jeremyevans/sequel_postgresql_triggers — pull request #3 by magnetised (2014-02-13 09:27:52+00:00)
Title: The touch trigger should update the timestamp column when it is currently NULL

The `column_name <> CURRENT_TIMESTAMP` behaves unexpectedly when `column_name` is NULL so if your timestamp columns start out as null then the timestamp is never updated by the trigger.

On postgres 9.2.4:

spgt_test=# select NULL <> CURRENT_TIMESTAMP as result;
result
--------

(1 row)