arrays confusion

[dbdummy]

hi, I have a form that uses two arrays one get's a list of courses from the database and one creates dates...

i have two questions

1. how do i get the $i and $d value off of the arrays to insert in to the database, but still have each know they belong in the same row?

2. how do i change the dates from a multiselect dates ie, Jun 3, Jun 6, and Jun 12 to 'Jun 3, 6, 12'

here is the snippet of code from my select page. $numposts is a value selected on an earlier page.

for ($i = 0; $i < $numposts; $i++){
echo "<tr> 
      <td><strong>Course</strong></td>
      <td>";
$query_course = "SELECT * FROM courses ORDER BY course_number";
$course = mysql_query($query_course) or die(mysql_error());
if (!$result) 
{
}
echo "<select name='$session_course$i' id='$session_course$i'>
          <option selected='selected'>Select Course</option>";

while ($row_course = mysql_fetch_assoc($course))
{
$cnumber=$row_course['course_number'];
$cnumberid=$row_course['course_id'];
          echo "<option value='$cnumberid$i'>$cnumber</option>";

}
echo "</select></td>
      <td> 
        <select name='session_dates$i' id='session_dates$i' multiple='multiple' size='4'>
          <option selected='selected'>Select Date(s)</option>";

$date = mktime(0,0,0);
for ($d=0; $d<365; $d++)
{
    $d1 = date('M d Y', $date);
    $d2 = date('M d Y', $date);
    echo "<option value='$d1$d'>$d2</option>\n";
    $date = strtotime('+1 days', $date);
}

    echo "</select></td>";
	}

below is currently is my insert statement...but currently gets the error message:

Cannot add or update a child row: a foreign key constraint fails (prosched/prodates, CONSTRAINT prodates_ibfk_3 FOREIGN KEY (session_course_id) REFERENCES courses (course_id))

$dsessioncourse = $_POST["date_session_id"];
$citycourse = $_POST["session_city_id"];
$monthcourse = $_POST["session_month_year_id"];
$activecourse = $_POST["session_ative"];
$loop = count($_POST) / 2;

for ($i = 0; $i < $loop; $i++) {
if($_POST["session_course$i"]) $product[$i]["session_course"] = $_POST["session_course$i"];
}
for ($d = 0; $d < $loop; $d++) {
if ($_POST["$d1$d"]) $product[$d]["session_dates"] = $_POST["$d1$d"];
}
foreach ($product as $item) {
$course = $item["session_course"];
$sessiond = $item["session_dates"];


$query = mysql_query("INSERT INTO `prodates` (`date_session_id`, `session_month_year_id`, `session_dates`, `session_active`, `session_city_id`, `session_course_id`) 
VALUES ('$dsessioncourse', '$monthcourse', '$session_d', '$activecourse', '$citycourse', '$course')") or die(mysql_error()); 

}

[sneakyimp]

You need to work on indenting your code. It's almost impossible to read without whitespace formatting. Also, use PHP tags rather than CODE and you'll get colored formatting for the code.

What you show is not your insert statement but the resulting error. Sounds like your db has foreign key constraints which are violated by your insert attempt. This happens when you try to create a new record with a value that's supposed to point to a value in some other table and there is no corresponding record in that other table.