On 26-01-16 10:15, 吕旭东 wrote:
We haven't convert RM to relational model, it will cause lots of JOIN
operation and low performance. Actually, we using "storage template",
which is a specialization of archetype for storage purpose, and is
generated automatically according to existing multiple templates (If
more templates are added, the "storage template" will be updated, but
in real case, it will not be updated too often).
So, if I understand, it is an -on the fly- optimization. So to say if in
an archetype something is not there, then there is no storage needed to
store that, no query needed to handle that (because it is not there). So
you store every archetype with its own optimization in an own structure?
You optimize the RM for a specific archetype
If I understand it well, this is a very original approach.
Excuse me for reading your document to quick. I will now read it more
carefully
Thank you very much for sharing.
Bert
Best Regards
Xudong
2016-01-26 1:42 GMT+08:00 Bert Verhees <[email protected]
<mailto:[email protected]>>:
Another problem is you have to convert your object oriented model
(which RM is) to a relational model, which becomes complex in
converting templates/aql to SQL. I have been that way. More then
five years ago I left it. It is difficult doable, if you want a
full featured openehr kernel. I would never recommend going this
way, unless someone has a really smart idea.
It can work for a light featured openehr light derived application
model.
Best regards
Bert
Op 25 jan. 2016 15:26 schreef "[email protected]
<mailto:[email protected]>" <[email protected]
<mailto:[email protected]>>:
I talked about this approach with a colleague from China
during MEDINFO. The problem is your schema grows with your
archetypes. Also, that storing data from many templates that
don't use all the fields in the archetype, will generate
sparse tables (lots of null columns). I told him it was easier
to do an ORM from the IM, because the schema doesn't change
and allows to store data from any archetype/template. But they
already have a system working this way.
Sent from my LG Mobile
------ Original message------
*From: *Ian McNicoll
*Date: *Mon, Jan 25, 2016 10:06
*To: *For openEHR technical discussions;
*Subject:*Archetype relational mapping - a practical openEHR
persistence solution
Interesting paper from China
http://bmcmedinformdecismak.biomedcentral.com/articles/10.1186/s12911-015-0212-0
Ian
Dr Ian McNicoll
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Co-Chair, openEHR Foundation [email protected]
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Director, freshEHR Clinical Informatics Ltd.
Director, HANDIHealth CIC
Hon. Senior Research Associate, CHIME, UCL
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