When an application and/or process has completed operations with the database, it must release resources by closing the open files and disconnecting from the database engine.
Below is the code for Done():
//
// Done()
//
// This function handles the housekeeping of closing, freeing,
// disconnecting and logging out of the database
//
function Done ($ses) {
echo "<h4>DONE</h4>\n";
// logout
$ses = null;
}