mysqli扩展库的 预处理技术 mysqli stmt

<?php

    //预编译演示
    //需求: 请使用预处理的方式，向数据库添加三个用户 
    //1.创建mysqli对象
    $mysqli=new MySQLi("localhost","root","hsp123","test");

    //2.创建预编译对象
    $sql="insert into user1 (name,password,email,age) values(?,?,?,?)";
    $mysqli_stmt=$mysqli->prepare($sql) or die($mysqli->error);//prepare（$sql）预处理函数
    //绑定参数
    $name="小倩";
    $password="xiaoqian";
    $email="aa@sohu.com";
    $age="200";
    //参数绑定->给?赋值,这里类型和顺序都要对应.
    //
    $mysqli_stmt->bind_param("sssi",$name,$password,$email,$age);
    //执行
    $b=$mysqli_stmt->execute();
    
    //继续添加
    $name="老妖";
    $password="laoyao";
    $email="laoyao@sohu.com";
    $age="210";

    $mysqli_stmt->bind_param("sssi",$name,$password,$email,$age);

    //执行
    $b=$mysqli_stmt->execute() ;
    
    //继续添加
    $name="菜层";
    $password="aaa";
    $email="aa@sohu.com";
    $age="30";
    $mysqli_stmt->bind_param("sssi",$name,$password,$email,$age);

    //执行
    $b=$mysqli_stmt->execute();

    if(!$b){
        die("操作失败".$mysqli_stmt->error);
    }else{
        echo "操作ok";
    }
    //释放
    $mysqli->close();

?>
    

<?php
function showTable($table_name){
        $mysqli=new MySQLi("localhost","root","hsp123","test");
        if(mysqli_connect_error()){
            die(mysqli_connect_error());
        }
        //$sql="select * from $table_name";
        $sql="desc user1";
        $res=$mysqli->query($sql);
        //如何获取返回总行数和列数
        echo "共有 行".$res->num_rows." -列=".$res->field_count;
        echo "<table border=‘1‘><tr>";
        //如何取出表头,从$res取出
        while($field=$res->fetch_field()){
            echo "<th>{$field->name}</th>";
        }
        echo "</tr>";
        //循环取出数据
        while($row=$res->fetch_row()){
            echo "<tr>";
            foreach($row as $val){
                echo "<td>$val</td>";
            }
            echo "</tr>";
        }
        echo "</table>";
        //关闭资源
        $res->free();
        $mysqli->close();
    }

    showTable("user1");
?>