/**
* Execute the given SQL query.
* This abstract function must be defined by subclasses as part of the actual implementation.
* It should return a subclass of SS_Query as the result.
*
* @param string $sql The SQL query to execute
* @param int $errorLevel The level of error reporting to enable for the query
* @return Query
*/
public function query($sql, $errorLevel = E_USER_ERROR)
{
return $this->database->query($sql, $errorLevel);
}