php后台框架的数据库连接方式

PHP后台框架通常使用PDO（PHP Data Objects）或者MySQLi（MySQL Improved）这两种方式来连接数据库。

$servername = "localhost";$username = "username";$password = "password";$dbname = "dbname";try {    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);    echo "Connected successfully";} catch(PDOException $e) {    echo "Connection failed: " . $e->getMessage();}

$servername = "localhost";$username = "username";$password = "password";$dbname = "dbname";$conn = new mysqli($servername, $username, $password, $dbname);if ($conn->connect_error) {    die("Connection failed: " . $conn->connect_error);}echo "Connected successfully";

这两种连接方式都可以用来连接MySQL数据库，但PDO更加灵活和方便，支持多种数据库类型，而MySQLi只支持MySQL数据库。在实际开发中，可以根据具体需求来选择适合自己项目的数据库连接方式。