html;charset=utf-8");
    //mysqli操作mysql数据库(面向对象方式)

    //1、创建MySQLi对象

    $mysqli =new MySQLi("localhost","root","root","test");
    if($mysqli->connect_error){
        die("连接失败".$mysqli->connect_error);
    }

    //2、操作数据库（发送sql）
    $sql="select *from user1";

    //3、处理结果
    $res =$mysqli->query($sql);
    //var_dump($res);
    //fetch_assoc \fetch_array \fetch_object
    while($row=$res->fetch_row()){

        var_dump($row);

/*        foreach($row as $val){
            echo '--'.$val;
        }
        echo '<br/>';*/
    }
    //4、关闭资源
    $res->free();
    $mysqli->close();
?>

<?php

    header("Content-type: text/html;charset=utf-8");
    
    $mysqli=mysqli_connect("localhost","root","root","test");
    if(!$mysqli){
        die("连接失败".mysqli_connect_error());
    }

    $sql="select *from user1";

    $res=mysqli_query($mysqli,$sql);
    //var_dump($res);

    while($row=mysqli_fetch_row($res)){
        
        foreach ($row as $val){
            
            echo '-'.$val;
        }
        echo '<br/>';
    }

    //释放内存
    mysqli_free_result($res);
    mysqli_close($mysqli);
?>

<?php
    
    //使用mysqli 扩展库对mysql的crud 操作
    header("Content-type: text/html;charset=utf-8");
    $mysqli = new MySQLi("localhost","root","root","test");

    if($mysqli->connect_error){
        die("连接失败".$mysql->connect_error);
    }

    //增加一条记录
    //$sql="insert into user1 (name,password,email,age) values ('lucy',md5('lucy'),'lucy@163.com',17)";
    //删除一条记录
    //$sql="delete from user1 where id =80";
    //更新一条记录
    $sql="update user1 set age=20 where id=7";

    $res=$mysqli->query($sql);
    if(!$res){
        echo "操作失败".$mysqli->error;
    }else{
        if($mysqli->affected_rows>0){
            echo "成功";
        }else{
            echo "没有行受影响";    
        }
    }

    //关闭资源
    $mysqli->close();
?>

<?php

    //mysqli 增强-批量执行sql 语句

    //批量执行dql
    //使用mysqli的mysqli::multi_query() 一次性添加3个用户
    
    $mysqli =new MySQLi("localhost","root","root","test");
    if($mysqli->connect_error){
        die ("连接失败".$mysqli->connect_error);
    }
    
    //注意分号
    $sqls="insert into user1 (name,password,email,age) values('AAA',md5('AAA'),'AAA@hu.com',25);";
    $sqls.="insert into user1 (name,password,email,age) values('BBB',md5('BBB'),'BBB@hu.com',25);";
    $sqls.="insert into user1 (name,password,email,age) values('CCC',md5('CCC'),'CCC@hu.com',25);";
    
    //批量执行dml 可以混合使用delete insert update 最好不要使用select
    //$sqls.="update user1 set age=15 where id=1;";
    //$sqls.="delete from user1 where id=10";

    $res=$mysqli->multi_query($sqls);
    
    if(!$res){
        echo "操作失败".$mysqli->error;
    }else{
        echo "OK";
    }

?>

1 <?php
2 $subject = array('1', 'a', '2', 'b', '3', 'A', 'B', '4'); 
3 $pattern = array('/\d/', '/[a-z]/', '/[1a]/'); 
4 $replace = array('A:$0', 'B:$0', 'C:$0'); 
5 
6 echo "preg_replace returns\n<pre/>";
7 print_r(preg_replace($pattern, $replace, $subject)); 
8 ?>