Re: Inserting Calendar.Time in a database

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Thu, 5 Aug 2004 21:19:07 +0000 (UTC), Martin Dowie wrote:

> Dmitry A. Kazakov wrote:
>>> I need to insert some timestamps (type Ada.Calendar.Time) in a
>>> database accessed via ODBC using gnade+gnat 3.15p.
>>>
>>> I've looked for timestamp support in the gnade sources without much
>>> luck, I've specially checked the embedded sql support and I haven't
>>> found nothing for this purpose.
>>>
>>> I'm completely clueless about the ODBC client packages so if someone
>>> has done this before (with gesql or directly), a quick pointer for
>>> the things to look at would be great.
>>
>> The problem is that Ada.Calendar.Time is a political time, while
>> persistent time stamps should be UTC or any other absolute time. I
>> know no OS-independent solution for that.

Then quite often one need to pass time stamps across partitions distributed
over different time zones. Presently it is very painful.

> Ada.Calendar.Time_Zones might be of use to you. You could store
> the value as a string (Ada.Calendar.Formatting).
>
> See http://www.martin.dowie.btinternet.co.uk/

I see a problem with it. UTC_Time_Offset is not constant, so there also
should be an atomic way to get exact UTC. Actually Ada.Real_Time.Time seems
a better candidate for UTC. I would add it there. Then why not to provide a
numeric type to be a FILETIME equivalent (64-bit value representing the
number of 100-nanosecond intervals since January 1, 1601)? Alternatively
one could define a full-blown UTC_Time type synchronized with
Ada.Real_Time.Time.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de