Making a checkbox recognize its intended data

Question

Level: PHP Learner

I'm stuck with a checkbox problem. I have a db that contains names and unique id numbers.

Using a query, I am pulling a selection of students and showing them to a user in an ultra simple HTML table on a form. Each row begins with a checkbox. The method is POST. So far, so good. My table kinda looks like this:

+-----------+----------+----------+
|   SELECT  |    NAME  |    ID    |
+-----------+----------+----------+
|   []      |    John  |    2233  |
+-----------+----------+----------+
|   []      |    Susie |    5577  |
+-----------+----------+----------+

[-SUBMIT-]

My problem is that I cannot seem to make the checkbox associate with each record's unique ID. Once the user has selected rows and clicked submit, the $_POST array remains empty.

None of my beginners books reference this specific issue. They go through the "regular" checkbox routines that don't involve interacting with rows from a db. I also could not find an issue on Stackoverflow that addresses this. Also tried Google: plenty of stuff on checkboxes, but I couldn't find any that helped me on this problem.

Thanks.

Answer 1

Just do something like this:

<input type="checkbox" name="ids[]" value="2233" /> ... rest of row
<input type="checkbox" name="ids[]" value="5577" /> ... rest of row

Now, in PHP, you can get the selected ids like this:

$ids = $_POST['ids'];
if( empty($ids) ) $ids = array();

This sets $ids to an empty array if the form was submitted without any of the checkboxes checked.

Answer 2

Edit: If your form doesn't get more complex as you describe, take Doug Neiner's approach, as it is way simpler. This approach is right if a table is likely to have a number of columns.

I like to do it this way:

Number the checkboxes sequentially (1 to 100) and add a hidden field connecting the row number to a real database ID:

<input type="checkbox" name="row_1" value="checked">`
<input type='hidden' name='row_1_id' value='2233'>`

Store the total number of rows in another hidden field

<input type='hidden' name='row_total' value='99'>

Then, in the receiving script, iterate from 1 to the total number of rows using for, check whether this row was selected, and get the associated database ID:

for ($i = 1; $i <= $number_of_rows; $i++)
{
  if ($_POST["row_$i"] == "checked")
   {
     $database_id_unsafe = $_POST["row_{$i}_id"];
 ...

the latter, of course, needs to be properly sanitized and escaped in case it is processed further.