PHP 데이터베이스 연결에 대한 궁극적인 가이드: 알아야 할 모든 것을 다룹니다.

$mysqli = mysqli_connect("localhost", "root", "password", "database_name");

if ($mysqli->connect_errno) {
  echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}

$mysqli = mysqli_pconnect("localhost", "root", "password", "database_name");

$stmt = $mysqli->prepare("SELECT * FROM users WHERE username = ?");
$stmt->bind_param("s", $username);
$stmt->execute();

$mysqli->begin_transaction();
$mysqli->query("INSERT INTO orders (product_id, quantity) VALUES (1, 5)");
$mysqli->commit();

$mysqli = mysqli_connect("localhost", "root", "password", "database_name");

if ($mysqli->connect_errno) {
  echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}

$sql = "SELECT * FROM users";
$result = $mysqli->query($sql);

if ($result->num_rows > 0) {
  while ($row = $result->fetch_assoc()) {
    echo "ID: " . $row["id"] . "
";
    echo "Username: " . $row["username"] . "
";
    echo "Email: " . $row["email"] . "

";
  }
} else {
  echo "No users found.";
}

$mysqli->close();