使用 PHP 连接到 MySQL 的问题

Question

我正在尝试使用 PHP 连接到 MySQL，但我不断收到以下错误：“mysqli::__construct(): (HY000/2002): /Users/markjonathas/Documents/bar/database_connection.php 上没有这样的文件或目录第 9 行”我已经下载了 MAMP，我使用的是 PHP 7.3.1 和 MySQL 8.0.16 版。

我曾尝试下载 Sequel Pro，但是当我尝试连接到数据库时，出现以下错误：“MySQL 说：无法加载身份验证插件 'caching_sha2_password'：dlopen(/usr/local/lib/plugin/caching_sha2_password.so , 2): 找不到图像"

//code for database_connection.php:

<?php

    $servername = "127.0.0.1:3306";

    $username = "root";

    $password = "-------";

    $database = "barDB";

    function db_connect() {

        $connection = new mysqli($servername, $username, $password, 

$database);

        return $connection;

    }

    function db_disconenct() {

        if(isset($connection)) {

            $connection->close();

        }

    }

?>

//code for connecting to database_connection.php:

<?php

        require_once("database_connection.php");

        $db = db_connect();

?>

Answer 1

创建一个文件并将其命名为 init.php 或您想要的任何名称。<?php&nbsp; &nbsp; $db_name = "barDB";&nbsp; &nbsp; $mysql_user = "root";&nbsp; &nbsp; $mysql_pass = "-------";&nbsp; &nbsp; $server_name = "127.0.0.1:3306";&nbsp; &nbsp; $con = mysqli_connect($server_name, $mysql_user, $mysql_pass, $db_name);&nbsp; &nbsp; if(!$con){&nbsp; &nbsp; &nbsp; &nbsp; echo "Server Error";&nbsp; &nbsp; }else{&nbsp; &nbsp; }?>

Answer 2

要访问全局变量，您必须将它们声明为全局变量：function db_connect() {&nbsp; &nbsp; global $connection, $servername, $username, $password, $database; // <<<<<<<<&nbsp; &nbsp; $connection = new mysqli($servername, $username, $password, $database);&nbsp; &nbsp; return $connection;}function db_disconenct() {&nbsp; &nbsp; global $connection; // <<<<<&nbsp; &nbsp; if(isset($connection)) {&nbsp; &nbsp; &nbsp; &nbsp; $connection->close();&nbsp; &nbsp; }}有关详细信息，请阅读 PHP 文档。