What does it mean that Azure Cosmos DB is multi-model?

Question

Looking at the new Azure cosmos database, I\'m a bit confused about the multi-model nature of it. Specifically, does it mean:

a) That the same underlying database/store

Answer 1

I too was intrigued by this, wanting to understand more from a API usage auditing perspective and have learned more reading through these answers.

Upon experimenting it appear things have progressed further than the original answers, so to add a contemporary spin...

I have been able to successfully create a Cosmos DB account choosing the SQL API, created a document in the portal then retrieved the document via the MongoDB API.

The original answers suggested that MongoDB was the odd-one-out and couldn't interact with data created with other APIs.

Now whether with fuller testing this would result in corrupt documents due to the data type differences hinted upon by Yaron (https://stackoverflow.com/a/48286729/141022) and whether the storage differences would result in poor performance still as hints to that is to be seen.

For my purposes I'm interested to whether auditing one API is enough, which in this case it is not as data created in one can be retrieved by another, so I haven't tested in depth.

Notably, the ARM template deploys with neither GlobalDocumentDB nor MongoDB kind, however exporting the ARM template back from the portal results in GlobalDocumentDB if that happens to make a difference.