Help with PHP multiple select field

paligron · #1 (**permalink**) 10-23-09, 12:46 AM

Hi,
I have a script that updates a multiple select field. I would like it to do the following:
1. check to see if the submitted form has an empty multiple select field and return an error
2. On loading the update page, the previously selected items should be selected in the multiple select field.

Here is what I have so far but I keep on getting the Undefined Index error:

functions.php

PHP Code:


			
//----------Function for getting item accessories----------

function getAccessories()

{

    $sql = "SELECT accessories FROM tablename ORDER BY accessories"; 

    $res = mysql_query($sql);



    echo "<select name='accessories[]' size='4' multiple='multiple' class='input'><option value='-1'>------------------------</option>";

        while($row = mysql_fetch_row($res)) { 

            echo  "<option value='".$row[0]."'>".$row[0]."</option>";

            }

    echo "</select>";

}





//----------Function for updating item on mysql db----------

function updateItem($accessories,$id)

{

    if (empty($accessories)) {

        return 1;

          } else {                

        $sql = "UPDATE theitem SET item_accessories = '" . $accessories . "' WHERE item_id = " . $id . "";

        $res = mysql_query($sql); // or die(mysql_error());

        return 99;

        }

}

update.php

PHP Code:


			
require_once ('library/database.php');

include ('library/functions.php');

include ('library/english.php');

if (isset($_POST['update_item'])){

    $_POST = cleanCode($_POST);

    $serializedaccessories = serialize($_POST['accessories']);

        $res = updateItem($serializedaccessories,$_POST['item_id']);

        //if successful

        if($res == 99){

            $message = ITEM_EDITED;

            }

        //if errors occured

        if($res == 1){

            $error = EMPTY_FIELD;

        }

}

HTML Code:

<HTML>
<HEAD></HEAD>
<BODY>
    <form action="<?= $_SERVER['PHP_SELF']; ?>" method="post" name="fmpost">
		<input name="item_id" type="hidden" value="<?= $id; ?>" /> //$id got from a function
                <span class="error"><?php if(isset($error)){ echo $error;}?></span>
		<span class="message"><?php if(isset($message)){ echo $message;} ?></span>	
                <div><label for="accessories" class="label">Accessories:</label><br /><span class="smallText">Hold down CTRL key and click to select multiple.</span></div>
		<div><? getAccessories(); ?> </div>
                <div><input type="submit" name="update_item" value="Update" class="postbttn"/></div>
</BODY>
</HTML>

Please help

End User · #2 (**permalink**) 10-23-09, 07:14 AM

Quote:

Originally Posted by paligron

Here is what I have so far but I keep on getting the Undefined Index error

The Undefined Index error is telling you that some variable (an array) isn't being declared before use. You can resolve this by declaring all your variables, including arrays, before running any of the code.

wirehopper · #3 (**permalink**) 10-23-09, 08:46 AM

Add var_dump($_REQUEST); as the first line of your code. That will show you what is being sent from the client.

paligron · #4 (**permalink**) 10-23-09, 05:04 PM

the undefined variable is the 'accessories', which is the name of the input field. How do you define it as an array? I have tried to define it normally as an array but the submitted result is always empty.

End User · #5 (**permalink**) 10-23-09, 07:19 PM

Quote:

Originally Posted by paligron

the undefined variable is the 'accessories', which is the name of the input field. How do you define it as an array? I have tried to define it normally as an array but the submitted result is always empty.

