Yes - and if you want to go one further, ITEM_LIST is nothing more than a special case of ITEM_TREE as well. Modelling this explicitly hasn't been extremely useful I believe, especially if weighed against your evolution argument.
Sebastian Am 04.10.2011 01:42, schrieb Heather Leslie: > 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
