There is also newId
function, witch returns the next new ID, so you can use it to insert a new row.
$id = $this->getDbTable->newId('table_name', 'id');
$data = array(
'id' => $id,
'data' => $data
);
$this->getDbTable->insertRow('table_name', $data);
Now you can do whatever you want with your $id
.