No database selected

Bonjour,
lors de test de ce code j'ai un code d'erreur comme suit :
'SQLSTATE[3D000]: Invalid catalog name: 1046 No database selected'
et voila le code :
<?php
try {
$pdo = new PDO("mysql:host = localhost ; dbname = facturation" , "root" , "");
$pdo -> setAttribute(PDO::ATTR_ERRMODE , PDO::ERRMODE_EXCEPTION);
echo "connected";
echo "</br>";
$pdo -> getAttribute(constant("PDO::ATTR_CONNECTION_STATUS"));

} catch (PDOException $e) {
die("error : could not connected".$e -> getMessage());
}

?>
<?php
try {
$SQL = "SELECT * FROM clients";
$result = $pdo -> query($SQL);
if($result -> rowCount() > 0){
echo "<table>";
echo "<tr>";
echo "<th>idClient</th>";
echo "<th>nom</th>";
echo "<th>prenom</th>";
echo "<th>ville</th>";
echo "<th>tel</th>";
echo "</tr>";
while($row = $result -> fetch()) {
echo "<tr>";
echo "<td>" .$row['idClient']."</td>";
echo "<td>" .$row['nom'] ."</td>";
echo "<td>" .$row['prenom']."</td>";
echo "<td>" .$row['ville']."</td>";
echo "<td>" .$row['tel']."</td>";
echo "</tr>";
}
echo "</table>";
}else {
echo "no records matching";
}

} catch (PDOException $e) {
die("Error : ".$e ->getMessage());
}
?>