dhis2-devs team mailing list archive

[Bob Jolliffe <bobjolliffe@xxxxxxxxx>]

On 16 February 2011 11:41, Ola Hodne Titlestad <olati@xxxxxxxxxx> wrote:
> Hi,
> One thing to have in mind here is that a data element can be captured in
> multiple datasets (but still refer to the same value).
> This has been a popular mechanism to help implementers work around the many
> duplicating forms and still keep the database as clean and consistent as
> possible.
> In this scenario it would be difficult to know which form/dataset actually
> collected the value I guess.
> I know there have been some requests to add more properties to the values,
> e.g. how they were captured, who is the owner etc. but it should be possible
> to accommodate this and still keep the original primary keys / references
> for data values (orgunit, period, data element, catoptioncombo).
> If your grouping of values only concerns how data values are collected and
> transferred and not how they are persisted, then it seems fine to me. This
> is the role of the dataset in today's model.

No its not and that is the shortcoming.  The dataset is a grouping of
dataelements not datavalues.  Hence there is no explicit relationship
between datavalue and dataset.  You can implicitly figure it out by
"calculating" the dataset as a f(dataelement, orgunit) where
periodType you calculate as f(periodid).  But bearing in mind what you
start off with above, even this might be considered a best effort.

All of this is much more entangled than it needs to be but it has
evolved that way and, as Lars says, it won't be changed in a hurry.

Anyway, more later ..

Bob

> Ola
> -------
>
> On 16 February 2011 11:57, Bob Jolliffe <bobjolliffe@xxxxxxxxx> wrote:
>>
>> On 16 February 2011 07:37, Abyot Gizaw <abyota@xxxxxxxxx> wrote:
>> >
>> >
>> > 2011/2/15 Bob Jolliffe <bobjolliffe@xxxxxxxxx>
>> >>
>> >> On 15 February 2011 14:09, Lars Helge Øverland <larshelge@xxxxxxxxx>
>> >> wrote:
>> >> >
>> >> >
>> >> > On Tue, Feb 15, 2011 at 2:34 PM, Jo Størset <storset@xxxxxxxxx>
>> >> > wrote:
>> >> >>
>> >> >> Den 15. feb. 2011 kl. 18.40 skrev Bob Jolliffe:
>> >> >>
>> >> >> > Simple validation seems to work ok.  I get an "Aw, Snap! ..." when
>> >> >> > posting twice with the same period but that is probably something
>> >> >> > you
>> >> >> > are not catching yet.
>> >> >>
>> >> >> Should work now.
>> >> >>
>> >> >> > I don't agree with this.
>> >> >>
>> >> >> I know :) I don't necessarily agree myself, but it is also a matter
>> >> >> of
>> >> >> what is practically possible.. (And it might make sense to have a
>> >> >> simpler
>> >> >> json-oriented web api vs. a more fullfledged xml format for heavy
>> >> >> imp/exp.
>> >> >> Are you coming to Oslo in March by any chance, then we can fight it
>> >> >> out! )
>> >> >>
>> >> >
>> >> > Can you please explain why it is not practically possible to have dxf
>> >> > as
>> >> > the
>> >> > root element?
>> >> > I don't have anything against grouping datavalues in sets to make the
>> >> > format
>> >> > more compact. But, first, we currently don't have any real
>> >> > requirements
>> >> > or
>> >> > use-case where we want to persist the "datavalueset". Second we
>> >> > currently
>> >> > have no support for it in the model. So whats the point of modeling
>> >> > our
>> >> > exchange format this way?
>> >>
>> >> Well partly because this structure models the way data is produced.
>> >> In sets.  Off a form or off an import.  SDMX data for example also
>> >> arrives in sets.  While there is no support in the model it simply
>> >> means that we can lose information regarding the set.  It becomes
>> >> important where you might want to rollback a set or identify where
>> >> some particular has come from.  Currently this is sort of implicitly
>> >> keyed but there are benefits in making it explicit.  For example you
>> >> can't currently trace a datavalue back to whether it was entered
>> >> through a dhis form, whether it arrived from one of Jo's 5000 phone's
>> >> or whether it was imported from iHRIS (or whatever).  You can populate
>> >> the comment of all the datavalues but that's really expensive.
>> >>
>> >> There are also savings to be had on storage by inheriting atttributes
>> >> like period and orrgunit from a dataset rather replicating in each
>> >> datavalue.
>> >>
>> >> It's not a model change I would propose immediately (I think we have
>> >> enough zooks to sort out) but surely it is hard to argue that its not
>> >> the (proverbial) right thing to do.  Meanwhile the way Jo has it in
>> >> his xml looks fine to me.
>> >
>> >
>> > Hmmm... I think if we are to with this datavalueset concept and take
>> > away
>> > orgunit&period from datavalue and leave it with the groupset - we will
>> > be
>> > hitting a big trouble!
>> >
>> > The flexibility we have right now - the way we define Indicators, design
>> > reports,... - is down to the independence of the datavalue. Each and
>> > every
>> > piece of datavalue can stand by itself and make sense - allowing
>> > monitoring
>> > and evaluation people greater flexibility and harmonization.
>> >
>> > Again, with the datavalueset approach mentioned here, we will be against
>> > the
>> > minimum-dataset concept. For me the minimum dataset concept worked
>> > because
>> > users/healthprograms can share dataelement/datavalue.
>>
>> I doubt the trouble would be as big as you think.  But you might be
>> right and could be I'm missing something.  But regarding just posting
>> of data it makes no difference at all other than making the message
>> more efficient.
>>
>> What is minimum-dataset concept?
>>
>> Bob
>>
>> BTW its not really to do with groupset.  But I guess that was a typo.
>>
>> >
>> > Abyot.
>> >
>> >>
>> >> Cheers
>> >> Bob
>> >>
>> >> > Yes we might need it sometime in the future but
>> >> > then we should implement it when we need it.
>> >> > I also find it weird that we really need to implement two parsers for
>> >> > this.
>> >> > More work and more code to maintain.
>> >> > The uuids will go for a new Identifier property for version 2.2 and
>> >> > make
>> >> > things less verbose btw.
>> >> > Lars
>> >> >
>> >> >>
>> >> >> > Your use of DataValueSet here is very welcome - as you know I have
>> >> >> > been advocating this for a while.  Would be nice also to persist
>> >> >> > it
>> >> >> > to
>> >> >> > provide audit (and simplify dtavalue store) but that is maybe too
>> >> >> > much
>> >> >> > for now.
>> >> >>
>> >> >> Yes, that would have to be the next topic. Let's see if anyone else
>> >> >> take
>> >> >> the bait :)
>> >> >>
>> >> >> Jo
>> >> >> _______________________________________________
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>> >> >
>> >> >
>> >>
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>> >
>>
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