A user is executing a transaction in an Oracle database. Which of the following choices correctly identifies all the statements that will generate undo information within the transaction? A . insert statements only B . update and insert statements only C . delete statements only D*. delete and update statements only E . delete, insert, and update statements only could not understand why choice D is correct, I remember that insert also put some information (such as ROWID) into undo segament, otherwise how oracle could rollback? could anyone kindly explain? thanks
Beksy Kurian
Ranch Hand
Joined: Jul 11, 2001
Posts: 254
posted
0
I would say 'least undo' for insert rather than saying no undo at all. when we rollback: delete requires reinserting the row(reconstruct the actual row) insert requires just to delete the row (takes less bytes to store a rowid). Hummm! If the question was not 'least undo', I would have given the answer 'E' and gotten a score 0.
0
