I model using ITEM_TREE as default in every archetype, except where we might need a table structure.
So I always aim to allow for maximal flexibility as the archetype evolves... and in almost every situation it does. Heather >-----Original Message----- >From: openehr-clinical-bounces at openehr.org [mailto:openehr-clinical- >bounces at openehr.org] On Behalf Of Rong Chen >Sent: Tuesday, 4 October 2011 6:29 AM >To: For openEHR clinical discussions >Cc: openehr technical >Subject: Re: Questions about the necessity of ITEM_SINGLE > >Hi Pablo, > >I agree with your analysis here especially the last one regarding evolution of >archetypes. > >Regards, >Rong > >On 3 October 2011 16:23, pablo pazos <pazospablo at hotmail.com> wrote: >> Hi everyone, >> >> I've been studying how to simplify the ITEM_STRUCTURE model to enhance >> the persistence performance of our Open EHR-Gen project >> (http://code.google.com/p/open-ehr-gen-framework). >> >> Now I'm reaching a point in which I doubt about the necessity of >> ITEM_SINGLE in the RM (as a subclass of ITEM_STRUCTURE) and I want to >> expose some arguments and hear your comments about it. >> >> Semantic argument: As I understand ITEM_SINGLE, the semantics of this >> class are the same as an ITEM_LIST or ITEM_TREE with only one ELEMENT, >> I mean >> that: the semantics of ITEM_SINGLE is just a matter of cardinality (=1). >> >> Practical argument: in practice, an ITEM_SINGLE is like using an >> ELEMENT as an ITEM_STRUCTURE. And if we have only TREEs, LISTs and >> TABLEs, the interface of each class can be the same, like: getItems(), >> setItems(), the ITEM_SINGLE breaks that with getItem() and setItem(). >> >> Evolution argument: If I have an archetype with an ITEM_SINGLE, but >> the concept modeled with this archetype needs to change adding more >> nodes to the archetype, I need to change the ITEM_SINGLE to another >> ITEM_STRUCTURE, but if the archetype is modeled with an ITEM_TREE, I >> can add any nodes without changing the ITEM_STRUCTURE type. I think >> this way is more simple to create new archetypes with backwards >compatibility. >> >> >> What do you think? >> >> -- >> Kind regards, >> Ing. Pablo Pazos Guti?rrez >> LinkedIn: http://uy.linkedin.com/in/pablopazosgutierrez >> Blog: http://informatica-medica.blogspot.com/ >> Twitter: http://twitter.com/ppazos >> _______________________________________________ >> openEHR-clinical mailing list >> openEHR-clinical at openehr.org >> http://lists.chime.ucl.ac.uk/mailman/listinfo/openehr-clinical >> > >_______________________________________________ >openEHR-clinical mailing list >openEHR-clinical at openehr.org >http://lists.chime.ucl.ac.uk/mailman/listinfo/openehr-clinical
