How to group items

[xamelon]

Description

Form is a list of questions grouped together around specific problem.
Form is used to capture data from respondents (patients,practitioners, etc...)
There are forms and fields that can be grouped and merged logically and visually

Use cases

• I have several questions about patient (name, address, gender)
  and I want this data be stored together
• I have several questions that should be displayed depending on answer to the previous question.

  in this case I want to write rule only for group not for each field

FHIR has special item type for this: group:

[{:type "group"
  :linkId "blood-pressure"
  :item [{:linkId "systolic"}
         {:linkId "diastolic"}]}]

Current solution in Aidbox SDC is to use zen/map in document schema:

:blood-pressure {:type zen/map
                 :keys {:systolic {...}
                        :diastolic {...}}}

Problem with current solution in Aidbox SDC is that you can't be confident that
this is a group. zen/map is also a Quantity, Coding, Reference questions.

Questions

• How grouping questions does affect data schema?
• how to query results?
• how does this affect rules?
• how to convert our form description <> Questionnaire/QuestionnaireResponse

Approaches

• do not group items
• special widget type 'group'

[xamelon]

Do not group items

how does this affect data schema?

Simple flat data structure.

[{:id "bp-systolic"}
 {:id "bp-diastolic"}]

How to query results?

Query form result is also easy.

select * from QuestionnaireResponse, jsonb_array_elements(resource->'items') items
where item->>'id' == 'bp-systolic'

How does this affect rules?

Since we can't join several fields into group, we have to write rule for each fields,
which results to duplicate code.

For example we have several questions belongs to alcohol usage. And we want to show them only
if patient says that he takes alcohol. In this case we have to repeat enableWhen logic for each question.

How to convert our form description <> FHIR Questionnaire/QuestionnaireResponse

Converting to QuestionnaireResponse is straightforward. We don't need handle nested items.

(assoc qr :bp-systolic (get resp :bp-systolic))

But importing/converting Questionnaire also possible, but need to flatten Q structure
in case Questionnaire has groups.

(assoc form :bp-systolic (find-item q :bp-systolic))

[xamelon]

Special widget type group. All childrens are placed under :item key

This approach exactly the same as FHIR Questionnaire/QuestionnaireResponse

How does this affect data schema

[{:id "blood-pressure"
  :type "group"
  :item [{:id "systolic"}
         {:id "diastolic"}]}]

How does this affect rules?

In this case we can easily hide/show group of questions.

[{:id "alcohol-use"
  :type "boolean"}
 {:id "alcohol-questions"
  :type "group"
  :item [{:id "alcohol-type"}
         {:id "frequency"}]}]

How to query results?

Quering results may be tricky if we have deep nesting.
In simpliest case:

select qr.id, item->'item' from questionnaireResponse qr, jsonb_array_elements(resource#>'{item}') item
where item#>>'{item,0,linkId}' = '8310-5'

Or use jsonb_path_query:

select qr.id, item.* from questionnaireResponse qr,
       	      	     	  jsonb_path_query(qr.resource, '$.item[*].item[*] ? (@.linkId == "8310-5")') item

How to convert our form description <> FHIR Questionnaire/QuestionnarieResponse

This approach is clone of FHIR approach. So we don't need to do anything special to convert in/to FHIR.

(assoc qr :blood-pressure (get form :blood-pressure))
(assoc form :blood-pressure (get qr :blood-pressure))