"Undefined index" means the variable you are trying to use doesn't exist (when your variable is not properly set). One way to handle this issue is to check if $_POST['action'] is set before using it. For example:

PHP Code:


			
if (!isset($_POST['action'])){



//If not isset -> set with dummy value

$_POST['action'] = "undefine";



}

job0107 · #6 (**permalink**) 10-24-09, 12:07 AM

I changed your getAccessories() and updateItem() functions.
functions.php

PHP Code:


			
//----------Function for getting item accessories----------
function getAccessories()
{
 $sql = "SELECT accessories FROM tablename ORDER BY accessories";
 $res = mysql_query($sql);
 echo "<select name='accessories[]' size='4' multiple='multiple' class='input'><option value='-1'>------------------------</option>";
 while($row = mysql_fetch_row($res))
 {
  if(!empty($_POST['accessories']))
  {
   if(in_array($row[0],$_POST['accessories'])){echo  "<option value='".$row[0]."' selected>".$row[0]."</option>";}
   else{echo  "<option value='".$row[0]."'>".$row[0]."</option>";}
   }
  else{echo  "<option value='".$row[0]."'>".$row[0]."</option>";}
  }
 echo "</select>";
 }

//----------Function for updating item on mysql db----------
function updateItem($accessories,$id)
{
 $sql = "UPDATE theitem SET item_accessories = '" . $accessories . "' WHERE item_id = " . $id . "";
 $res = mysql_query($sql); // or die(mysql_error());
 }

And I modified your update.php code.

PHP Code:


			
<?php
require_once ('library/database.php');
include ('library/functions.php');
include ('library/english.php');
$message = "";
if(!empty($_POST['update_item']))
{
 if(empty($_POST['accessories']) || ($_POST['accessories'][0] == -1 && empty($_POST['accessories'][1])))
 {
  $message = "EMPTY_FIELD";
  $class = "error";
  }
 else
 {
  if($_POST['accessories'][0] == -1){array_shift($_POST['accessories']);}
  $_POST = cleanCode($_POST);
  $serializedaccessories = serialize($_POST['accessories']);
  updateItem($serializedaccessories,$_POST['item_id']);
  $message = "ITEM_EDITED";
  $class = "message";
  }
 }
?>
<HTML>
<HEAD></HEAD>
<BODY>
    <form action="#" method="post" name="fmpost">
     <input name="item_id" type="hidden" value="<?php echo $id; //$id got from a function ?>" />
     <?php if($message){echo "<span class='$class'>$message</span>";} ?>    
     <div><label for="accessories" class="label">Accessories:</label><br /><span class="smallText">Hold down CTRL key and click to select multiple.</span></div>
     <div><?php getAccessories(); ?> </div>
     <div><input type="submit" name="update_item" value="Update" class="postbttn"/></div>
    </form>
</BODY>
</HTML>

paligron · #7 (**permalink**) 10-25-09, 02:00 AM

Yup. Thank you guys. Your help is highly appreciated. Job, wrapping ones head around all those if statements, especially for a php newbie like me, is mind tiring. But I understand the concept now. You have also fully answered my original question. I am now on the right track. Thanks a milli.

job0107 · #8 (**permalink**) 10-25-09, 11:30 PM

Quote:

Originally Posted by paligron

Yup. Thank you guys. Your help is highly appreciated. Job, wrapping ones head around all those if statements, especially for a php newbie like me, is mind tiring. But I understand the concept now. You have also fully answered my original question. I am now on the right track. Thanks a milli.

Understanding the logic flow is 3/4th the battle in creating any program.
Learning the syntax of the language you wish to program in, is the other 1/4.

So, when you have a problem that seems too difficult to figure out, stop and create a flow chart that describes the program flow.
Once you understand what you have to do to make the program work, figuring out the right commands to use becomes much simpler.

job0107 · #9 (**permalink**) 10-26-09, 12:18 AM

I found an error in your updateItem() function and corrected it.
The error was in the quoting of the $id varable.

PHP Code:


			
<?php
//----------Function for updating item on mysql db----------
function updateItem($accessories,$id)
{
 mysql_query("UPDATE theitem SET item_accessories = '".$accessories."' WHERE item_id = '".$id."'");
 }
?>

paligron · #10 (**permalink**) 10-26-09, 01:46 AM

It is now working perfectly. I also noticed that the key to the message/error displays lay with the 'in_array' function. Thanks again. This thread can now be closed. Unfortunately, I must claim ignorance as I don't know how to close this thread.