Detecting column changes in a postgres update trigger

Question

I have a postgres database with several tables that I want to watch for updates on, and if there\'s any updates, I want to fire a \"hey, something changed\" update. This wor

Answer 1

Read up on the hstore extension. In particular you can create a hstore from a row, which means you can do something like:

changes := hstore(NEW) - hstore(OLD);
...pg_notify(... changes::text ...)

That's slightly more information than you wanted (includes new values). You can use akeys(changed) if you just want the keys.