Stream: implementers
Topic: FHIR support for V2 "" active null
Alexander Henket (Apr 10 2018 at 14:07):
We are mapping from HL7 V2 to FHIR. How do we describe an ActiveNull within FHIR. (The order to delete a field from the database)? @Simone Heckmann
Stefan Lang (Apr 10 2018 at 14:11):
Being far from a v2 geek: wouldn't that be a patch in FHIR?
Nick Hatt (Apr 10 2018 at 14:39):
From https://www.hl7.org/fhir/comparison-v2.html
Nulls and update modes: In HL7 v2, "action" codes can determine whether particular segments represent information to be added, updated or deleted. Fields can be populated with "null" (two consecutive double-quotes with no other characters) to note a field is to be deleted. An omitted element or repetition is generally interpreted as "retain existing data unchanged". This contrasts with the FHIR approach of requiring all data to be present as a snapshot. Systems will either need to build in logic to generate a full snapshot of each resource or consider using the Patch Operation instead.
Bigger picture: the v2 null is not REST-ful. I'd lean more towards the "all data present as a snapshot" solution vs the PATCH solution. PATCH could get really messy - do you PUT all the normal fields, then PATCH the nulled field?
Alexander Henket (Apr 10 2018 at 15:18):
If any resource equals a snapshot situation for that resource (which is not an unreasonable assumption since resources used to be the smallest atom for change, until PATCH came along), then I guess anything not populated in the resources is effectively nullified?
Lloyd McKenzie (Apr 10 2018 at 17:05):
Anything not populated is "requested" to be nullified. However, the server has the right to ignore the request - as they do in v2.
Alexander Henket (Apr 10 2018 at 17:11):
Sounds fair. I think that covers my question although there's always room for detailed thoughts
Last updated: Apr 12 2022 at 19:14 UTC
