Derick Rethans wrote:
( Slipping a date through DateTime and returning it DATE_W3C seems to be
adding the correct daylight saving details so far and allowing ADOdb date to
work )
This is not the correct thing to do, as you will lose timezone
information. The W3C format only stores UTC offsets (in the form of
+00:00). However, that same UTC offset can be used in different areas
with different DST changes. Best thing is to store in Unix timestamps.
OK - I think I understand what is 'missing' now!
The only thing ever stored in the database *IS* Unix timestamps. Doing
anything other than that is unmanageable, yet some frameworks use
'server based' times in their systems, simply because they do not bother
with daylight saving and only 'serve' one timezone!
The second you have to manage 'real' time across timezones then daylight
saving becomes essential, BUT only on the display side! Since the
browser only provides a time offset, this is useless and to be honest
should simply be ignored ( until it is upgraded to provide the correct
information ;) ). So we need a 'display' function that takes a simple
numeric epoch, and a separate timezone id into which the epoch is to be
'converted'. My W3C mapping works simply because ADOdb then converts
that to it's own simple offset abbreviation - in my case GMT or BST. As
long as DateTime passes the full 64 bit number the date range from 100AD
is also preserved ( and further back if 2 digit years are disabled ). If
I want to display the 'real' timezone with this 'time' then I just add
it in place of ADOdb's 'timezone'. I am tempted to simply adjust the
ADOdb class to take a timezone in place of the simple GMT switch it
currently uses.
The return path is just the reverse and simply needs to take the client
display offset off prior to storage of the UTC epoch. SO we use
DateTimeZone to get an offset value for the clients timezone and simply
add or subtract this from a timezone agnostic display on the client end
when entering new times.
( I've posted this simply as an aid - it may help someone )
--
Lester Caine - G8HFL
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