Please remove me from this mailing list. > Kind Regards, > > Andrej Orel > > --- ns shivam <nsshivam at yahoo.co.uk> wrote: > > kindly remove me from this mailing list > > > > Thomas Beale <thomas at deepthought.com.au> wrote: > > > > Tim Churches wrote: > > > > >On Tue, 2003-08-05 at 07:27, Thomas Beale wrote: > > > > > > > > >>Not sure what you mean by "inefficient".. > > >> > > >> > > > > > >Well, I have changed my address several times > > during my life, but not my > > >sex or my name. This can be modelled by either > > keeping an address > > >history within my demographic record (that is, > > explicitly modelling the > > >time domain), or by keeping timestamped versions of > > my entire > > >demographic record. openEHR seems to adopt the > > latter approach. > > > > > Actually, it doesn't, but it's not obvious I agree. > > If you look at the > > common RM > > > (http://www.openehr.org/Doc_html/Model/Reference/common_rm.htm) > > you will > > see that there is a class VERSION_REPOSITORY and a > > class VERSION. > > The former is a functional interface to the stack of > > versions for one > > versioned entity, which might be a PARTY, a > > TRANSACTION of whatever. But > > it does not say how to implement this. A > > space-inefficient, but simple, > > implementation would be to just have successive > > complete copies. A more > > efficient way would be to adopt the algorithm used > > in versioning object > > databases which only stores new objects in each > > version, and uses > > special markers for deleted objects. Normally this > > would be done > > backwards, so that it is always the most recent > > version that is > > complete, since it is the one most likely to be > > retrieved all the time. > > > > >That > > >approach is less efficient space-wise, but that > > hardly matters these > > >days. It is more efficient if the (medico-legal) > > query is "what was my > > >demographic record at date yyyy-mm-dd?" Much less > > efficient if the query > > >is "how many times did I change my address?". > > > > > for a single patient, neither of these is much work > > - it's trivial, > > regardless of the representation of versions > > > > > Very, very inefficient if > > >the query is "what is the mean number of address > > changes in the entire > > >population?". I am thinking from an aggregate > > epidemiological POV, not a > > >clinical/medico-legal individual patient POV. But > > then, satisfying the > > >former POV is what data warehouses, populated from > > EHRs, are for... > > > > > sure - and I agree - this is what data warehouses > > are for. This kind of > > querying requires forethought. If you know you are > > going to be > > collecting say 50 statistica, including "number of > > times change > > address", then you start designing software agents > > to capture the data > > as they go into the EHR, e.g. a simple address > > change counter for your > > query. Then generating the result is trivial. > > > > - thomas > > > > > > - > > If you have any questions about using this list, > > please send a message to d.lloyd at openehr.org > > > > > > Dr.N.S.Shivam MS,FRCS,DNB > > > > Head Healthcare Business development (Provider) > > HCL Perot Systems > > Plot No3, Sector 125, > > Noida > > Ph: 09811901903 > > > > > > --------------------------------- > > Want to chat instantly with your online friends? Get > > the FREE Yahoo!Messenger > > > __________________________________ > Do you Yahoo!? > The New Yahoo! Search - Faster. Easier. Bingo. > http://search.yahoo.com > - > If you have any questions about using this list, > please send a message to d.lloyd at openehr.org >
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