Manually update a "Last modified" field

[benomite]

Is there a way to update manually a "Last modified by" or "Last modified time" field?

We use a field to check who was the last person to update an ID field. But we sometime have to bulk update these fields for cleaning or managing the database and the "last modified by" is now entirely set to the creator/admin who made the update.
- Is there a way to update manually these fields?
- Is there an existing extension for this? or a script ?
- Maybe there is a way to "impersonate" a user in order to set the needed values to those fields? (I tried this with the interface functionnality to see interface as another user, it did not work)

Thank you very much !

[kuovonne · Accepted solution]

Nope. You cannot manually set the last modified time or last modified by. 

You can create “override” fields for the time and person, and then use formula fields to show either the actual last modified time/by or the result of the override field, depending on the last modified time of both the original field and the override field. 

However, this method requires maintaining several fields and I have a hard time picturing it actually being worthwhile to implement. 

If you need to know the last modified info only occasionally, the info is in the record history (at least as long as the record history exists). If you are using the last modified info to record who and when something happened, you may be better off having editable fields to store that info and filling the editable fields with an automation.