You created DDL statement object and Adapter, but you haven't executed it. You will need 1 more object for execution and that's SQL instance. In your case it could look like this:
use Zend\Db\Sql\Sql;
// your code
$sql = new Sql($DB);
$DB->query(
$sql->getSqlStringForSqlObject($table),
$DB::QUERY_MODE_EXECUTE
);
More at Zend Framework's docs