[DB-SIG] Behaviour of .commit()/.rollback() when autocommit=True

[Gerhard Häring]

Several database modules seem to have a sort of unofficial extension - 
the autocommit mode, without transaction handling. I'd like to hear your 
opinion on what .commit()/.rollback() should do in this case.

Option 1)

Behaviour: .commit() dies nothing, .rollback() raises an exception

Rationale: this makes it easier to program applications that work in 
both autocommit mode and transactional mode, depending on the 
configuration or DB-API module used.


Option 2)

Behaviour: .commit() and .rollback() both raise an exception
Rationale: There is nothing to commit or roll back, so these calls don't 
make any sense and the user should be alerted of this fact.


Option 3)

Behaviour: .commit() and .rollback() both do nothing.

Rationale: (Almost) same as #1?


Do you have any other suggestions? Which would you prefer?

-- Gerhard