Is this a sensible form iteration pattern for a web form with an unknown number of fields?

Question

I'm designing a small intranet-based time-tracking web app that accepts an unknown number of data "rows" which each consist of 7 form fields. Rows can by dynamically added by the browser.

Can I do better?

Given this (partial) example POST data:

$_POST['project'] => 
 Array
 (
 [0] => PROJECT_CODE_1
 [1] => PROJECT_CODE_1
 )
$_POST['task'] 
 Array
 (
 [0] => 21
 [1] => 4
 )
$_POST['date'] 
 Array
 (
 [0] => 2012年07月31日
 [1] => 2012年07月31日
 )

And this iterator:

<?php
$insert_values = array();
for ($i = 0; $i < count($_POST['project']); $i++)
{
 $insert_values[] = array(
 'entry_id' => null,
 'user_id' => $this->session->userdata('user_id'),
 'project_id' => $_POST['project'][$i],
 'task_id' => $_POST['task'][$i],
 'date' => $_POST['date'][$i]
 );
}
$this->db->insert_batch('entries', $insert_values);
?>

In general, is this iteration pattern safe and sensible? POST['project'] is a drop-down, is validated and will always be filled.

Answer 1

is this iteration pattern safe?

Safe for what? Safe for a database? We can't tell you that! There's no code for your database entry function. What you have here is perfectly safe, but that's excluding any type of insert into a database. To safely protect yourself from SQL injection and other types of security exploits, use prepared queries, validate (sanitize only if needed) incoming data (which includes the username and $_POST['project']!), and encode any output.

Without your database function, it's difficult to critique your code. There's not too much that be be done wrong in the snippet provided.