尝试在codeigniter活动记录中追加（添加）小时列

I am trying to store hours for a worker in a database. So that when they checkout the hours in a row are added to for the day my active record query wont work though?

Here is what i am doing in my model class.

function update_daily_row($email,$date,$hours)//update existing row.
{

      $this->db->where('email', $email);
      $this->db->where('date', $date);
      $this->db->set('hours', 'hours + $hours', FALSE);
      $this->db->update('dailyinfo'); 
 }

The query comes out like this so it doesnt read the hours variable

UPDATE `tablename` SET `hours` = hours + $hours WHERE `email` = 'email@yahoo.com' AND     `date` = '2013-10-08'

How to do it properly?

You should read the hours out first and then add it $hours

function update_daily_row($email,$date,$hours)//update existing row.
{

      $this->db->where('email', $email);
      $this->db->where('date', $date);

      $origin_hours = $this->db->get('dailyinfo')->first_row()->hours;
      $update_hours = $original_hour + $hours;

      $this->db->set('hours', $update_hours, FALSE);
      $this->db->update('dailyinfo'); 
 }

Try this code:

function update_daily_row($email,$date,$hours)//update existing row.
{
      $this->db->where('email', $email);
      $this->db->where('date', $date);
      $this->db->set('hours', 'hours + '. $hours, FALSE);
      $this->db->update('dailyinfo'); 
}