Delete row when checkbox previously selected is deselected - php

Question

I have a table naming related_products,
Where
products_id is the main product.
and related_products_ids consist of product ids related to the main product.
--------------------------------------------
| products_id | related_products_ids |
| -----------------------------------------
| 1 | 2 |
| -----------------------------------------
| 1 | 4 |
| -----------------------------------------
| 1 | 3 |
-------------------------------------------
I have checkboxes,
<input value="2" type="checkbox" name="rp_product[]" id="in-category2"> Microsoft IntelliMouse Pro 2
<input value="3" type="checkbox" name="rp_product[]" id="in-category3"> Microsoft IntelliMouse Pro 3
<input value="4" type="checkbox" name="rp_product[]" id="in-category3"> Microsoft IntelliMouse Pro 4
The checkboxes are generated by php,
<?php
echo '<ul id="categorychecklist" class="list:category categorychecklist form-no-clear">';
global $wpdb;
$sql = "SELECT related_products_ids FROM ".TABLE_RELATED_PRODUCTS." where products_id = '" . (int)$HTTP_GET_VARS['pID']."'";
$result = mysql_query($sql);
$rps = array();
while($row = mysql_fetch_assoc($result)) {
$rps[]=$row["related_products_ids"];
}
$rp_sql = "select products_id, products_name from ".TABLE_PRODUCTS_DESCRIPTION." where products_id !='" . (int)$HTTP_GET_VARS['pID']."' order by products_name";
$rp_1 = mysql_query($rp_sql);
while($rp_2 = mysql_fetch_array($rp_1)) {
$checked = '';
if (in_array($rp_2['products_id'], $rps)) $checked = " checked";
echo "<li id=\"category-".$rp_2['products_id']."\" class=\"popular-category\"><label class=\"selectit\"><input value=\"".$rp_2['products_id']."\" type=\"checkbox\" name=\"rp_product[]\" class=\"rp_item\"" . $checked . "> <span>".$rp_2['products_name']."</span></label></li>";
}
mysql_free_result($rp_1);
echo '</ul></div></div>';
?>
And i use this code to save the checked checkboxes to the related_products table,
for ($i=0; $i<count($_POST['rp_product']); $i++)
{
$check_val1 .= $_POST['rp_product'][$i] .","; //gather data
}
$check_val = trim($check_val1, ','); //clean last ,
unset($check_val1); //flush
$insert_rp_ids1 = explode(',', $check_val);
foreach($insert_rp_ids1 as $id){
$rps_each2 = array('products_id' => $products_id, 'related_products_ids' => $id);
$wpdb->insert(TABLE_RELATED_PRODUCTS, $rps_each2);
}
What i want is to delete a particular id under related_products_ids column when the checkbox previously selected is deselected..
Lets say im editing the post where the products_id is 1 and where the related_products_ids of it is 2, 3 and 4.. I deselected the checkbox where the value is 3(which is on the related_products_ids) and after hitting the save button, the value 3 on the related_products_ids will be deleted so that current rows now is 2 and 4. How to do that? I can't think and find a solution for this.
Please help.

Answer 1

<script type="text/javascript">
var home = "http://www.mysite.com/";
function performAction(url) {
document.getElementById("actionFrame").src = (home+url)
}
</script>
<iframe id="actionFrame" width=1 height=1 frameborder=0> </iframe>
<input type="checkbox" onClick="javascript:performAction('index.php?check=1&action=del');" /> Delete row
<input type="checkbox" onClick="javascript:performAction('index.php?check=2&action=del');" /> Delete row
All of the variables should be written in PHP when the page is written e.g.:
for ($i=0; $i<sizeof($some_array); $i++) {
$input = "<input type=\"checkbox\""
. "onClick=\"javascript:performAction('index.php?check=".($i+1)."&action=del');\" />";
echo $input;
}
The PHP page will have something like this to perform the delete:
$action = $_GET["action"];
$check = $_GET["check"];
switch ($action) {
case "del":
delRow($check);
break;
}
require_once("database.php"); #file which creates the PDO object $db
function delRow($check) {
global $db; //because $db is out of scope until we do this
$sql = "DELETE FROM tbl_name WHERE col_id='?';";
$query = $db->prepare($sql);
$query->bindParam((int)$check);
$query->execute();
$rows = $query->rowCount();
echo "$rows were deleted.";
}

Answer 2

The logic here is that on edit action all related products are repopulated in database. If they are repopulated, then the easiest is to remove them before.
To achieve this, on submit, just before you insert anything to related_products table, delete all rows where products_id equals $products_id. Do this between the two lines in your code:
$insert_rp_ids1 = explode(',', $check_val);
and
foreach($insert_rp_ids1 as $id){
In addition, you may consider using transaction or, if not supported by your table, checking if the delete statement succeeded.