http://www.w3.org/Bugs/Public/show_bug.cgi?id=5023 Michael Kay <mike@saxonica.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |mike@saxonica.com --- Comment #9 from Michael Kay <mike@saxonica.com> 2009-04-14 23:05:13 --- If we're advising users which of these mechanisms to use under which circumstances, then I think there are two observations I would want to make: (a) it's a lot easier for an implementation to enforce identity constraints and CTA while processing the document in a streaming manner than it is to enforce assertions (b) using a specialized mechanism such as identity constraints rather than a general mechanism like assertions may result in a more focused and intelligible error message when the condition is violated. For example, the assertion test="count(//empno)=count(distinct-values(//empno))" is unlikely, if violated, to result in an error message that tells the user how many duplicate employee numbers there are, which numbers are duplicated, or where to look for them in the instance document. I think the same is probably true of other reasonable ways of expressing this constraint, such as test="every $a in //empno, $b in //empno satisfies $a is $b or $a ne $b" -- Configure bugmail: http://www.w3.org/Bugs/Public/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the QA contact for the bug.Received on Tuesday, 14 April 2009 23:05:22 GMT
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