I work a lot with Unix times as integers, but would like to store them in Postgres as 'timestamp(0) with time zone' for convenience and readability. Unfortunately the syntax to translate between the two is a little cumbersome, so I'm looking at hiding it away behind a function - or a cast. However, the CREATE CAST docs say that I have to be the owner of either the source or target types, which presumably means I can't define a cast from timestamptz to int.