Stream: implementers
Topic: Observation custom search - query vs operation
Tom Pick (Oct 31 2018 at 13:11):
Hi all. I have some custom search behaviour to implement for Observation and I'm wondering whether to user $foo or _query=foo. I had assumed _query (since I am still querying for data) but I see that $lastn is an operation instead, which feels very much like a "query" to me.
Any pointers on best practice for selecting the right one much appreciated - I'm struggling to spot the difference between the two.
Lloyd McKenzie (Oct 31 2018 at 13:57):
@Grahame Grieve ?
Grahame Grieve (Oct 31 2018 at 19:57):
I'm not sure. _query has kind of fallen out of interest, and we've been defining operations instead
Lloyd McKenzie (Oct 31 2018 at 20:10):
I don't really understand how they're different. Perhaps we should consider _query for deprecation in R5?
Tom Pick (Oct 31 2018 at 21:43):
I notice CDSS is an example use case for _query: https://www.hl7.org/fhir/usecases.html#7.8.3.1 Not sure if anyone is using it that way? Anyway thanks both, that's nudged me towards $foo for now.
David Waters (Nov 15 2018 at 15:13):
I notice CDSS is an example use case for _query: https://www.hl7.org/fhir/usecases.html#7.8.3.1 Not sure if anyone is using it that way? Anyway thanks both, that's nudged me towards $foo for now.
We are looking at CDSS implementation at the moment, but are using ServiceDefinition and GuidanceResponse, as recommended by the CDS working group, and have not looked at _query for this, so would also be interested if anyone is actually using it in this way
Last updated: Apr 12 2022 at 19:14 UTC
