DV_URI vs DV_IDENTIFIER for non-locator URIs

Specifications
1

According to RFC 3986, a URI can be an identifier without having to also be a locator. Is this also the intent for the DV_URI data type? If so, how does this mesh with DV_IDENTIFIER?

2

The main difference is that:

  • a URI can (assuming it is correct) be resolved to some machine obtainable resource, e.g. an online document, a site, etc
  • a DV_IDENTIFIER captures the identifier of some real world object such as a human, a driving license, a prescription etc. which is issued by some issuer. There is no implication of whether it can be ā€˜resolvedā€™ by anything other than the issuing organisation (e.g. US Social Security, etc), and no implication of anything being available online (even though such things mostly are today, but youā€™d be surprised in the US ā€¦)
3

But does that include a uri that does not actually resolve to a location?

@siljelb can you give an example of what you are trying to identify/connect?

I do think we may have to do something to make it easier to express typed references as per FHIR. OBJECT_REF would do the job but it has no equivalent DV_ for archetype use. or can we modify DV_URI to support this? Ignore if this not your requirement - Iā€™ll re-ask the question elsewhere!!

4

That was what I was wondering about too, thanks Ian!

The starting point for my question was this change request: Cluster Archetype: Laboratory analyte result [openEHR Clinical Knowledge Manager]

The CR is suggesting using both the DV_IDENTIFIER and the DV_URI as data types, which led to the question of how these two should be used in relation to one another. Do we by ā€œURIā€ really mean ā€œURLā€, even though the class description clearly mentions RFC-3986, which explicitly allows URIs that are not also URLs?

5

A URI can be incorrect, like anything else. RFC 3986 doesnā€™t state anything about resolution, only about URI syntax. A URI supplied to a resolving server may result in a 404 (if itā€™s an HTTP server), or any other failure equivalent.

Also URIs donā€™t resolve (for the ones that do resolve) to locations, only to resources, e.g. a document, a SNOMED code, whatever it may be.

The intent of a URI is that it resolves to something in the online world, nearly always via HTTP protocol; thatā€™s the difference with DV_IDENTIFIER, which has no assumption about any online anything; it is assumed to be resolvable by whatever means are available, e.g presenting at the reception of the state DVLA, Social Security office; making phone calls, and possibly specific online systems, but there is no general expectation that an SSN or a veterans number can be just put into a browser and get a sensible result.

6

@siljelb to confuse things a bit more :wink: I guess you might have noted that URNs are also URIs (but not necessarily resolvable). Feel free to help me/us think about how they are best used in openEHR, see:

P.s. also somewhat related: Usage of OID, URI (URL/URN) in DV_IDENTIFIER fields?

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