mysql如何连接PHP程序_PHP连接mysql数据库的详细步骤

CREATE DATABASE mywebsite;
CREATE USER 'myuser'@'localhost' IDENTIFIED BY 'mypassword';
GRANT ALL PRIVILEGES ON mywebsite.* TO 'myuser'@'localhost';
FLUSH PRIVILEGES;

$host = 'localhost';
$dbname = 'mywebsite';
$username = 'myuser';
$password = 'mypassword';
<p>$conn = new mysqli($host, $username, $password, $dbname);</p><p>if ($conn->connect_error) {
die("连接失败: " . $conn->connect_error);
}
echo "数据库连接成功";</p>

$conn = mysqli_connect('localhost', 'myuser', 'mypassword', 'mywebsite');
<p>if (!$conn) {
die("连接失败: " . mysqli_connect_error());
}
echo "数据库连接成功";</p>

$host = 'localhost';
$dbname = 'mywebsite';
$username = 'myuser';
$password = 'mypassword';
$charset = 'utf8mb4';
<p>try {
$dsn = "mysql:host=$host;dbname=$dbname;charset=$charset";
$pdo = new PDO($dsn, $username, $password);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "PDO连接成功";
} catch (PDOException $e) {
die("连接失败: " . $e->getMessage());
}</p>

$sql = "SELECT id, name FROM users LIMIT 5";
$result = $conn->query($sql);
<p>if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo "ID: " . $row["id"]. " - 名称: " . $row["name"]. "<br>";
}
} else {
echo "0 条结果";
}</p>

$conn->close();  // MySQLi
// 或
$pdo = null;     // PDO