phpMyAdmin: Ferramenta Essencial para Administração de MySQL

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
 die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT id, firstname, lastname FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
 while($row = $result->fetch_assoc()) {
   echo "id: " . $row["id"]. " - Nome: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
 }
} else {
 echo "0 resultados";
}
$conn->close();
?>

-- Exemplo SQL para resolver erro errno: 150
ALTER TABLE `tabela` ADD INDEX `idx_coluna` (`coluna`);
-- Garantir referencial integridade
ALTER TABLE `tabela_dependente` ADD CONSTRAINT `fk_tabela`
FOREIGN KEY (`id_dependente`) REFERENCES `tabela` (`id`);