I am not aware of any working project...this answer is based on a short analysis I made few years ago.
NoSQL databases (MongoDB, CouchDB, Cassandra, Ignite, Hadoop, Hbase, and so on ...) are very specific to themselves, almost nothing to share with (R)DBMS we are used to. You should not expect a standard Uniface driver available to access data stored because data access is often VERY specific for each one of them.
Into Community samples there is available a nice example for CouchDB from Eddy Knocks but I do not think it could be reapplied to MongoDB because CouchDB could be used through a RESTful API giving back JSON streams while MongoDB has its own specific query language.
Nevertheless an ODBC driver should be available for MongoDB and you could experiment with it; it should be possible to send a query to MongoDB using this driver together with Uniface ODBC wrapper and "sql" Proc Script instruction.
If you will decide to proceed:
- first thing first: GOOD LUCK! 🙂
- second: prepare yourself to write (a lot of) code
- third: keep us updated on pro and cons of your experiments (thanks in advance!)