If select option is unchecked, delete it from Database - Bootstrap Multiselect - php

Question

I have an html table with bootstrap-multiselect in one of the columns. I want the database to delete the role when the checkbox is unchecked.
I am listening to the changes using if (isset($_POST['roles_checkbox'])). Therefore, when the checkbox is unchecked, it never gets called and nothing happens. If the user has 2 roles and 1 gets unchecked it gets deleted. Nevertheless, if the user has 1 role it cannot be deleted. I want the users to be able to have no role assigned to them.
<?php
echo "
<!--User Roles-->
<td>
<form method='post'>
<input type='hidden' name='user_id' value=" . $row["user_id"] . ">"; ?>
<select class='roles_checkbox' multiple='multiple' name="roles_checkbox[]"
onchange='this.form.submit()'>
<?php $a = 1; ?>
<?php foreach ($roles as $data):
$new_sql = "SELECT role_id from users_roles, users WHERE users_roles.user_id = '" .
$row["user_id"] . "' AND users_roles.role_id = '" . $a . "' GROUP BY
users_roles.user_id";
$checked_or_not = mysqli_query($connect, $new_sql);?>
<option value="<?php echo $a ?>" <?php if ($checked_or_not->num_rows != 0) echo
"selected=\"selected\""; ?>><?php echo $data ?></option>
<?php $a++; ?>
<?php endforeach; ?>
</select>
<?php
echo "
</form>
</td>";
<!--Update User Role listenning to select box-->
if (isset($_POST['roles_checkbox'])) { // Use select name
$user_id = $_POST['user_id']; // Use input name to get user id being modify
// Start by deleting all the roles
for ($i = 0; $i < $count; $i++) {
$a = $i + 1;
// Deleted all roles
$query2 = "DELETE FROM users_roles WHERE user_id = '$user_id' AND role_id = '$a'";
_log('$query2: ' . $query2);
$in_ch2 = mysqli_query($connect, $query2);
}
foreach ($_POST['roles_checkbox'] as $selectedOption) {
//echo $selectedOption . "\n";
// Insert selected roles
$query = "INSERT INTO users_roles(user_id, role_id) VALUES ('$user_id', '" . $selectedOption . "')";
$in_ch = mysqli_query($connect, $query);
}
echo "<meta http-equiv='refresh' content='0'>";
$connect->close();
}
?>

Answer 1

I think you're on the right path with your attempt at deleting all current user roles before reinserting the new ones. However, I think this is also where the issue lies.
Try instead of this:
// Start by deleting all the roles
for ($i = 0; $i < $count; $i++) {
$a = $i + 1;
// Deleted all roles
$query2 = "DELETE FROM users_roles WHERE user_id = '$user_id' AND role_id = '$a'";
_log('$query2: ' . $query2);
$in_ch2 = mysqli_query($connect, $query2);
}
Doing this:
$delete_query = "DELETE FROM users_roles WHERE user_id = '$user_id'";
mysqli_query($connect, $delete_query);
EDIT based on comments
Knowing that user can have no roles, you would start be removing your initial input check if ($_POST['roles_checkbox']) and reqlacing it for a user id check i.e. if ($_POST['user_id']) this allows you to continue running the rest of your process without relying on roles input. See my updated example below...
// First check if the request includes a user id
$user_id = !empty($_POST['user_id']) ? (int)$_POST['user_id'] : null;
if ($user_id) {
// Second, lets delete all existing roles
$delete_query = "DELETE FROM users_roles WHERE user_id = '$user_id'";
mysqli_query($connect, $delete_query);
// Now we check if the request includes any selected role
if (!empty($_POST['roles_checkbox'])) {
// This array will hold MySQL insert values
$insert_values = [];
// Loop through request values, sanitizing and validating before add to our query
foreach ($_POST['roles_checkbox'] as $role_id) {
if ($role_id = (int)$role_id) {
$insert_values[] = "('{$user_id}', '{$role_id}')";
}
}
// Double check we have insert values before running query
if (!empty($insert_values)) {
$insert = "INSERT INTO users_roles(user_id, role_id) VALUES " . implode( ', ', $insert_values );
mysqli_query($connect, $insert);
}
}
echo '<meta http-equiv="refresh" content="0">';
$connect->close();
}