[eluser]Alhazred[/eluser]
To debug printing some values I also added an exit; in a not convenient place, now I've removed it, put somewhere else and I think I've found the problem.
My query is inside a while which is inside a transaction, this is the code with the debug lines
Code:
$this->db->trans_begin();
while($inserzione['active_banner'] > 0)
{
//row to update selection which ends with
$row = $result->row_array();
$set = array('banner' => $row['banner']+1); //$row['banner'] contains the old number of banners
$this->db->where('id',$row['id']);
$this->db->update($table,$set);
echo $this->db->last_query()."<br />"; //debug string
if ( $this->db->affected_rows() == 1)
{
$inserzione['active_banner']--;
}
else //update error
{
$this->db->trans_rollback();
echo 'Inside the else<br />'; //debug string
exit; //stop to see the printed strings
return FALSE;
}
}
if ($this->db->trans_status() !== FALSE)
{
$this->db->commit();
return TRUE;
}
else
{
$this->db->rollback();
return FALSE;
}
the problem appears when $inserzione['active_banner'] is > 1 and for the 1st and 2nd iteration is selected the same entry to update.
The output is
UPDATE `prodotti` SET `banner` = 3 WHERE `id` = '1-1344638814-2'
UPDATE `prodotti` SET `banner` = 3 WHERE `id` = '1-1344638814-2'
Inside the else
for both the iteration, the value to set is 3.
I think that happens as follow:
$inserzione['active_banners'] = 2
1st iteration
entry with 1-1344638814-2 id is selected
banner = 2
banner + 1 = 3
UPDATE `prodotti` SET `banner` = 3 WHERE `id` = '1-1344638814-2' is executed and succeeds
$inserzione['active_banners'] = 1
2nd iteration
entry with 1-1344638814-2 id is selected again
banner = 2
banner + 1 = 3
UPDATE `prodotti` SET `banner` = 3 WHERE `id` = '1-1344638814-2' is executed and result_rows is 0 because the banner value is already 3
The problem is that the 2nd iteration reads again the value actually stored into the db, not the updated one from the 1st iteration, so the "new" value is again 3 and not 4.
I think I have to change the logic.
