First: entry of First attempt/occurrences.only
Last: entry of Last attempt/occurrences. only
first and last: only first and last attempt/occurrences. entires
each: all attempts/occurrences by specified users
Access Logging options are documented in the SQL Reference: SQL Data Definition Language (Syntax & Examples) manual.
First - inserts a row the first time the indicated permissions are checked for a session (optionally, only if denied)
Each - inserts a new row every time
Last - must do "update if matching log row exists else insert" (because there is no way to know in advance which request will be last)