PHP newbie seeking advice in coding inventory quantities

Skazz

Hi there! I’m driving myself mad trying to modify a piece of php code provided to me by my shopping cart developer as they are currently very busy, but unfortunately I have no experience with php, as I’ve only ever dealt with html before. The code is designed to call the database of products upon an item being added to the cart in order to remove one from the backend inventory.

The code I began with is this:

<?php
$HTML = "";
// Get all specific result from the "inventory" table
$result = mysql_query("SELECT * FROM inventory WHERE catagory='catname'") or die(mysql_error());  

while($row = mysql_fetch_array($result)){
    if($row['instock'] != 0){

$HTML .= <<< eof
<option cost="$row[listPrice]" id_num="$row[itemid]" name="$row[itemName]">$row[description]</option>
eof;
}
}
echo $HTML;


?>

However, I don’t want customers to be able to add items to cart if the ‘instock’ number is 0 or less (because we won’t have any to sell!) With my limited understanding and some research, I think I need to add an else or elseif statement somewhere in here, along the lines of

elseif($row['instock'] <= 0)
{
echo 'Sorry this item is out of stock.'
}

However, wherever I seem to put it I always end up with a syntax error whenever I try to run the script. I have tried to figure out how all the braces work and $HTML but I’m totally lost!

I’m also wondering if I need something extra in there since each item has a text-entry quantity box that is completed before the item(s) are added to the cart, so I think something might be needed to be added so that if a customer enters a number in the box that is more than is in stock and clicks ‘add to cart’, they’ll have some kind of popup to tell them they’ve chosen more than is currently available. If so, I’d love some advice on how to do this also!

Thanks in advance!

Res

I'll help you out with this issue, but I think you want to go back to the drawing board on how you want to handle this.

Let's say I'm just shopping around and add a bunch of things to my cart, I have no intention of buying them. Now the next customer comes around and isn't allowed to purchase something because it's in my cart causing the avail qty to drop to or below 0. Generally you don't want to remove something from inventory until it's left the warehouse. This is usually handled by onhand and onorder quantities to calculate the available.

Any how, I strongly recommend you rethink subtracting inventory prior to an order being fulfilled or even officially hitting the books, here is how you would add that elseif statment. Even my suggestion of onorder incrementing should only be done once the order is processed, I wouldn't even let declined orders eat inventory.

I think you had an extra curly brace and a missing semi colon. It also looks like putting the logic in this place won't acheive what you want, this bit you posted appears to be getting products by their category name. You want the logic check prior to adding the item to the shopping cart.

<?php
$HTML = "";
// Get all specific result from the "inventory" table
$result = mysql_query("SELECT * FROM inventory WHERE catagory='catname'") or die(mysql_error());
while($row = mysql_fetch_array($result)){
	if($row['instock'] > 0){

	$HTML .= <<< eof
<option cost="$row[listPrice]" id_num="$row[itemid]" name="$row[itemName]">$row[description]</option>
eof;
	}elseif($row['instock'] <= 0)
	{
		echo 'Sorry this item is out of stock.';

}
echo $HTML;


?>

Just noticed something I fixed in the example above, it was checking to see if instock was not equal to 0, it should be > 0 so that 0 or negative numbers (seen them in LOTS of inventory systems) will triggert out of stock.

Skazz

Hi Res,

Thanks so much for your help and speedy reply!

You are absolutely right in not wanting items removed from inventory before they’ve actually been purchased! However after a quick test using a demo page from my site it seems that no number change to the back end inventory is occurring until the customer has checked out, so no worries there.

During my test, I increased the inventory so that each product had 5 items in stock (it was at –1), however following the purchase process being carried through, instead of decreasing to 4 it dropped back to –1 again in the backend, so I’m not quite sure what’s going on there, but this might be a question for the developer.

I did however input the code you so kindly provided, however I received this message:

Parse error: syntax error, unexpected $end in /home/fhlinux150/b/bedlamitesboutique.co.uk/user/htdocs/_jewellery2.php on line 443

It’s possible I pasted it in incorrectly – the code for the shopping cart/items is as follows (apologies for the length!):


<!--Shopping Cart Begin-->
<p>
<form name="order" action="/cart/sc-managecart.html">
<input type="hidden" name="PRICE" value="" />
<input type="hidden" name="NAME" value="Bottle Pendant" />
<input type="hidden" name="ID_NUM" value="BTP" />
<input type="hidden" name="WEIGHT" value="1" />
<span style="white-space:nowrap;">Select a Bottle Type
<select name="PRODUCTSELECTOR">

<?php
$HTML = "";
// Get all specific result from the "inventory" table
$result = mysql_query("SELECT * FROM inventory WHERE catagory='Bottle Type 1'") or die(mysql_error());
while($row = mysql_fetch_array($result)){
    if($row['instock'] > 0){

    $HTML .= <<< eof
<option cost="$row[listPrice]" id_num="$row[itemid]" name="$row[itemName]">$row[description]</option>
eof;
    }elseif($row['instock'] <= 0)
    {
        echo 'Sorry this item is out of stock.';

}
echo $HTML;


?> 
</select></span>
<span style="white-space:nowrap;">Select Bottle Contents 
<select name="ADDITIONALINFO">

<option value="Liquid">Liquid</option>
<option value="Glowing Crystals">Glowing Crystals</option>
</select></span>
<br /><span style="white-space:nowrap;">
Quantity: <input type="number" min="1" max="10" step="1" size="3" maxlength="3" name="QUANTITY" onChange='this.value=CKquantity(this.value)' value="1" />
</span><br /><span style="white-space:nowrap;"><img src="SPACER.GIF" width="120" height="10" /><input type="button" value=" Add to Cart " align="top" onClick="AddOneOfManyToCart(this.form);" />
<a href="/cart/sc-managecart.html">View Cart</a></span>
</form>
<!--Shopping Cart End -->

<!--Shopping Cart Begin-->
<p>
<form name="order" action="/cart/sc-managecart.html">
<input type="hidden" name="PRICE" value="12.00" />
<input type="hidden" name="NAME" value="spangly" />
<input type="hidden" name="ID_NUM" value="S1" />
<input type="hidden" name="WEIGHT" value="1" />


<?php
$HTML = "";
// Get all specific result from the "inventory" table
$result = mysql_query("SELECT * FROM inventory WHERE catagory='Spangly'") or die(mysql_error());
while($row = mysql_fetch_array($result)){
    if($row['instock'] > 0){

    $HTML .= <<< eof
<option cost="$row[listPrice]" id_num="$row[itemid]" name="$row[itemName]">$row[description]</option>
eof;
    }elseif($row['instock'] <= 0)
    {
        echo 'Sorry this item is out of stock.';

}
echo $HTML;


?> 

Quantity: <input type="number" min="1" max="10" step="1" size="3" maxlength="3" name="QUANTITY" onChange='this.value=CKquantity(this.value)' value="1" />
</span><br /><span style="white-space:nowrap;"><img src="SPACER.GIF" width="120" height="10" /><input type="button" value=" Add to Cart " align="top" onClick="AddToCart(this.form);" />
<a href="/cart/sc-managecart.html">View Cart</a></span>
</form>
<!--Shopping Cart End -->

                </FONT>
                </TD></TR>

              </DIV>


        </td>
      </tr>
    </table>
  </BODY>

</HTML>

Hope this all makes sense, thanks again for your help, and I look forward to hearing what mistake I’ve made :o