RE: [XQuery] IBM-XQ-025: Comparable types in Order By clause

I personally think that "order by" is one of those things that should
never fail. If two items have non-comparable types, then their relative
ordering in the result should be implementation-dependent, and no error
should be raised. XML deals with semi-structured data, and it's common
to find elements that allow, for example, the union of an xs:integer or
the string "N/A". I don't see why we should make it impossible to sort
on such fields.
 
Having said that, the proposed change is an improvement.
 
Michael Kay

-----Original Message-----
From: public-qt-comments-request@w3.org
[mailto:public-qt-comments-request@w3.org] On Behalf Of Don Chamberlin
Sent: 17 February 2004 04:45
To: public-qt-comments@w3.org
Subject: [XQuery] IBM-XQ-025: Comparable types in Order By clause



(IBM-XQ-025) Section 3.9.3, Order By and Return Clauses: The first
bulleted list says that each orderspec in an Order By clause must
"return values of the same type for all tuples." We should use a
different term: "comparable types" rather than "same type", and we
should define the term. For the purposes of this rule, all numeric types
should be "comparable". The types xs:string and xdt:untypedAtomic should
be "comparable". Any atomic type should be "comparable" with its derived
types, and two atomic types that are derived from the same base type (or
that are both derived from numeric types) should be "comparable". 

--Don Chamberlin