Don't assume that the epoch starts at 00:00:00, January 1, 1970,
because that is OS- and implementation-specific. It is better to
store a date in an unambiguous representation. The ISO 8601 standard
-defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
+defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH:MM:SS
(that's a literal "T" separating the date from the time).
Please do use the ISO 8601 instead of making us guess what
date 02/03/04 might be. ISO 8601 even sorts nicely as-is.