Andrew,

I did not mean asking for undo from a life-time log. Since FlashBack Technology is already there, I just mean that world's most advanced database (PostgreSQL, as they say), must have an optimized way for undoing of at least a week changes. A week log is enough and PostgreSQL can keep on removing old logs automatically.

Secondly, it must be left to the user to decide for the number of days of archive he want to store. Again upto a week max.

RPK wrote:

Why the heck can't you create a reversing transaction? That's what ordinary mortals do. Demanding unlimited undo at some time that is arbitrarilly distant in the future strikes me as wholly unreasonable.

What do you mean by "accidental update"? What you really appear to mean is that a program or a human operator has made an error, and incorrectly told the database to commit a transaction. The answer surely is to correct the behaviour of the program or human, rather than wanting the database to provide an undo facility. Alternatively, this should be handled at the application layer, using something like table_log.

Some things just don't work well with this sort of facility. Just ask your bookie if you can undo a bet that you "accidentally" placed with him and which, three days later, you discover (after the race) was a mistake.

cheers

andrew