Dear all,

I am currently studying the set of HL7-v3-XML messages.

What surprised me is that different of these messages (each of them =
defined by its own standard) all have the same namespace associated =
("urn:hl7-org:v3").
So we find the same default namespace for the CCD/CDA, aECG and for the =
SPL standard - this though the root elements are really different:
- "ClinicalDocument" for CDA/CCD
- "Document" for SPL
- "AnnotatedECG" for aECG

So we find in the instance documents .e.g.:

CDA: <ClinicalDocument xmlns="urn:hl7-org:v3" ...
SPL: <Document xmlns="urn:hl7-org:v3" ...
aECG: <AnnotatedECG xmlns="urn:hl7-org:v3" 

I realize each of these three "standards" use a set of common elements =
and attributes, which are defined in schemas that are shared, but the =
main schema is different, and the composition (child elements) of the =
root elements is different each time.

Is this "good practice" or should have each of these "standards" =
essentially have their own namespace, and then have the common/shared =
elements in another, shared namespace ?

Your comments are appreciated.

Jozef

Jozef Aerts