[vtiger][Webservice] Database error while performing requested operation

Question

I use the Vtiger webservice with its different methods CRUD, login ... etc. I created a task via the Calendar module, it worked well, but when I want to delete it does not work.

If I'm not mistaken, I need to have the object's id (so Calendar) in order to delete it. So I do:

public static function getTaskUser($user)
{
    $idUser = self::getUserAccountId('XXXX');
    $vtiger = new VtigerWS();
    $connect = $vtiger->getConnection();
    if ($connect && $connect['success'] == true) {
        $response = $vtiger->query("id", "Calendar", "parent_id = '$idUser' ORDER BY id");

        if ($response['success'] == false) {
            $result = $response['error'];
        } else {
            $result = array();
            foreach ($response['result'] as $task) {
                $result[] = $task['id'];
            }
        }
    } else {
        $result = $connect['error'];
    }
    $vtiger->logout();
    return $result;
}

==> In this function, I first look for the user id in vtiger (the user who was assigned to the previously created task). It works well.

But when the query is running:

($ vtiger-> query ("id", "Calendar", "parent_id = '$ idBaz' ORDER BY id");)

I get an error:

"code" => "DATABASE_QUERY_ERROR"
"message" => "Database error while performing requested operation"

The connection is good, I tried a query SELECT * FROM Calendar it does not work either ... I do not see where the error can come from.