[openEHR SEC] AQL FROM & CONTAINS with many entries

Technical (archive)
1

Hi all, another question about AQL and CONTAINS.

Most of the AQL samples use just one branch in the FROM clause, like:

EHR CONTAINS COMPOSITION CONTAINS OBSERVATION.

I’m wondering what would be the correct FROM notation when more than one ENTRY is needed. Some examples below.

SELECT o1/data[…]/…/value, o2/…, …
FROM
COMPOSITION c [archid] CONTAINS OBSERVATION o1 [archid2],
COMPOSITION c [archid] CONTAINS OBSERVATION o2 [archid3],
COMPOSITION c [archid] CONTAINS OBSERVATION o3 [archid4]
WHERE …

SELECT o1/data[…]/…/value, o2/…, …
FROM
COMPOSITION c [archid]
CONTAINS OBSERVATION o1 [archid2] AND
CONTAINS OBSERVATION o2 [archid3] AND
CONTAINS OBSERVATION o3 [archid4]
WHERE …

Thanks!

2

Hi Pablo,

I hope I understood correctly:

select
a_a/data[at0002]/events[at0003]/data[at0001]/items[at0004]/value,
a_b/data[at0001]/events[at0006]/data[at0003]/items[at0004]/value
from EHR e
contains COMPOSITION a
contains (
OBSERVATION a_a[openEHR-EHR-OBSERVATION.body_temperature.v1] and
OBSERVATION a_b[openEHR-EHR-OBSERVATION.blood_pressure.v1])

this should be the right way to express the query. I think an account for EHRSCAPE could be of help if you want to dig deeper into AQL.

Cheers,

Birger

3

X contains (y and z and t)

The paranthesis are optional above but would help avoid ambiguity when we have

X contains y and z contains t and o
Is it:
X contains y and (z contains t) and o
Or
X contains y and (z contains t and o)

??

As you can see the paranthesis help define the containment structure

4

Also see this, just in case it may help clarify relevant Qs: https://github.com/serefarikan/aql-discussion

5

Thanks, my goal besides understanding the syntax is to improve the current spec, so I’m testing some use cases against the AQL spec instead of using specific implementations.

Cheers,
Pablo.

6

gotcha, makes sense, I need to check the grammar in the specs to see where parenthesis can be used.

7

OK, makes sense! Please excuse me for stating the obvious :slight_smile:

Birger