switch($typeDb)
{
    case 'mysql':
        mysql_query($query);
        break;
    case 'sqlite':
         sqlite_query($query);
         break;
    case 'mssql':
         mssql_query($query);
         break;
    case 'oci':
         $stid = oci_parse($conn, $query);
         oci_execute($stid);
    //etc...
}

SELECT *
FROM foo
WHERE id=? AND bar<?
LIMIT ?;

place holder #1 = 1
place holder #2 = 100
place holder #3 = 3

SELECT *
FROM foo
WHERE id=1 AND bar<100
LIMIT 3;

$strConnection = 'mysql:host=localhost;dbname=ma_base';
$arrExtraParam= array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8");
$pdo = new PDO($connStr, 'Utilisateur', 'Mot de passe', $arrExtraParam); //Instancie la connexion
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$query = 'INSERT INTO foo (nom, prix) VALUES (?, ?);';
$prep = $pdo->prepare($query);

$prep->bindValue(1, 'item 1', PDO::PARAM_STR);
$prep->bindValue(2, 12.99, PDO::PARAM_FLOAT);
$prep->execute();

$prep->bindValue(1, 'item 2', PDO::PARAM_STR);
$prep->bindValue(2, 7.99, PDO::PARAM_FLOAT);
$prep->execute();

$prep->bindValue(1, 'item 3', PDO::PARAM_STR);
$prep->bindValue(2, 17.94, PDO::PARAM_FLOAT);
$prep->execute();

$prep = NULL;

$query = 'SELECT * FROM foo WHERE id=:id AND cat=:categorie LIMIT :limit;';
$prep = $pdo->prepare($query);

$prep->bindValue(':limit', 10, PDO::PARAM_INT);
$prep->bindValue(':id', 120, PDO::PARAM_INT);
$prep->bindValue(':categorie', 'bar', PDO::PARAM_STR);
$prep->execute();

$arrAll = $prep->fetchAll();

$prep->closeCursor();
$prep = NULL;

$arr = array(12, 62, 61, 36, 92); //Le nombre d'éléments est variable.

//Créer une chaine de place holder
$arrPH = array();
foreach($arr as $elem)
    $arrPH[] = '?';
$strPH = implode(',', $arrPH); //Contient: ?,?,?,?,?

//Préparer la requête
$query = 'SELECT * FROM foo WHERE id IN(' . $strPH . ');';
$prep = $pdo->prepare($query);

//Associer les valeurs aux place holders
for($i=0;$i<count($arr);$i++)
    $prep->bindValue($i+1, $arr[$i], PDO::PARAM_INT);

$prep->execute();
$arrAll = $prep->fetchAll();
$prep->closeCursor();
$prep = NULL;

$query = 'SELECT * FROM foo;';
$pdo->prepare($query);
$prep = $pdo->execute();			

echo $prep->rowCount() . ' résultat(s)';

//Autre manipulations hors-contexte
$arrAll = $prep->fetchAll();
var_dump($arrAll);

$query = 'SELECT * FROM foo;';
$statement = $pdo->query();

echo $statement->rowCount() . ' résultat(s)';

//Autre manipulations hors-contexte
$arrAll = $statement->fetchAll();
var_dump($arrAll);

$query = 'SELECT * FROM foo LIMIT 1;';
$pdo->prepare($query);
$prep = $pdo->execute();
$arr = $prep->fetch();

if($arr !== false)
{
	echo 'Les données sont disponibles:';
	var_dump($arr);
}
else
{
	echo 'Aucun résultat disponible.';
}

$query = 'SELECT * FROM foo;';
$pdo->prepare($query);
$prep = $pdo->execute();
$arrAll = $prep->fetchAll();

if(!empty($arrAll))
{
	echo 'Les données sont disponibles:';
	foreach($arrAll as $arr)
	{
		echo '<br />Une ligne:';
		var_dump($arr);
	}
}
else
{
	echo 'Aucun résultat disponible.';
}

$query = 'DELETE FROM foo WHERE bar=?;';
$pdo->prepare($query);
$pdo->bindValue(1, 6, PDO::PARAM_INT);
$prep = $pdo->execute();

echo $prep->rowCount() . ' ligne(s) affectée(s).';

$query = 'DELETE FROM foo WHERE bar=6;';
$nbr = $pdo->exec($query);

echo $nbr() . ' ligne(s) affectée(s).';

$query = 'DELETE FROM foo LIMIT ?;';
$prep = $pdo->prepare($query);

$prep->bindValue(1, 10);  //Le problème est donc à cette ligne
$prep->execute();

DELETE FROM foo LIMIT '1';

$query = 'DELETE FROM foo LIMIT ?;';
$prep = $pdo->prepare($query);

$prep->bindValue(1, 10, PDO::PARAM_INT);
$prep->execute();