What is wrong with this foreach loop? - php

Question

I am trying to allow my users to update quantities in the database, by providing them some input fields, I know that the sql update query is perfect, because if i DONT use the foreach loop, it will submit and update the last textfield only.
But I need the foreach loop so it will loop through all the textfields and update them all in the database. Can somebody please help me figure out why it's not updating with this foreach loop? Lots of thanks in advance :)
foreach($_POST['items'] as $p=>$q)
{
// working sql code is in here.
}
And the fields are dynamically generated like so:
$ct->data[$key][0]='<input type="text" value="'.$ct->data[$key][0].'" name="product" />';
$ct->data[$key][1]='<input type="text" value='.$ct->data[$key][1].' id="qty" name="items[' . $ct->data[$key][1] . ']" />';
$ct->data[$key][2]='<input type="submit" value="Update Item">';
$ct->data[$key][3]='<p name="price">'.$ct->data[$key][3].'</p>';

Answer 1

You should ALWAYS check if a variable exists. That's no more that normal and should have been lession 1.
You can't iterate over $_POST['items'] if $_POST['items'] doesn't exist (obviously). So you have to check if the form has been submitted.
One way is:
if ( isset($_POST['items']) ) {
// foreach ( $_POST['items'] ....
}
I always like to be on the safe side and check for type as well:
if ( isset($_POST['items']) ) {
// form submitted at least
if ( is_array($_POST['items']) ) {
// and it's an array as it should be
foreach ( ....
}
}
POST variables are never set in a GET request, so doing the foreach first time on a page is useless. That's what the check is for: 'is the form submitted and do the necessary post vars exist?'

Answer 2

What values are you seeing?
foreach($_POST['items'] as $p=>$q) {
print "$p: $q\n";
}

Answer 3

The name of the items input field should just be items[].
So:
# Good
$ct->data[$key][1]='<input type="text" value='.$ct->data[$key][1].' id="qty" name="items[]" />';
# Bad
$ct->data[$key][1]='<input type="text" value='.$ct->data[$key][1].' id="qty" name="items[' . $ct->data[$key][1] . ']" />';