FHIR Chat · Composite search parameter expressions

Stream: implementers

Topic: Composite search parameter expressions

Lee Surprenant (Dec 10 2019 at 20:08):

I'm trying to determine what is the proper behavior for SearchParameters of type composite.
Consider Group-characteristic-value which has an expression like Group.characteristic and the following components:

[
  {
    "definition": "http://hl7.org/fhir/SearchParameter/Group-characteristic",
    "expression": "code"
  },
  {
    "definition": "http://hl7.org/fhir/SearchParameter/Group-value",
    "expression": "value"
  }
]

The expression there led me to believe that the value component could be ANY of the choice elements for Group.characteristic.value[x]

However, when I look up http://hl7.org/fhir/SearchParameter/Group-value I see that this parameter restricts the values to just CodeableConcept and boolean values: (Group.characteristic.value as CodeableConcept) | (Group.characteristic.value as boolean)

Can anyone confirm whether Group-characteristic-value is applicable to non-token values?

Lee Surprenant (Dec 10 2019 at 20:23):

https://www.hl7.org/fhir/searchparameter-definitions.html#SearchParameter.component.expression says

This expression overrides the expression in the definition and extracts the index values from the outcome of the composite expression.

But if I follow that advice, then my system doesn't like non-code values (Quantity, Range, or Reference) because it doesn't know how to extract those into a search parameter of type token.

Grahame Grieve (Dec 10 2019 at 22:10):

this is an error in the definition of Group. The expression on group is value but should be (value as CodeableConcept) | (value as boolean)

Grahame Grieve (Dec 10 2019 at 22:11):

do you want to make a task to fix this?

Lee Surprenant (Dec 11 2019 at 02:11):

opened https://jira.hl7.org/browse/FHIR-25297 - Group-characteristic-value search parameter should be scoped to CodeableConcept | boolean

Last updated: Apr 12 2022 at 19:14 UTC

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