On 14/06/2013 12:19, Diego Bosc? wrote: > Well, in ADL specialization allows extension > > >From here > >(http://www.openehr.org/wiki/pages/viewpage.action?pageId=196633#openEHRADL&AOM1.5-SpecialisationSemantics) > "extensions, i.e. object constraints added to a container attribute > with respect to the corresponding attribute in the parent archetype, > but only as allowed by the underlying reference model." > > So new nodes that change completely the meaning can be added. >
They can't change the meaning of any existing specialised node. 'New' nodes aren't really new; they're just more data that were not defined by constraint by any of the parent archetypes of the current archetype. Often this is some specific item of context data relevant only at a deep level, or it might be something specific to the clinical purpose, e.g. cancer staging as a specialisation of diagnosis. That said, as far as I know, the addition of 'new' nodes, as opposed to extra children of an existing node is pretty rare (would be interesting to report on this in the ADL WB I guess). So to be clear, there is nothing abnormal about such nodes: they are normal archetype nodes that happen to be introduced for the first time in a non-top-level archetype. Of course, wherever there is a freedom, it can be exploited in a bad way - that's just bad modelling. It's always possible to do something badly, but I don't think that's a reason for a wholesale ban. If there are users or communities that want to force all archetype specialisation to be strictly children of previously archetyped nodes, it would be easy to make the tool enforce this. This is what next generation template designer tools should do. - thomas
