2009/3/25 Thomas Dalton thomas.dalton@gmail.com:
An extra column in any table with a "user id" column for "original user id" (which would be identical to user id for the vast majority of rows) would be sufficient for most unmerges. There would still be a problem if an account was involved in more than one merge, though.
I can see such being the case, e.g. prolific sockpuppeting vandals. However, preserving the "original UID" in all merges would likely suffice - I mean, a complete unmerging would be OK in all cases I can think of.
- d.