Unwanted duplicate inserts

[agravayne]

Hello All,

 

I have a problem that I am tearing out my hair with. I cannot for the life of me find the source of this problem. I have the code below. It should insert a single row into credit_transaction table and then either insert a new row or update an existing one in indCredits table.

 

It correctly inserts the rows that it is supposed to but in both cases it adds a second row. This second row has lost the MemberID variable (which is a session variable) but the rest of the variables are ok?

 

I also output the sql query to the screen for testing purposes and enetraing the sql directly does not cause this odd behaviour -i.e. I only get the one row.

 

Has anyone got any idea what this could be?

 

<?php

session_start();

$inDate=date("Y-m-d");

$nlink=str_replace("'", "", $_POST['merchant_return_link']);


$sql = mysql_query("INSERT INTO `credit_transaction` (`id`, `from_id`, `to_id`, `date`, `user_id`, `no_of_credits`, `payer_last_name`, `payer_first_name`, `residence_country`, `item_name`, `payment_gross`, `mc_currency`, `business`, `payment_type`, `payer_status`, `verify_sign`, `test_ipn`, `payer_email`, `tax`, `mc_fee`, `payment_fee`, `shipping`, `mc_gross`, `txn_id`, `receiver_email`, `quantity`, `payer_id`, `receiver_id`, `item_number`, `payment_status`, `custom`, `charset`, `notify_version`, `merchant_return_link`) VALUES ('', '0', '$MemberID', '$indate', '$MemberID', '{$_POST['quantity']}', '{$_POST['last_name']}', '{$_POST['first_name']}', '{$_POST['residence_country']}', '{$_POST['item_name']}', '{$_POST['payment_gross']}', '{$_POST['mc_currency']}', '{$_POST['business']}', '{$_POST['payment_type']}', '{$_POST['payer_status']}', '{$_POST['verify_sign']}', '{$_POST['test_ipn']}', '{$_POST['payer_email']}', '{$_POST['tax']}', '{$_POST['mc_fee']}', '{$_POST['payment_fee']}', '{$_POST['shipping']}', '{$_POST['mc_gross']}', '{$_POST['txn_id']}', '{$_POST['receiver_email']}', '{$_POST['quantity']}', '{$_POST['payer_id']}', '{$_POST['receiver_id']}', '{$_POST['item_number']}', '{$_POST['payment_status']}', '{$_POST['custom']}', '{$_POST['charset']}', '{$_POST['notify_version']}', '$nlink')");

echo $sql;

$count=0;
$sql3=mysql_query("select * from indCredits where MemberID=$MemberID");
while( $row = mysql_fetch_array( $sql3 ) )
							{

							$oldcredits=$row['credits'];
							$count++;
							}

							$newcredits=$oldcredits+$_POST['quantity'];	

							if($count=='0')
							{

							$sql2="insert into indCredits (MemberID, credits) values ('$MemberID','$newcredits')";

							$rs2=mysql_query($sql2,$conn);

							}
							else
							{

							$sqlins=mysql_query("update indCredits set credits='$newcredits' where MemberID='$MemberID'");


							}




?> 

[frijole]

It would be helpful to post your code in the "code" brackets. Like this:

<?php

session_start();

$inDate=date("Y-m-d");
                        
$nlink=str_replace("'", "", $_POST['merchant_return_link']);
                     

$sql = mysql_query("INSERT INTO `credit_transaction` (`id`, `from_id`, `to_id`, `date`, `user_id`, `no_of_credits`, `payer_last_name`, `payer_first_name`, `residence_country`, `item_name`, `payment_gross`, `mc_currency`, `business`, `payment_type`, `payer_status`, `verify_sign`, `test_ipn`, `payer_email`, `tax`, `mc_fee`, `payment_fee`, `shipping`, `mc_gross`, `txn_id`, `receiver_email`, `quantity`, `payer_id`, `receiver_id`, `item_number`, `payment_status`, `custom`, `charset`, `notify_version`, `merchant_return_link`) VALUES ('', '0', '$MemberID', '$indate', '$MemberID', '{$_POST['quantity']}', '{$_POST['last_name']}', '{$_POST['first_name']}', '{$_POST['residence_country']}', '{$_POST['item_name']}', '{$_POST['payment_gross']}', '{$_POST['mc_currency']}', '{$_POST['business']}', '{$_POST['payment_type']}', '{$_POST['payer_status']}', '{$_POST['verify_sign']}', '{$_POST['test_ipn']}', '{$_POST['payer_email']}', '{$_POST['tax']}', '{$_POST['mc_fee']}', '{$_POST['payment_fee']}', '{$_POST['shipping']}', '{$_POST['mc_gross']}', '{$_POST['txn_id']}', '{$_POST['receiver_email']}', '{$_POST['quantity']}', '{$_POST['payer_id']}', '{$_POST['receiver_id']}', '{$_POST['item_number']}', '{$_POST['payment_status']}', '{$_POST['custom']}', '{$_POST['charset']}', '{$_POST['notify_version']}', '$nlink')");

echo $sql;
                        
$count=0;
$sql3=mysql_query("select * from indCredits where MemberID=$MemberID");
while( $row = mysql_fetch_array( $sql3 ) )
                        {
                        
                        $oldcredits=$row['credits'];
                        $count++;
                        }
                           
                        $newcredits=$oldcredits+$_POST['quantity'];   
                           
                        if($count=='0')
                        {
                        
                        $sql2="insert into indCredits (MemberID, credits) values ('$MemberID','$newcredits')";
                  
                        $rs2=mysql_query($sql2,$conn);
                  
                        }
                        else
                        {
                        
                        $sqlins=mysql_query("update indCredits set credits='$newcredits' where MemberID='$MemberID'");
                        
                        
                        }
                        



?>

[revraz]

Check and see how many rows are returned from this query

 

$sql3=mysql_query("select * from indCredits where MemberID=$MemberID");

 

[PFMaBiSmAd]

Your code is unconditionally executed any time that page is requested (assuming that is all the code on the page.)

 

There are a number of things a browser can do to cause a double-page request and a lot of url rewriting, both correct and incorrect, can cause a url to be requested more than one time.

 

So, you need to find out where the extra empty request for the page is coming from. You also need to add a conditional test to make sure the form was submitted and only execute the database code if it was. Also, setting a session variable that says the data has been processed in that session and checking this to prevent additional inserts after the first one would help.

[agravayne]

The query

 

$sql3=mysql_query("select * from indCredits where MemberID=$MemberID");

 

returns one row. Which is correct.

[agravayne]

mmm I can check the session variable and if its not there prevent a write to the database. That would solve this problem.

 

The original page was far more complicated but what I have posted here is a stripped down version and still has the same problem. Originally I had a query that would check that the $_POST['txn_id'] did not already exist in the database if it did to prevent the insert. However it still wrote twice.

 

I will try checking the session variable first though.