date type conversions

===================================================================
This message has been sent to a DEAD mailing list, and subsequently
reforwarded to the proper one: pgsql-general@postgresql.org
===================================================================


How can I tell if an automatic type conversion will be done on
a particular field?  For example, given a datetime field d, why
does psql accept set d = 'now()' but require set d = datetime(now())
without the ''s?  Datetime's seem to work through ODBC to Access
where timestamps turn into text...

  Les Mikesell
   les@mcs.com