automatic demotion of lists in AQL ?

Georg Fette georg.fette at
Fri Apr 26 07:27:19 EDT 2019

Is it allowed to use an element that is allowed to appear multiple times 
within a path ?
For example in the query

SELECT a/items[at0001]/value
     FROM EHR e
         CONTAINS CLUSTER a[openEHR-EHR-CLUSTER.laboratory_test_analyte.v1]

the field items[at0001] may appear 0..* times. Thus the access to the 
value field is not properly defined from a type checking point of view.
Does the AQL specification allow such constructs and how is this 
situation interpreted ?

Dipl.-Inf. Georg Fette      Raum: B001
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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