illuminate/database — pull request #101 by bencorlett (2013-01-06 23:30:23+00:00)
Title: Fixing inconsistency with asDateTime()

All other fields in Eloquent will return NULL if they're not set, however asDateTime() returns a timestamp - http://d.pr/i/r6pm

I have fixed so a value is only returned as a timestamp if the field is actually set.