Automagically log changes in table

[George Sakkis]

This is more in the context of Turbogears/SQLAlchemy, but if anyone
has implemented something similar with other packages it might be
useful to know.

I'd like to have a way to make a table "loggable", meaning it would
get, say, two fields "last_modified" and "modified_by", and every
write operation on it would automatically record the time and the id
of the user who did the addition or change (I'm not sure how to deal
with deletions let's leave this for now). Has anyone done something
like that or knows where to start from ?

George