Increment data in codeigniter

Question

Here's my code

    $receipt = $_POST['receipt'];
    $invid = $_POST['invid'];
    // $receipt = intval($receipt);
    // $invid = intval($invid);

    $newreceipt = 0;
    $GTextension = 'GT-';
    $UTextension = 'UT-';
    $rec_type = array(1472,1416,9752,1417,1500);
    $last_receipt = $this->ion_auth->getLastReceipt($receipt);
    if($last_receipt->num_rows() > 0){
        if($receipt == 1){
            $newreceipt = $last_receipt->row()->inv_cno+1;
        }
        elseif($receipt == 2){
            $newreceipt = $last_receipt->row()->inv_cno+1;
        }
        elseif($receipt == 3){
            $newreceipt = $last_receipt->row()->inv_cno+1;
        }
        elseif($receipt == 4){
            $newreceipt = $UTextension.(++$last_receipt->row()->inv_cno);
        }
        else if($receipt == 5){
            $newreceipt = $GTextension.(++$last_receipt->row()->inv_cno);
        }
    }

    $this->ion_auth->update_receipt($invid,$receipt,$newreceipt);

    $return = array('dr_no' => $newreceipt);

    echo json_encode($return);

Now the output of this code is like this if i choose ==4 then it it is like this

UT-1418 it's correct.

then if i choose again ==4 the problem exist because it is now like this UT-UT-1419. It's incrementing also the extension. All i want to increment is the data which is -1419

Can someone help me please. Thank you.

Lorenzo S · Answer 1 · 2018-11-08T09:44:36.983

If $receipt === 4 you are executing this:

$newreceipt = $UTextension.(++$last_receipt->row()->inv_cno);

and then you are saving the value in the DB with $this->ion_auth->update_receipt($invid,$receipt,$newreceipt);.

So, now, the database contains "UT-something".

Now, if you execute this simple code in PHP, you will probably get the point:

$test = "UT-10";
++$test;
echo "$test\n";

It will output UT-11. You can take a look at some official documentation to understand why this works like this.

So, what happens is that the next time that $receipt === 4, you perform the same code: $newreceipt = $UTextension.(++$last_receipt->row()->inv_cno);

that is equivalent to "UT-" . "UT-*something*".

And so the unwanted result.

Now, the solution is up to your needs: If inv_cno has to be an integer, you just save the integer and you calculate back the "prefix-" . inv_cno in the code.

Otherwise, you should just check if the $last_receipt->row()->inv_cno already has a prefix in it, in order to understand if you have to add/change it or not.

EDIT --- after user comments.

Now that we now it is a varchar, assuming that the prefix is always a 3 characters string ("UT-", "GT-" and so on), you can create something like this. According to your example, I assume that inv_cno can already have or not have a prefix. And I assume that the admissible prefixes are "UT-" and "GT-".

I will write you an example here to make you understand my point, then you will have to integrate it in your code :)

<?php

function get_new_receipt($inv_cno, $extension) {
  $prefix_len = 3;
  $admissible_prefixes = array("UT-", "GT-");
  $inv_cno++;
  if (strlen($inv_cno) <= $prefix_len) {
    return $extension . $inv_cno;
  }
  $current_prefix = substr($inv_cno, 0, $prefix_len);
  if ($current_prefix === $extension) {
    return $inv_cno;
  }

  return $extension . substr($inv_cno, $prefix_len);
}


$test = "UT-10";

$test = get_new_receipt($test, "UT-");
echo "$test\n";

$test = get_new_receipt($test, "UT-");
echo "$test\n";

$test = get_new_receipt($test, "GT-");
echo "$test\n";

P.S.: Anyway, as a side note, it's not so safe to perform this kind of math over strings. But that's another story.

i'll be honest. It's kind of hard to implement . I'm sorry but I will try. — , Nov 08 '18 at 09:59
and could you explain the code more sir so i can understand it clearly — , Nov 08 '18 at 10:05

score 0 · Accepted Answer · answered Nov 08 '18 at 10:25

Done it like this

$prefix = 'UT-'; 
elseif($receipt == 4){
       if (substr($UTextension, 0, strlen($prefix)) == $prefix) {
                $UTextension = substr($UTextension, strlen($prefix));
                $newreceipt = $UTextension. (++$last_receipt->row()->inv_cno);
       }
 }

Thanks Lorenzo S

Increment data in codeigniter

2 Answers2