CI new record after successful return value judgment, is the use of isset or empty

Q:

Add a return $this->db->insert_id () after the new record has been inserted successfully;

$digg _id = $this->m_feed_digg->create (Json_decode ($data));
if (Isset ($digg _id)) {
New success, return to likes entity information
////
}else{
Echo ' ERROR ';
}

This condition is isset ($digg _id) good or empty ($digg _id)

A:

The empty function should be used, because the returned id,id should be >=1, and the insertion failure would return 0

Empty when judging 0, will be judged null, get True

Isset judge 0, will be judged as non-null, get False

CI new record after successful return value judgment, is the use of isset or empty