OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help



   Re: [xml-dev] Creating a XML Schema for an existing database

[ Lists Home | Date Index | Thread Index ]

Jeff Rafter <lists@jeffrafter.com> writes:

> xs:integer is a derived type from the primitive xs:decimal which
> according to the above should be considered derived from
> anySimpleType. (I know you know all this, I am just putting it here
> for completeness) Hence the simple ur-type and xs:integer should be
> comparable but none of the three implementations tested allow it. So,
> should it not be considered a bug?

You missed the impact of my second quote [2]:

 "The mapping from lexical space to value space is unspecified for
  items whose type definition is the *simple ur-type
  definition*. Accordingly this specification does not constrain
  processors' behaviour in areas where this mapping is implicated, for
  example checking such items against enumerations, constructing
  default attributes or elements whose declared type definition is the
  *simple ur-type definition*, checking identity constraints involving
  such items."

XSV (and I presume Xerces) take advantage of this by saying that when
mapping a lexical form to a value for anySimpleType, they always map
to a member of the value space of xs:string.  And xs:string values and
xs:integer values are incomparable.

A processor _could_ choose to dispatch on lexical form and convert
e.g. (anySimpleType)"3.0" to the appropriate member of the xs:decimal
value space, but I'm not aware of any processor which does.


[2] http://www.w3.org/TR/xmlschema-1/#Simple_Type_Definition
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
    2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
            Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk
                   URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]


News | XML in Industry | Calendar | XML Registry
Marketplace | Resources | MyXML.org | Sponsors | Privacy Statement

Copyright 2001 XML.org. This site is hosted by OASIS