A tuts+ guide to MongoDB for people familiar with SQL and relational databases:
We will start with mapping the basic relational concepts like table, row,
column, etc and move to discuss indexing and joins. We will then look over
the SQL queries and discuss their corresponding MongoDB database queries.
By the end of it you’ll probably not be able to convert your app to MongoDB, but at the next meetup or hackaton you’ll have an idea of what those Mongo guys are talking about.
Original title and link: Mapping relational databases terms and SQL to MongoDB