The quiz for the Schema Validation lecture has the following question:
Which of the following can be validated through schema validation in MongoDB?
One of the answers is:
A document has either one of two strict shapes.
There is a construct in JSON Schema called oneOf that let you specify two sub-schemas.
Use this technique for verifying different shapes of documents, including checking a specific shape for a document version.
Could someone please clarify why a document has either one of two strict shapes?