I have problems with the solution of the lab “Apply the Schema Versioning Pattern” in Chapter 4.
In my understanding, the “schema versioning pattern” is a solution strategy for the situation of having an existing document structure and need to replace (a subset of) this structure (e.g. one attribute) without having the need of stopping the application, migrate all data to the new structure and then starting a new version of the application to work (only) with the new structure.
So it is more than just having documents with different structures in the same collection and having an application that can handle those different structures. It is also more than adding just some attributes to an existing structure and change the application to handle those additional attributes, if they are present.
So in my opinion, only scenario B is “best suited” for the “schema versioning pattern”, because scenario A just adds attributes and scenario C just holds documents with different structures in one collection.
But my answer was marked as “wrong”.
Could anyone please tell me if I made an error in reasoning.
Thanks in advance