Explain this code to me, please

swifttide

OK, I had an issue I couldn't fix, so I had someone write the code for me. Unfortunately, he didn't comment it, and I don't know what it does!! Can someone help??

What I want to do, before I do the insert, is to query the table and see if that record already exists. But I can't tell (for instance, if I just wanted to check student_schedule_id, how would I know what that is? How would I echo only that field to the screen??)

Thanks to anyone who can help!

Here's the code:

<?php

include_once "ez_sql.php";

$clear = $POST['clear'];
reset($clear);
echo('Schedule ID -> ' . substr($POST['id'],0,strlen($POST['id'])-4) . ' ');
foreach($clear as $clr)
{
if($clr==1)
{
$query = "INSERT INTO student_schedule(student_schedule_id,student_schedule_studentid,student_schedule_year,student_schedule_schoolid,student_schedule_schedid)
VALUES(0," . key($clear) . ",0,0," . substr($POST['id'],0,strlen($_POST['id'])-4) . ");";
echo($query." ");
$db->query($query);
//echo('Student ID -> ' . key($clear) . '... to be inserted ');
}
next($clear);
}

Oni

If you want to check if the value of "student_schedule_id" try something like this:

// form and execute query statement
$query = "SELECT student_schedule_id FROM table WHERE student_schedule_id=$id ";
$result = mysql_query($query) or die(mysql_error());
if (mysql_num_rows($result) == 0) { // If nothing found
print "No student with that id number exists!"; }
else { //Someone by that id already in table
print "A student with that id number exists!"; }

swifttide

Yup, I think I can do that. I guess my question was, he appears to build an array in that code, as best as I can tell from the portion of the POST statement:

echo('Schedule ID -> ' . substr($POST['id'],0,strlen($POST['id'])-4) . ' ');

My question is, how would I take apart the array? To make sure there are no duplicate entries, I would need to check all the fields. I have tried $POST[0], $POST[1], etc, but that doesn't seem to do it.

Doug