FHIR Chat · Implementing _sort

Stream: implementers

Topic: Implementing _sort

Richard Kavanagh (Jan 12 2020 at 23:01):

When implementing _sort (http://hl7.org/fhir/R4/search.html#_sort).

Is it expected that the server can sort on any element of a resource? Surely that would be quite expensive from the database perspective.

Lloyd McKenzie (Jan 12 2020 at 23:44):

You can sort on any search parameter supported by the server

Richard Kavanagh (Jan 12 2020 at 23:49):

Thanks @Lloyd McKenzie . I guess the client just has to ask for what they want and hope the server supports it. i.e. there is no provision to declare what is supported in the CapabilityStatement.

Lloyd McKenzie (Jan 12 2020 at 23:59):

I think the general expectation is that if you support _sort and you support a given search parameter, you should be able to sort on that search parameter (presumably if you can search by it, you'll have it indexed, so sorting by it shouldn't be a significant cost).

dsh (Jan 22 2020 at 05:02):

You can sort on any search parameter supported by the server

@Lloyd McKenzie is there an easy way to list search parameters supported by HAPI FHIR JPA Server ?

dsh (Jan 22 2020 at 05:04):

I am trying to user _sort on Observation like /hapi-fhir-jpaserver/fhir/Observation/?_count=10&_sort=effectiveDateTime'

but I get this error

{
  "resourceType": "OperationOutcome",
  "text": {
    "status": "generated",
    "div": "<div xmlns=\"http://www.w3.org/1999/xhtml\"><h1>Operation Outcome</h1><table border=\"0\"><tr><td style=\"font-weight: bold;\">ERROR</td><td>[]</td><td><pre>Unknown sort parameter
'effectiveDateTime'</pre></td>\n\t\t\t\t\t\n\t\t\t\t\n\t\t\t</tr>\n\t\t</table>\n\t</div>"
  },
  "issue": [
    {
      "severity": "error",
      "code": "processing",
      "diagnostics": "Unknown sort parameter 'effectiveDateTime'"
    }
  ]
}