- 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