- From: Ashok Malhotra <ashokma@microsoft.com>
- Date: Wed, 9 May 2001 05:20:20 -0700
- To: "Jeff Rafter" <jeffrafter@definedweb.com>
- Cc: <xmlschema-dev@w3.org>
No, you cannot in general assume that 1999-01-16 = 1999-01-16T00:00:00Z You may chose to interpret dates without timezones as belonging to a particular timezone, often the local or default timezone, in your application but that's specific to your usage. All the best, Ashok =========================================================== Ashok Malhotra <mailto: ashokma@microsoft.com> Microsoft Corporation 212 Hessian Hills Road Croton-On-Hudson, NY 10520 USA Redmond: 425-703-9462 New York: 914-271-6477 -----Original Message----- From: Jeff Rafter [mailto:jeffrafter@definedweb.com] Sent: Tuesday, May 08, 2001 8:14 PM To: Ashok Malhotra Cc: xmlschema-dev@w3.org Subject: Re: Time Zones and XML Schema date types >Consider a date like May 8, 2001. This is actually a period of 24 hours >(roughly). The exact time the period starts and ends depends on the >time zone. So, I think, its clear why such types need a timezone. Understanding both types as periods of time certainly does help, thanks. >What is more controversial is why we allow dates without a timezone. >This is to conform with SQL and also common usage. Yes, it makes >comparing dates with and without time zones complicated. Is this a case where the common usage should outweigh other concerns, especially when common usage includes an international standard? It seems as though XML Schema could have avoided adding to the ISO spec in this gray area by simply allowing implementations to assume GMT-- though I am even a little fuzzy with how I think this would work. Essentially, isn't it safe to presume (although the XML Schema spec prohibits it): 1999-01-16 = 1999-01-16T00:00:00Z Assuming that 1999-01-16 is the 16th of January 1999-- shouldn't it follow that the starting instant of the date *is* 00:00:00Z? I suppose not, I am faltering back and forth between a day is 24 hours (roguhly) beginning in timezone X and a day begins when the international date line is crossed. I am sure all of this has been thought through already (probably for many years now). Thanks again, Jeff Rafter Defined Systems http://www.defined.net XML Development and Developer Web Hosting
Received on Wednesday, 9 May 2001 11:11:28 UTC