[DDI-users] a question about schemes/versions/references

[Joachim Wackerow]

Hi Alerk,

This understanding is correct. A new version of qC triggers a new 
version of the question scheme. Then you have basically two identical 
objects with none-identical identifiers.

You can use different approaches to solve the issue:

Alternative 1:
The QuestionItem for qA and qB can mention the objectSource, which is a 
reference to the object from which the item is being copied.
http://www.ddialliance.org/sites/default/files/documentation/ddi3.1/schemas/reusable_xsd/complexTypes/AbstractIdentifiableType.html#r5

Alternative 2:
qs v2.0.0 could reference qA and qB in qs v1.0.0 where they live.

Alternative 3:
qA and qB could live in a resource package where they can be referenced 
by wave 1 and 2.

Alternative 4:
It is possible to state in the comparison module that two questions 
(here identical, but with different identifiers) are the same

Alternative 5:
With the grouping approach it is possible to push everything, which is a 
candidate for reuse, to a higher level. Then no replication of objects 
takes place.

Dependent from the background one of this solutions is preferable to the 
others. As far as I understand alternative 1 and 3 seem to be good 
candidates. They are not too hard to implement.

Cheers,
Achim

Alerk Amin wrote:
> Hello,
> 
>    I have a question regarding schemes, versioning and references.  The 
> following is a simplified version of a real use case that we have.
> 
>    Suppose we have a QuestionScheme qs, which has 3 questions qA, qB, 
> qC.  At the beginning (wave1 for example), we have
> 
> qs v1.0.0
> 	qA v1.0.0
> 	qB v1.0.0
> 	qC v1.0.0
> 
> At this point in time, its clear that any QuestionConstructs or 
> Variables that reference these questions would use
> urn:ddi:agency:QuestionScheme.qs.1.0.0:QuestionItem.qA.1.0.0
>   or something similar (I might not have the exact syntax correct).
> 
> Now, my question comes up when we move to wave 2.  Suppose qA and qB 
> remain the same, but we change qC.  Now, we have
> 
> qs v2.0.0
> 	qA v1.0.0
> 	qB v1.0.0
> 	qC v2.0.0
> 
> Now, a reference to qA would be
> urn:ddi:agency:QuestionScheme.qs.2.0.0:QuestionItem.qA.1.0.0
>    Even though the question has not changed, we have a different version 
> for the QuestionScheme, and therefore a different identifier for the 
> QuestionItem.  If we have two different variables for the 2 different 
> waves, they would have different QuestionItemReferences, and therefore 
> it becomes impossible to determine that they are based on the same question.
> 
>    Is my understanding of this correct?  If so, doesn't this hurt the 
> reusability of items?
>    Thank you for your help.
> 
> Best,
> Alerk
> 


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