On 11/04/2016 11:07, Bjørn Næss wrote:
But if we want to avoid double results in querying, we need some sort
of 'is_derived' or 'is_copy' marker (and a link to original content)
on the copy. At least that's where I got to the last time I thought
about it.
Yes – I think we need some kind of marked. We have been thinking about
adding this to the link. Some kind of “link to self”. Then to avoid
duplicates you MUST include that in every AQL. This is why we ended up
with the proposal of a Composition category which solely of re-used
(copies) data.
I'm not sure if this has the flexibility you (we) really want thought
does it? It means that the entire Composition has to be treated as
duplicate info to be excluded from query evaluation.
The same pattern could be applied on several levels (ENTRY, CLUSTER).
I.e. a Blood Pressure with an attribute ‘is_copy’ should by default be
excluded from AQL queries.
Something like that?
Right. If we did it in the most general fashion possible, LOCATABLE
<http://www.openehr.org/releases/RM/latest/docs/common/common.html#_archetyped_package>
could have a Boolean flag 'is_copy'. But then you have a False Boolean
on 99% of all data, which is not great data design. If we say that any
copy has to have a LINK attached pointing to what it is a copy of, then
your suggestion above is better (if I understand correctly) - put an
'is_copy' flag there. It could be argued that 'meaning' should encode
whether something is a copy or not, but I think a separate flag would be
better, and in any case 'meaning' might still carry different reasons
for making copies.
- thomas
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