FHIR Chat · Slicing of Coding element

Stream: implementers

Topic: Slicing of Coding element

Joel Francis (Jun 21 2019 at 16:51):

Is it conformant/possible to slice the "Coding" element of the CodeableConcept so I can make sure I am expecting a certain value as the first instance?

Eric Haas (Jun 21 2019 at 17:16):

yes... see the documentation on Profiling and the ElementDefinition definition. Tools like Forge should handle this

Jean Duteau (Jun 21 2019 at 17:18):

Is it conformant/possible to slice the "Coding" element of the CodeableConcept so I can make sure I am expecting a certain value as the first instance?

Yes, but why would you want to impose an order on the coding elements? As long as the system or value you are looking for is present, wouldn't that be enough?

The problem with imposing order is that if I have two profiles that each impose order but, other than order, I would be compliant, I now have to create two separate instances. You'll be much nicer to the implementer community if you just say "such-and-such value or system must be present" instead of "it must be the first instance".

Joel Francis (Jun 21 2019 at 17:24):

Is it conformant/possible to slice the "Coding" element of the CodeableConcept so I can make sure I am expecting a certain value as the first instance?

Yes, but why would you want to impose an order on the coding elements? As long as the system or value you are looking for is present, wouldn't that be enough?

The problem with imposing order is that if I have two profiles that each impose order but, other than order, I would be compliant, I now have to create two separate instances. You'll be much nicer to the implementer community if you just say "such-and-such value or system must be present" instead of "it must be the first instance".

ahhhhh good point @Jean Duteau

Joel Francis (Jun 21 2019 at 17:25):

yes... see the documentation on Profiling and the ElementDefinition definition. Tools like Forge should handle this

Thanks @Eric Haas

Rob Hausam (Jun 21 2019 at 18:53):

Agree with @Jean Duteau about not making any expectations regarding the order of the Coding repetitions in a CodeableConcept.

John Silva (Jun 21 2019 at 20:17):

I had a situation where there were multiple coding elements that had the same coding system, though I think this was for multiple categories. One 'hack' was to use the text property to differentiate them.

Eric Haas (Jun 21 2019 at 22:49):

Or the value set

Lloyd McKenzie (Jun 22 2019 at 02:38):

@Joel Francis It's actually non-conformant to assert meaning to the order of elements. If you're not asserting meaning, but just saying "put mine first", that's conformant, but it's a very bad practice - because you're essentially saying "please create a custom interface for me (with all the attendant development, testing and ongoing maintenance costs) so that I can avoid the cost of of writing code once that searches through the list to find the coding I need". So please don't make requirements about sort order for anything where order isn't defined as having meaning. (E.g. given names, address lines, etc.)

Joel Francis (Jun 23 2019 at 01:10):

Joel Francis It's actually non-conformant to assert meaning to the order of elements. If you're not asserting meaning, but just saying "put mine first", that's conformant, but it's a very bad practice - because you're essentially saying "please create a custom interface for me (with all the attendant development, testing and ongoing maintenance costs) so that I can avoid the cost of of writing code once that searches through the list to find the coding I need". So please don't make requirements about sort order for anything where order isn't defined as having meaning. (E.g. given names, address lines, etc.)

Thanks @Lloyd McKenzie