NEW ISSUE: Use of Schematron in SCA Specifications

RAISER:  Mike Edwards, on behalf
of the SCA BPEL TC

TARGET: All Specifications which define
XML structures via XSD

DESCRIPTION:

An issue was raised in the BPEL TC which
proposes the use of Schematron for expressing constraints which cannot
be captured using vanilla XSD.  It
is true that SCA specifications quite generally have constraints of this
kind.

The question for the liaison committee
is: should Schematron get adopted by all of the SCA specifications for
expressing constraints on XML structures?
  It would seem preferable for this to be all-or-nothing for the SCA
specs
as a whole - either they all use Schematron
or none of them should, for consistency sake.



Here is the original Issue as raised
to the BPEL TC:

--------------------------------
DESCRIPTION: There are several places in the document
where we make

statements limiting the usage of our defined XML items.  An example
from

Section 3.3, where sca-bpel:service and sca-bpel:reference are defined:

"A process MUST NOT include both attributes on a single partnerLink."
 

This kind of restriction can not be encoded in XML Schema intuitively,

so we don't.  Furthermore, there is an implicit restriction that these

attributes are only to be used on a partnerLink, but again, we don't

state that formally.


PROPOSAL: Define SchemaTron rules in our specification that formalize

the constraints that are now limited to either informal verbal

constraints, or implied constraints.
---------------------------------


Yours,  Mike.


Strategist - Emerging Technologies, SCA & SDO.

Co Chair OASIS SCA Assembly TC.

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