define("NEWDB" , "site.ru");
$dbcnx = mysqli_connect($DBhost,$DBuser,$DBpass);
$createDB = "CREATE DATABASE ".NEWDB;
if (mysqli_query($dbcnx, $createDB)) {
echo "Database ".NEWDB." created successfully<br>";
} else {
echo "Error creating database: " . mysqli_error($dbcnx).'<br>';
}