PHP mysql 错误调用未定义的函数 mysql_connect()

Question

我一直在尝试找出问题所在

<?php
require_once("config.php");

class MYSQLDatabase{

    private $connection;
// open the connection as soon as object is created
function __construct(){

    $this->open_connection();
}

public function open_connection(){

    $this->connection = mysql_connect("DB_SERVER", "DB_USER", "DB_PASS");

    if(!$this->connection){
        die("Database failed " . mysql_error());
    }else{
     $db_select = mysql_select_db(DB_NAME, $this->connection);   
        if(!$db_select){
            die("Database connection failed " . mysql_error());
        }
    }
}

    public function close_connection(){
        if(isset($this->connection)){
            mysql_close($this->connection);
            unset($this->connection);
        }
    }

    public function query($sql){
        $result = mysql_query($sql, $this->connection);
        $this->confirm_query($result);
        return $result;
    }



    private function confirm_query($result){
        if(!result){
            die("Database query failed: " . mysql_error());
        }
    }
}
$database = new MYSQLDatabase();

?>

当我转到 index.php 文件并使用下面的代码测试该类时，出现以下错误:
该页面无法正常工作

localhost 当前无法处理此请求。HTTP 错误 500。

require_once("../includes/database.php");
if(isset($database)){
    echo "true";
}else{
    echo "false";
}

Answer 1

正如我刚刚在评论中提到的，mysql 扩展已从 PHP 7 中删除，正如 PHP 手册中所述 mysql is deleted from php 7这就是为什么你收到错误 undefined function mysql

使用mysqli，它是mysql的改进版本。如果您不知道如何使用，这里有一个示例。

<?php
 // no need fo mysqli_select_db 
$con = mysqli_connect("localhost","my_user","my_password","my_db");

// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }
?>

有关更多示例，请查看 W3schools