/**
* New query builder.
* @param string|null $stack
* @return Oppa\Query\Builder
*/
public final function queryBuilder(string $stack = null) : QueryBuilder
{
$queryBuilder = new QueryBuilder();
$queryBuilder->setLink($this->db->getLink());
// use self name
if ($stack == '') {
$stack = $this->stack;
}
$queryBuilder->setTable($stack);
return $queryBuilder;
}
