I get an LDAP feed in for my employee database - basically a big csv file. This updates once a night and I revise all of our internal apps based on this spreadsheet.
When a new person comes on the feed I have a trigger in my table that fires and spits out a "created" field so that I can run queries based on when the employee row entered our system.
My question is, is there a way to trigger when nothing is queried? I would like to date (time) stamp a user row based on that row no longer being on the feed. But also I don't want that overwritten every night since I would like my "left_date" field to be accurate.