private function associateGroup(Connection $conn, $subjectId, $groupName)
{
$stmt = $conn->prepare('SELECT subject_id FROM sgroup_subject WHERE subject_id = ? AND sgroup = ?');
$stmt->execute([$subjectId, $groupName]);
if (!$stmt->fetchColumn()) {
$this->insertUpdate($conn, 'sgroup_subject', ['subject_id' => $subjectId, 'sgroup' => $groupName]);
}
}