Searching for Data

FHIR Search Extensions

In addition to implementing most of the FHIR Search specification, Opala implements the following extensions:

_source

An additional search parameter called _source can be used to search for resources based on information about the system or request that created the resource. See Storing Source Information.

%now

Date searches can be performed relative to "now" using the %now parameter value. For example, to search for Procedures with a date later than now, you can search for /Procedure?date=ge%now.

Note the % would need to be URL-escaped so the actual URL will be /Procedure?date=ge%25now.

The way this works is by substituting %now with the current date and time in the standard FHIR format yyyy-MM-ddTHH:mm:ss before submitting it to the FHIR Storage module.

%today

Similarly, date searches can be performed relative to "today" using the %today parameter value. %today works the same as %now except that it searches as a date type as opposed to a dateTime type.

Unsupported Search Parameters

Opala does not currently support the _containedType FHIR Search parameter, or the _contained=both directive. See the Index Contained topic in Smile CDR's documentation for information on indexing contained resources.

Limitations

Opala searches may not correctly process :[type] modifiers if the resource indicated by the modified search parameter is a contained resource. For example, consider the following search.

http://localhost:8000/Observation?subject:Patient.organization.name=HealthOrg

Suppose Observation/A has a reference to Device/B, which in turn has a reference to Organization/C, and Organization/C has the name "HealthOrg".

In this case, Observation/A will not be included in the search result, because the subject search parameter is restricted to Patient resources. However, if Observation/D has a reference to #contained-device, which also refers to Organization/C, then Observation/D will be included in the search result, because we cannot apply the type restriction to contained resources.