CDA R3 avoid xsi:type

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Submitted by: Rick Geimer	Revision date: August 31, 2009
Submitted date: August 31, 2009	Change request ID: <<Change Request ID>>

Issue

Requiring the use of the xsi:type attribute is problematic. First, it binds CDA to the XML Schema language (other schema languages, like RelaxNG, do not support xsi:type), and also many XML tools to not support this XML Schema specific attribute.

Recommendation

• Create clones of the <value/> element (inside an observation) that are pre-bound to specific datatypes, i.e. <physicalQuantity/> would be pre-defined as a PQ.

Rationale

Creating named clones for each datatype allowed in CDA would limit our dependence on the XML Schema language, and also improve tool compatibility.

For more reasons why the use of xsi:type is often frowned upon, refer to Norm's blog entry on the subject: http://norman.walsh.name/2004/01/29/trainwreck.

Resolution

(Resolution is to be recorded here and in the referenced minutes, which are the authoritative source of resolution).