Re: Timestamp weirdness

On 7/25/05, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> [...]
> The difficulty with both 2 and 3 is that the driver has no very good way
> of knowing whether it's writing to a timestamp with tz or one without.
> We can know the parameter datatype we send, but if that gets converted
> to the other type within the server, you're going to get burnt.

If I TIMESTAMP WITH TIME ZONE is implemented on the server as a
(timestamp, time zone)-pair, the server should be able to cast
TIMESTAMP WITH TIME ZONE correctly to TIMESTAMP WITHOUT TIME ZONE as
described in the SQL standard:

From TIMESTAMP WITH TIME ZONE to TIMESTAMP WITHOUT TIME ZONE
 TargetValue = SourceValue.UTC + SourceValue.TimeZone

This cast is something like a conversion from a instance in time to a
local time representation.

In this case I would propose to send (if possible) timestamp and time
zone to the server, no matter if we'll write a TIMESTAMP WITH TIME
ZONE or a TIMESTAMP WITHOUT TIME ZONE value. We could have some hope
to get correct results then.

Regards,
Alex