Question

I have a table memberships.

I supply my user with a text box, in which there is a list of the current emails in memberships. They can edit the list. Once they send the list back, I want to update memberships so it only contain emails that are in the list the user supplied.

The best way I can think of is just to delete all emails and just insert the whole list back in. Is there a better method?

What I am doing now:

  $mysql->query('DELETE FROM memberships');

  $userEmails = explode('\n', $_POST['users']);
  foreach ($userEmails as $email)
    $mysql->query('INSERT INTO memberships (email) VALUES (?)', $email);

Answer 1

Something like this maybe are what you are looking for (untested). Dont forget to escape your input before using in querys to prevent sql injections.

$userEmails = explode("\n", mysql_real_escape_string($_POST['users']));
$mysql->query("DELETE FROM `memberships` WHERE `email` NOT IN ('".implode("','", array_values($userEmails))."');");
$mysql->query("REPLACE INTO `memberships` (`email`) VALUES ('".implode("'),('", array_values($userEmails)).");");