Question

An array creates by this:

<input type="checkbox" name="transport[]" value="0">Taxi
<input type="checkbox" name="transport[]" value="1">Bus
<input type="checkbox" name="transport[]" value="2">Train

Although the checkbox only comes if its true(if its checked), so only the checked checkboxes will be passed.

Now I am trying to do so that the checkboxes that gets passed(the ones that are checked), should insert a row in table transports and the checkboxes that are not checked(not gets passed) should delete. And if it already is inserted, it should not do anything.

So:

• Check if its already inserted before
• Insert new row in transports
  for the checkboxes passed
• Delete the
  rows for the checkboxes that didnt
  pass

I tried doing this:

    $transport = $_POST["transport"]; // variable receiving

    for($u=0; $u<3; $u++){ // taxi, bus and train (3)
         if($u == $transport[$u]){ 
            $alreadyExists = $connect->prepare("SELECT id FROM transport WHERE xID=:xID AND transport=:t");
            $alreadyExists->bindValue(":t", $u);
            $alreadyExists->bindValue(":xID", $cID);
            $alreadyExists->execute();
            $alreadyExists = $alreadyExists->rowCount();
            if($alreadyExists == 0){ // if it doesnt exists, insert into
          $updateTransport = "INSERT INTO transport (xID, transport) VALUES (:id, :t)";
          $updateTransport = $connect->prepare($updateTransport);
          $updateTransport->bindValue(":id", $cID);
          $updateTransport->bindValue(":t", $u);
          $updateTransport->execute();
            }
         }else{ // delete row as it is not checked
          $updateTransport = "DELETE FROM transport WHERE xID=:id AND transport=:t";
          $updateTransport = $connect->prepare($updateTransport);
          $updateTransport->bindValue(":id", $cID);
          $updateTransport->bindValue(":t", $u);
          $updateTransport->execute();
         }
    }

But It wont work properly, I receive undefined offset 2, 1 I cant figure out why

What have I done wrong? How can I make it work properly?

Answer 1

you should do somethign like:

<input type="checkbox" name="transport[tax]" value="1">Taxi
<input type="checkbox" name="transport[bus]" value="1">Bus
<input type="checkbox" name="transport[train]" value="1">Train

and

$toDelete = array('taxi'=>true,'bus'=>true,'train'=>true);  
foreach($_POST['transport'] as $k=>$v) {
  //> Insert $k

  $toDelete[$k]  = false;
}

foreach($toDelete as $k=>$v) {
   if ($v===true) {
    //> delete $k here
   }
}