Question

I am currently populating an array with checkboxes, imploding the array variable and using that variable in an IN clause within a DELETE function. var_dump is showing that I am creating a correct query, yet I can’t get any deletion to occur. This is a new approach to an existing problem I have had for a month or so.

Here’s what I have.

//Connect to the db
$id_array = NULL;

// Make the query to display user's uploads
 $q = "SELECT upload_id, title, genre, length, created, views
        FROM upload
        WHERE owner_id =". $_SESSION['user_id'] ."
        ORDER BY title ASC";


$r = mysqli_query ($dbc, $q); // Run the query

if($r)
    {
        // If it ran okay, display the records
        echo '<table align="center"
            cellspacing="3" cellpadding="3"
            width="75%">
           <tr><td align="left"><b>Title</b></td>
           <td align="left"><b>Genre</b></td>
           <td align="left"><b>Pages</b></td>
           <td align="left"><b>Submitted</b></td>
           <td align="left"><b>Views</b></td>
           </tr>';

        // Fetch and print all the records:
?><form action="/nbproject/newwriter_profile.php" method="post">
<?php
  while ($row = mysqli_fetch_array($r,MYSQLI_ASSOC))
    {
       echo '<tr><td align="left">' .
       $row['title'] . '</td><td align="left">'
       . $row['genre'] . '</td><td align="left">'
       . $row['length'] . '</td><td align="left">'
       . $row['created'] . '</td><td align="left">'
       . $row['views'] . '</td><td align="left">' //. var_dump($row) //dump row value for testing
       . '<input type="checkbox" name="checkbox[]"  value= "'.$row['upload_id'].'"'.' />'.' </td>'. '</tr>';
    }
   echo '</table>'; // Close the table
        ?>

the above code creates a simple table, each record is shown with a corresponding checkbox, check to delete then click “Delete”

         <input type="submit" name="delete" value="Delete" align="right"/> 
       </form>

<?php
   } // End of if ($r) IF.
    mysqli_close($dbc); // Close the database connection

custom delete function:

function submit_delete() {
  if(!is_null($_POST['delete']) && !is_null($_POST['checkbox'])) { //Check to see if a delete command has been submitted.
    //This will dump your checkbox array to your screen if the submit works.
    //You can manually check to see if you're getting the correct array with values
   // var_dump($_POST['checkbox']);//Comment this out once it's working.
    $id_array = $_POST['checkbox'];
    $id_array = array_map('intval', $id_array);
    $id_array = array_unique($id_array);
    $id_array = implode(',',$id_array);
    //var_dump($id_array);
    deleteUploads($id_array);

  }
  else {
    echo "Error: submit_delete called without valid checkbox delete.";//var_dump($_POST['checkbox']);
  }
}

$delete_success = false;
function deleteUploads ($id_array) {
    require_once(my connection to db);

    mysqli_free_result($r);

  if (count($id_array) <= 0) {   echo "Error: No deletes in id_array!"; echo 'wtf'; }

  //var_dump($id_array);

above var dump shows correct id’s as shown in my mysql database

    $gone = "DELETE  FROM `upload` WHERE `upload_id` IN ("."$id_array".")";
    var_dump($gone);

above var verifies that the query is formed correctly, with comma separated id’s

    $goodbye = mysqli_query($dbc, $gone);

    if ($goodbye) { $delete_success = true; var_dump($delete_success);}
    else { $delete_success = false;}
    var_dump($delete_success);

above var dump shows bool false

    //mysqli_close($dbc);
    if($delete_success == true) { echo 'done';
    header('Location: newwriter_profile.php');
  } else
      {
    echo "Error b/c delete failed";

the above echo shows after checking any number of boxes and hitting delete

      }

  }


submit_delete();

mysqli_free_result($goodbye);
mysqli_close($dbc);


?> 

Answer 1

I solved my problem. I realized that during my haphazard development, I had created my database user with associated privileges BEFORE actually creating my uploads table. I ran a grant permission statement on my database user and miraculously I am able to delete using the above code. This also solved another issue I was having involving SESSION variables getting lost between pages.

This was an absolute nightmare – I hope this helps someone else as well. Thanks for your input.