[DUG] Timezones for Bills and things

Fri Nov 25 12:57:47 NZDT 2016

Yep, so some devices are showing daylight savings time and others are not
for the same physical file, proving the file is stored in UTC and being
displayed in local time.

From: delphi-bounces at listserver.123.net.nz
[mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Rohit Gupta
Sent: Friday, 25 November 2016 10:48 a.m.
To: NZ Borland Developers Group - Delphi List
Subject: Re: [DUG] Timezones for Bills and things

Not quite.  Because I am not referring to the actual timestamp that it is
showing me.  But the fact that between the 5pcs, a laptop and surface and
usb harddisk.  The timestamps are different twice a year.  If it was storing
them as utc then they would all be always in sync with each other.  They
would all change by the same hour and look the same in beyond compare.  But
different files change their timestamps on different pcs.  If its storing
them as utc then it is selective about it.  Which is worse than not saving
them as utc.  

Rohit

On 25/11/2016 10:06, David Brennan wrote:

Hi,

Surely that is evidence that Windows is storing timestamps in UTC? If it
wasn’t then a file stamped as 3pm would always say 3pm no matter what
timezone you changed your computer to.

Regards,

David.

From: delphi-bounces at listserver.123.net.nz
[mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Rohit Gupta
Sent: Friday, 25 November 2016 9:59 a.m.
To: NZ Borland Developers Group - Delphi List
<mailto:delphi at listserver.123.net.nz> <delphi at listserver.123.net.nz>
Subject: Re: [DUG] Timezones for Bills and things

Thanks Ross,

however I would dispute that windows stores file timestamps in utc.  Because
twice a year there is mayhem as only some files change their timestamp by an
hour.  And these files are different on different workstations.

Maybe it's true for the server version of windows.

Rohit

On 24/11/2016 17:39, Ross Levis wrote:

I suggest store in UTC, like Windows does for file timestamps, and use
Windows functions like GetTimeZoneInformation and
SystemTimeToTzSpecificLocalTime to convert to locale time for
display/printing purposes.  A timezone database shouldn’t be required.

From: delphi-bounces at listserver.123.net.nz
[mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Stefan Mueller
Sent: Thursday, 24 November 2016 5:21 p.m.
To: 'NZ Borland Developers Group - Delphi List'
Subject: Re: [DUG] Timezones for Bills and things

https://github.com/pavkam/tzdb has such a timezone database (2014 data).
Using that library makes it easy to convert between timezones.

I think http://www.iana.org/time-zones hosts the latest up to date time zone
data that this tzdb database is based on in case you want to update it to
the latest 2016 data. 

Or you could rewrite your application to use Oracle Database 
 they do have
a timestamp datatype for your table columns so when you select/insert/update
a table all you need to do is to set the correct locale and the database
will do the conversion for you.

https://docs.oracle.com/database/121/NLSPG/ch4datetime.htm#NLSPG263

Kind regards,

Stefan Müller,
R&D Manager

ORCL Toolbox Ltd. 
Auckland, New Zealand 

P Please consider the environment before printing this email

This message is intended for the adresse named above and may contain
privileged or confidential information.
If you are not the intended recipient of this message you must not use,
copy, distribute or disclose it to anyone.

From: delphi-bounces at listserver.123.net.nz
[mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Rohit Gupta
Sent: Thursday, 24 November 2016 4:19 p.m.
To: NZ Borland Developers Group - Delphi List
Subject: [DUG] Timezones for Bills and things

We finally have to deal with time zones.  We use the server date-time
everywhere, rather than relying on workstation date-times.  This is not an
interactive forum type application where the flow of data is merged from
various timezones.  It is a business management system with appointments and
bills etc.  The timestamps of these records have to remain as created.  But
they can not come from the workstation clock.

Going forward, a database server could be servicing workstations in
different time zones.

I am considering

1.	Set the server time as UTC
2.	Keep a table for time zone versus branch (how do I keep this upto
date at daylight saving boundaries)
3.	Use the utc + timezone difference to stamp each bill or appointment
made for each branch.

How is everyone else handling it ?

Regards

Rohit

_______________________________________________
NZ Borland Developers Group - Delphi mailing list
Post: delphi at listserver.123.net.nz
Admin: http://delphi.org.nz/mailman/listinfo/delphi
Unsubscribe: send an email to delphi-request at listserver.123.net.nz with
Subject: unsubscribe

-- 

Regards

Rohit Gupta
B.E. Elec., M.E., Mem IEEE, Mem IET
Technical Director
Computer Fanatics Ltd

Tel 4892280 
Fax 4892290 
Web www.cfl.co.nz

  _____  

This email and any attachments contain information, which is confidential
and may be subject to legal privilege and copyright. If you are not the
intended recipient, you must not use, distribute or copy this email or
attachments. If you have received this in error, please notify us
immediately by return email and then delete this email and any attachments.

_______________________________________________
NZ Borland Developers Group - Delphi mailing list
Post: delphi at listserver.123.net.nz
Admin: http://delphi.org.nz/mailman/listinfo/delphi
Unsubscribe: send an email to delphi-request at listserver.123.net.nz with
Subject: unsubscribe

-- 

Regards

Rohit Gupta
B.E. Elec., M.E., Mem IEEE, Mem IET
Technical Director
Computer Fanatics Ltd

Tel 4892280 
Fax 4892290 
Web www.cfl.co.nz

  _____  

This email and any attachments contain information, which is confidential
and may be subject to legal privilege and copyright. If you are not the
intended recipient, you must not use, distribute or copy this email or
attachments. If you have received this in error, please notify us
immediately by return email and then delete this email and any attachments.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://listserver.123.net.nz/pipermail/delphi/attachments/20161125/9b678464/attachment.html 