Hi >> So the HL7 qualifier thing is (mostly) simply a predefined expression syntax >> for >> post-coordination. It overlaps with terminologies that have their own >> expression >> syntax - such as SNOMED. The HL7 model does allow a richer expression of the >> details of the construction of the expression - such as which text led to >> which >> qualifier, but this is, as I said, for precision and pedantry. Not for normal >> everyday use. So the question is, is it better to squeeze things into the >> text of a CODE_PHRASE, or to squeeze things into xml? Either way, you need to >> have a terminology service to do anything useful with the data. So what's the >> difference? I don't have a strong feeling about that. >> >> > I think the main point here is that CODE_PHRASE and other similar parts > of the openEHR model (and this applies to any model at all) that are > modelled using an internal syntax string (which could itself be XML - > who is to say it isn't?) implies quite strongly that the contents of the > relevant attributes (CODE_PHRASE.code_string) are the business of some > outside system, not openEHR itself. In purely technical terms, using a > class modelling approach for such things may be the same as using the > syntax approach - i.e. any code_string generated by a terminology server > can most likely be modelled using a class model as well, something like > HL7's classes. But.... > * there is always the possibility that it can't - because the class > model commits to one idea of terminology coordination, while the syntax > approach leaves it open
do we know of any case? > * the information model shouldn't dictate to the terminology environment > how to represent its artefacts. I have some sympathy for this. I have been tempted to toast the qualifier and push everything into code as you guys have done, for the same reasons. But I haven't found any case where the existing qualifier syntax is a problem, and there is accepted requirements for originalText on the qualifiers (at least, HL7 has accepted them). SO I didn't toast it, but I did say in the openEHR mapping that you'd collapse the qualifiers into the code phrase. I don't have a strong feeling for whether this would be necessary or appropriate for 13606 Grahame _______________________________________________ openEHR-technical mailing list openEHR-technical at openehr.org http://www.chime.ucl.ac.uk/mailman/listinfo/openehr-technical
