Wolfram Language version 11.3 now has support for interfacing with MongoDB: http://reference.wolfram.com/language/MongoLink/guide/MongoLinkOperations.htmlsupport for interfacing with MongoDB.
You can connect to a MongoDB database via MongoConnect. For example, connecting to a database running locally:
In[1]:= Needs["MongoLink`"] client = MongoConnect[]; MongoGetDatabaseNames[client] Out[2]= {"Test", "admin"}