Re: Time zones calculation - browser apps

From: joel garry <>
Date: Wed, 27 May 2009 08:51:20 -0700 (PDT)
Message-ID: <>

On May 27, 8:27 am, Jeremy <> wrote:
> Hi,
> this question pertains to +
> Say we have a database which runs on a server which is ALWAYS set to
> GMT.
> We have users of a web application in two timezones - say today this is
> GMT+1 and GMT+2. In the winter, these will be GMT and GMT+1.
> The application is browser based (so not concept of client time) but we
> would like it to be able to present times (from database columns of type
> DATE) with an appropriate offset so that the user sees them presented
> corectly (for them). The database stores all dates using db server time.
> This statement:
> select tz_offset('cet') from dual;
>  = gives us +2
> select tz_offset('wet') from dual;
>  = gives us +1
> When the clocks go back in the autumn, will these values automatically
> alter to +1 and +0 ?
> Sorry of this is not too clear - I understand what I am asking :)
> --
> jeremy

Poke around on meatlink with searches like for timezone patch. Note: 553812.1 is pretty informative. I didn't totally understand it until I saw strangeness in EM job times, or something, I was using the wrong java. Dates of DST change far more often than they should, too.

Basically, you have to be sure java, your OS, and Oracle are all synchronized and up to date on timezone patches. It also depends on exactly what features of date and time you are using, and which countries your timezones are dealing with. Not to mention your client OS settings, especially if they dual-boot between significantly different OS's, though that tends not to be an Oracle problem. I still crack up watching the date/times in ms outlook email chains across timezones, and even some blog threads. I'm easily entertained.


-- is bogus.
Received on Wed May 27 2009 - 10:51:20 CDT

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