Re: [xml] Question about error reporting when using key / keyref constraints in Schema

On Thu, Aug 11, 2005 at 03:31:50PM +0200, Kasimier Buchcik wrote:
This is expected, but I understand that it does not help chasing
instance errors.
We changed the behaviour due to streaming validation. Keyrefs
can be only examined when we have traversed all content of the element
for which the keyref was defined (ELEMENTS in this case). I.e. we
need a complete list of all existing key/unique values in the
content to be able to say if a keyref has a correspondent.
Since, for streaming validation, this would mean saving all target
node informations - to be able to report the exact error prone node -
until we are finished with the content, we would loose the profit of
streaming validations: memory. Now, we could save the node
information in the case where we don't use streaming validation,
but this would result in different results for streaming/node-tree
validation. I dunno if such an inconsistency is appropriate,
so feedback from the list is mostly welcome.

  maybe the line of the reference can be saved at the same time of the
value, that's what I did for ID in DTD validation when streaming. And
it is sufficient for the error report you don't need to keep a pointer
to the node.

By the way, I tested this with Xerces-J 2.7.1:

keyref.xml:7,12: (Error) Key 'keyref' with value 'test' not found for
identity constraint of element 'ELEMENTS'.
(the line number points to the end tag of ELEMENTS by the way) 

Xerces uses the same mechanism as we do.

  We can certainly improve over xerces user-friendlyness ;-)


Daniel Veillard      | Red Hat Desktop team
veillard redhat com  | libxml GNOME XML XSLT toolkit | Rpmfind RPM search engine

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