[SOLVED] Deleting using checkboxes

[supanoob]

Ok, so im wanting to delete multiple things from a database using checkboxes, now i know how to use checkboxes in php etc. my question is would this be done using a basic while loop? i mean would i query all the things and then do

 

while ($check_box == 'ON')

{

do the delete script

}

 

or is there something more to it?

[Wuhtzu]

There is quite a few approaches which will lead to the functionality you want. All of them have to end up with one of the two following "SQL queries":

 

Query the database once:

"DELETE FROM table WHERE id=$id_to_delete_1 AND id=$id_delete_2 AND id=$id_delete_3"

 

Query the database multiple times:

foreach($ids_to_delete as $id_to_delete) {
    mysql_query("DELETE FROM table WHERE id=$id_to_delete");
}

 

How you get to one of those final "statements" may depend on the given project / situation but it will be something like:

 

<!-- This form is of course created by looping through some database results -->
<!-- The <input>-fields are named as an array which will result in $_POST['ids_to_delete'] being an array holding all the ID's we want to delete -->
<form action="" method="post">
  Post 5 <input type="checkbox" name="ids_to_delete[]" value="5">
  Post 6 <input type="checkbox" name="ids_to_delete[]" value="6">
  Post 19  <input type="checkbox" name="ids_to_delete[]" value="19">
  Post 31  <input type="checkbox" name="ids_to_delete[]" value="31">
</form>

<?php
$ids_to_delete = $_POST['ids_to_delete'];

//Run the delete-query for each entry in the $ids_to_delete array
foreach($ids_to_delete as $id_to_delete) {
  $result = mysql_query("DELETE FROM table WHERE id=$id_to_delete");
  
  if($result) {
    echo "Post $id_to_delete was successfully deleted";
  }
  else {
    echo "Post $id_to_delete was not deleted";
  }

}

?>

 

I don't have any really good reason for using multiple queries instead of one or the other way round. I guess there is no doubt that the single query method is fastest, but since you wont be deleting 1000 posts I wont be concerned about speed / performance. Personally I would stick with the multiple query method since it allows you to track the progress / status of each deletion very easily and you do not have to make some ugly code to brew up the "WHERE id=5 AND id=6 AND id=19 and ID=31"

[supanoob]

Thanks best reply to a post ive made, very detailed.

[sasa]

Query the database once:

"DELETE FROM table WHERE id=$id_to_delete_1 AND id=$id_delete_2 AND id=$id_delete_3"

SQL must be

"DELETE FROM table WHERE id=$id_to_delete_1 OR id=$id_delete_2 OR id=$id_delete_3"

[Wuhtzu]

Thanks sasa, my mistake

[Barand]

I prefer the more efficient single query approach.

 

Give each c/box a value of the record id.

 

<?php
if (isset($_GET['del_id']))
{
    $del_id_list = join (',', $_GET['del_id']);
    
    $sql = "DELETE FROM tablename WHERE id IN ($del_id_list)";
    
    echo $sql;             // execute delete query here
}

?>
<form>
item 1 <input type="checkbox" name="del_id[]" value="1" /> <br />
item 2 <input type="checkbox" name="del_id[]" value="2" /> <br />
item 3 <input type="checkbox" name="del_id[]" value="3" /> <br />
item 4 <input type="checkbox" name="del_id[]" value="4" /> <br />
item 5 <input type="checkbox" name="del_id[]" value="5" /> <br />
item 6 <input type="checkbox" name="del_id[]" value="6" /> <br />
<input type="submit" name="sub" value="Delete selected">
</form>