AQL questions

Bjørn Næss bna at
Fri Apr 26 03:43:41 EDT 2019

Thomas answered the CONTAINS operator. 

I am not sure how to best answer your second question. I will try the following :-) 

The node predicates as below: 

*    c2/items[at0002]/items[at0001]/value/magnitude
*    o/data[at0001]/events[at0002]/time

Here the "c2" and "o" is a reference to a path in the Composition, and the reference is defined in the FROM part of the AQL. The "c2" is synonymous with the following path: 

"c2" == "/content[openEHR-EHR-OBSERVATION.laboratory_test.v1]/data[at0001]/events[at0002]/data[at0003]/items[openEHR-EHR-CLUSTER.laboratory_test_panel.v1]"

Which gives "c2" + "path" to be: 

"/content[openEHR-EHR-OBSERVATION.laboratory_test.v1]/data[at0001]/events[at0002]/data[at0003]/items[openEHR-EHR-CLUSTER.laboratory_test_panel.v1]/ /items[at0002]/items[at0001]/value/magnitude"

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Bjørn Næss

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-----Original Message-----
From: openEHR-technical <openehr-technical-bounces at> On Behalf Of Georg Fette
Sent: torsdag 25. april 2019 19:30
To: openehr-technical at
Subject: Re: AQL questions

Hi Bjørn,
Thank you for your answers. They make me assume that the CONTAINS-operator is recursive because in your second query you ommited the part with "CONTAINS OBSERVATION o[openEHR-EHR-OBSERVATION.laboratory_test.v1]". Is this assumption correct ? This would make writing AQL a lot simpler.
Another assumption I have is that the predicate namespaces always relate to the aliased archetype the path they are used within starts with. In your first query you use at0001 and at0002 each two times but they seem to have different meanings.

Dipl.-Inf. Georg Fette      Raum: B009
Universität Würzburg        Tel.: +49-(0)931-31-85516
Am Hubland                  Fax.: +49-(0)931-31-86732
97074 Würzburg              mail: georg.fette at

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