- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Wed, 07 Jun 2006 13:51:10 +0100
- 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 UTC