- From: McMahon. Brendan (IT Solutions) <Brendan.McMahon@mail.esb.ie>
- Date: Mon, 25 Nov 2002 18:44:48 -0700
- To: W3C XML Schema Comments list <www-xml-schema-comments@w3.org>
Hi, I am currently working using XML Schema to define maximally rigorous market message schemas for the electricity market in Ireland. In the course of this work, we regularly need to represent specific time periods (i.e. a specific duration in time occurring at a specific date/time) as atomic data items. The ISO8601 standard from which XML Schema derives its datatypes does document a standard representation for "specific time period" using the start date/time, followed by a "/" as a time period indicator, followed by either an (exclusive) end date/time OR a time-period. e.g. 2002-11-20T12:45:00.000/2002-11-20T13:00:00.000 or 2002-11-20T12:45:00.000/PT15M represent the 15 minute time period beginning at 12:45pm on the specified date. Although XML Schema 1.0 includes "dateTime" and "duration" built-in data-types, there is no way of expressing a specific time period as a single element/attribute. I would like to suggest that a "dateTimePeriod" datatype be added to the built-in datatypes, with the obvious specification constraints that: the starting (and ending, if specified) date/time parts be valid according to normal "dateTime" rules in the first form, the ending dateTime must not be less than the starting dateTime in the second form, the duration part must be valid according to normal "duration" data-type rules It is debatable whether it should be possible to omit the second part, indicating a specific time period (as distinct from an instant in time) whose duration is either defaulted in the context, or specified elsewhere (e.g. a standalone "duration" elsewhere in the schema). More generally, we would also like to see more extensive data validity specification capabilities added to XML Schema (e.g. the best of Schematron, Relax NG, etc., including the ability to specify more user friendly validation error message texts. Keep up the good work Regards, Brendan McMahon ESB * ** *** ** * ** *** ** * ** *** ** * This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. Any views or opinions presented are solely those of the author, and do not necessarily represent those of ESB. If you have received this email in error please notify the sender. Although ESB scans e-mail and attachments for viruses, it does not guarantee that either are virus-free and accepts no liability for any damage sustained as a result of viruses. * ** *** ** * ** *** ** * ** *** ** *
Received on Monday, 25 November 2002 20:46:05 UTC