> The window I'm thinking about offering will have child windows, where they can alter records that have several unique varchar columns. They might alter a varchar column that will cause a colision. Not a problem, the app will warn them of the conflict and ask if they wish to proceed. They can repeat this on other rows and do a lot of updates inserts and deletes. And when they are finished they might decide they don't like the results of what they've done and hit "Cancel".
>
> If I start and commit transactions each time the user updates the database, I wont be able to roll them back if the user changes their mind, and hits "Cancel" when quitting the parent window of this activity.

I see the point. In this case I would just make a kind of timer which
warn user after some big enough time of inactivity (say, one hour) and
if the user hasn't responded - cancel the work.
And as a boss, I would consider a punishment for this user.
Administrative sanctions are proven to be more effective.

SY, SD.