- From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
- Date: Thu, 9 Jun 2005 15:31:34 +0100
- To: DAWG public list <public-rdf-dawg@w3.org>
Review of http://www.w3.org/2001/sw/DataAccess/rq23/ v1.379 This is a critical issue. I raised it on IRC when reviewing section 11 as per last weeks action, but neglected to mail the list and so forgot. Apologies. Promotion order is given as: * xs:double * xs:float * xs:decimal with types being promoted to the one obove in the list. However xs:float does not subsume xs:decimal - according to http://www.w3.org/TR/xmlschema-2/#decimal The value space of decimal is the set of numbers that can be obtained by multiplying an integer by a non-positive power of ten and all minimally conforming processors must support decimal numbers with a minimum of 18 decimal digits. This exceeds the precision* of xs:float and xs:double in some cases, so the type "promotion" may well be lossy. * Type Epsilon integer 1.0 float 1.0e-5 double 1.0e-9 decimal 1.0e-17 My recollection is that we agreed to start with double, dateTime and integer (c.f. http://www.w3.org/2001/sw/DataAccess/ftf4.html RESOLVED: to address valueTesting by choosing datetime, date, time; date less-than, date-greater-than, date-equal; string ops per 1.171; numeric double, integer, 9 numeric ops above, per xquery f&o with EricP, KendallC, SteveH abstaining), since then we have aquired xs:decimal, which complicates matters greatly. Suggested replacement text: * xs:double * xs:float * xs:integer And replace all occurances of xs:decimal in the text with xs:integer. Drop note in A / B entry of Table 11.1. N.B. xs:float does not subsume xs:integer either, but the overlap is much bigger, and this kind of conversion is common in programming laguages so will hopefully be less supprising. - Steve
Received on Thursday, 9 June 2005 14:31:52 UTC