W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > April to June 2006

[#valueTesting] xsd:date

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Wed, 07 Jun 2006 13:51:10 +0100
Message-ID: <4486CBBE.3040301@hp.com>
To: RDF Data Access Working Group <public-rdf-dawg@w3.org>

To make things more interesting, consider xsd:date.  Currently, as defined, a 
SPARQL query processor can't add xsd:date and use "=", "<".  So it can't 
(legally) provide ORDER BY on xsd:dates.  This is surprising.

F&O provides date operations for operators lt, le, gt, ge, eq, ne based on the 
start point of the date duration.

[I can't find a promotion rule for dates to dateTimes so it's not like 
float/double.  xsd:date, xsd:dateTime can't be compared]

In SPARQL, where we use "=" for what is "eq" in XPath expressions (we don't 
have the concept of sequences).

   xsd:date("2004-12-25-12:00") = xsd:date("2004-12-26+12:00")

is false (there are not RDFterm-equal) even though they are same value.

The lack of "<" for ORDER BY is also a potential area for not meeting user 
expectations.

The full list of types from XSD in this category is:

For equals/not-equals and less-than etc:

xsd:date
xsd:time

For equals/not-equals:

xsd:duration
xsd:gYearMonth
xsd:gYear
xsd:gMonthDay
xsd:gDay
xsd:gMonth

	Andy
Received on Wednesday, 7 June 2006 12:51:30 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:26 GMT