Codeigniter调度系统

Question

I am creating a scheduling system for hr department to use and I am using codeigniter framework to make my code readable and fast to execute. The problem that I am facing now is that I don't know how to make the schedule last from the date it was set till the next change schedule meaning I only have date started from schedule and not having date end because the employees might be fix to that schedule for long time. Here is my query:

function retrieve_Sched($id)
{
    $query = "SELECT * FROM schedule WHERE EmpID = ?";

    $query = $this->db->query($query,array($id));

    if($query->num_rows() == 0)
    {
        return false;
    }
    else
    {
        return $query->result_array();
    }
}

and I want to compare it to their actual attendance to get if they have accumulated overtime.

Answer 1

I solved my problem by adding additional field name isDefault and the query must always check if that is the default schedule of the employee and if the employee change his/her schedule from the previous, the schedule that have the isDefault will be updated to null or value 0 and making the new schedule with the value of 1. Thanks for the people who comments to this post and to the one who gave me negative....