Set update form checkbox array to 0 instead of NULL - php

Question

I have a update form that populates from a database dynamically, I have two checkboxes in my form that post to an array so I can hit one submit button and update all rows with a foreach statement. The text fields work as they should, but when the checkbox fields post to their array, they leave out the zeros my arrays become shorter.
How do I add 0 where a null checkbox would be?
this is my form
<form action="<?php echo $editFormAction; ?>" method="post" name="form1" id="form1">
<input type="hidden" name="ss_id[]" value="<?php echo $row_rsSnapshot['ss_id']; ?>" />
<input type="hidden" name="ss_yearmonth[]" value="<?php echo htmlentities($row_rsSnapshot['ss_yearmonth'], ENT_COMPAT, 'UTF-8'); ?>" />
<tr>
<td>
<input <?php if (!(strcmp($row_rsSnapshot['ss_inventory'],1))) {echo "checked=\"checked\"";} ?> type="checkbox" name="ss_inventory[]" value="" <?php if (!(strcmp(htmlentities($row_rsSnapshot['ss_inventory'], ENT_COMPAT, 'UTF-8'),""))) {echo "checked=\"checked\"";} ?> />
</td>
<td>
<input <?php if (!(strcmp($row_rsSnapshot['ss_write_off'],1))) {echo "checked=\"checked\"";} ?> type="checkbox" name="ss_write_off[]" value="" <?php if (!(strcmp(htmlentities($row_rsSnapshot['ss_write_off'], ENT_COMPAT, 'UTF-8'),""))) {echo "checked=\"checked\"";} ?>
</td>
<td>
<input type="text" name="ss_date[]" value="<?php echo htmlentities($row_rsSnapshot['ss_date'], ENT_COMPAT, 'UTF-8'); ?>" size="32" />
</td>
<td>
<input type="text" name="ss_transaction[]" value="<?php echo htmlentities($row_rsSnapshot['ss_transaction'], ENT_COMPAT, 'UTF-8'); ?>" size="32" />
</td>...
And here is my sql update query
foreach($_POST['ss_id'] as $key=>$ss_id){
$ss_inventory = GetSQLValueString(isset($_POST['ss_inventory'][$key]) ? "true" : "", "defined","1","0");
$ss_write_off = GetSQLValueString(isset($_POST['ss_write_off'][$key]) ? "true" : "", "defined","1","0");
$ss_date = $_POST['ss_date'][$key];
$ss_transaction = $_POST['ss_transaction'][$key];
$ss_debit = $_POST['ss_debit'][$key];
$ss_credit = $_POST['ss_credit'][$key];
$ss_yearmonth = $_POST['ss_yearmonth'][$key];
$sql = "UPDATE snapshot SET ss_inventory = '$ss_inventory', ss_write_off = '$ss_write_off', ss_date = '$ss_date', ss_transaction = '$ss_transaction', ss_debit = '$ss_debit', ss_credit = '$ss_credit' , ss_yearmonth = '$ss_yearmonth' WHERE ss_id = '$ss_id' ";
mysql_select_db($database_connMyayla, $connMyayla);
$Result1 = mysql_query($sql, $connMyayla) or die(mysql_error());
}
}
mysql_close();
?>

Answer 1

this solved it
If anyone is interested...
I put a counter to find out how many rows are being populated with this query and inserted that into my checkbox name array...
$i = 0;
do {
...
<td>
<input <?php if (!(strcmp($row_rsSnapshot['ss_inventory'],1))) {echo "checked=\"checked\"";} ?> type="checkbox" name="ss_inventory[<?php echo $i;?>]" value="" <?php if (in_array($i, $ss_inventory)) echo "checked='checked'"; ?> />
</td>
<td>
<input <?php if (!(strcmp($row_rsSnapshot['ss_write_off'],1))) {echo "checked=\"checked\"";} ?> type="checkbox" name="ss_write_off[<?php echo $i;?>]" value="" <?php if (in_array($i, $ss_write_off)) echo "checked='checked'"; ?> />
</td>
....
$i++;
} while ($row_rsSnapshot = mysql_fetch_assoc($rsSnapshot));
now the checkboxes that are checked will correspond with the correct array number..
e.g.
lets say you have 4 rows of data, but you only check the checkboxes for row 2 and 4.
//run this to see your result
print_r($_POST['ss_inventory']);
//outputs: Array ([1] => [3] =>)
Before this was my output, everything was pushed up to the start of my array because the false checkboxes were not being submitted or NULL. so rows 1 and 2 would result true.
//outputs: Array ([0] => [1] =>)
Also See
Checkbox "checked"-value jumps up to earlier array values, when array is empty

Answer 2

The browser does not submit unchecked checkboxes. You'll need to either give unique names, or simply use radio buttons.