Konfigurasikan sambungan pangkalan data PHP untuk sistem pengurusan pangkalan data yang berbeza

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

$host = "localhost";
$port = 5432;
$dbname = "myDB";
$username = "postgres";
$password = "mypassword";

// 创建连接
$conn = pg_connect("host=$host port=$port dbname=$dbname user=$username password=$password");

// 检查连接
if (!$conn) {
    die("连接失败: " . pg_last_error($conn));
}

$serverName = "localhost";
$connectionInfo = array("Database"=>"myDB", "UID"=>"sa", "PWD"=>"mypassword");

// 创建连接
$conn = sqlsrv_connect($serverName, $connectionInfo);

// 检查连接
if ($conn === false) {
    die("连接失败: " . sqlsrv_errors());
}

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 执行查询
$sql = "SELECT * FROM users";
$result = $conn->query($sql);

// 遍历结果
if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"] . " - Name: " . $row["name"] . "
";
    }
} else {
    echo "没有数据";
}

// 关闭连接
$conn->close();