Undo in web applications is not very popular. Actually, I have used no web app that had extensive undo capabilities. I was reading about this recently somewhere and started thinking if I could make an undo feature for MagnaCRM and how I would go about implementing it. I certainly don’t intend to do it for v1.0 as I already have a full plate.

I think the most difficult operation to undo is a delete, because deleting a record may require deletion of dependant records (e.g. delete an account and you also delete all related contacts). Moreover, instead of deleting from the database you must only flag affected records as deleted. The good thing is that I can offer undo for delete operations easily, since I already have a Recycle Bin feature (deleted records go there and you can undelete them at any time).

Edits seem easier to undo although they could prove to be trickier. You need some kind of auditing mechanism that logs all changes done to records by each user. Then you use that to go back to previous states and you could even offer a redo.

The question that I needed to answer is: should I offer an undo feature that will only undo delete operations or leave it all for next version? I’ll probably do the later, as it will be rather confusing to have an undo button after deleting a record but not after editing it! For v1.0 the Recycle Bin will have to suffice: you can still undelete something even if no convenient undo button is offered.