Inserting when NULL

[RynMan]

Hey guys

So I've built a form with various text fields, radio buttons, and text areas. Now I want to be able to use the data collected from that form and INSERT it into my table using PHP.

On the next page (the action=) page from my form, I set up the INSERT query, however it runs into a problem when I don't enter a value into a field on the form on the previous page.

It's because I'm using the $variable = $_POST["postedvariable"] method, and since nothing was entered, nothing is posted, and the query fails since there is no value.

I'm wondering how this is usually handled in PHP? Do you have to write 'if statements' to handle it?

Thanks for any help guys!

[ixalmida]

The only form field which won't POST to the next page would be a checkbox (if not checked). Otherwise, all form fields will POST, even if they are empty.

For example, if textbox1 is left blank, you get the variable $POST['textbox1'] with the value of "". But if checkbox1 is not checked, then $POST['checkbox1'] does not exist.

To avoid errors, use:

if(isset($_POST['checkbox1']))
  $checkbox1 = $_POST['checkbox1'];
else
  $checkbox1 = NULL;

Or shorthand:

$checkbox = isset($_POST['checkbox1']) ? $checkbox1 : NULL;

Unfortunately, if you have a lot of checkboxes, this is going to get quite messy.

It would probably be best to use arrays of checkboxes in this case, ie:

<input type="checkbox" name="checkbox1[]" value="1">
<input type="checkbox" name="checkbox1[]" value="2">
<input type="checkbox" name="checkbox1[]" value="3">

Then you can use foreach() loops to see which checkboxes are checked:

// I can't remember if you need the brackets after checkbox1 here, so try both ways...
$ck1 = $_POST['checkbox1[]'];

foreach($ck1 as $value)
  {
  echo "Checkbox $value checked!<br>";
  }

[bradgrafelman]

Just to add on; the brackets aren't used in the PHP code as the form elements will be converted into an array automagically by the PHP parser.

In other words, $_POST['checkbox1'] will be an array if you use ixalmida's suggestion.

Note that we would be able to help you find the best solution if you also post your SQL table structure (and perhaps an example INSERT query).

[ixalmida]

Thanks for the assist. It has been a while since I had a bunch of checkboxes to deal with. I've been pulling my hair out due to a server upgrade so I can't spend as much time here as I'd like either.

If anyone ever has a chance to query a remote Advantage DB from a 'nix box...RUN!

:glare: