Developers familiar with relational databases and SQL but interested in moving into the NoSQL world - MongoDB, in particular - might find this recent article from Ashish Trivedi at Tuts+ to be helpful. It explores the structure and use of MongoDB in terms of relational databases, making comparisons and pointing out similarities in order to draw on existing RDBMS knowledge. For example, Trivedi makes the following connections:
- RDBMS tables map to MongoDB collections
- RDBMS rows map to MongoDB documents
- RDBMS columns map to MongoDB fields
- RDBMS relationships map to linking and embedding documents in MongoDB
Trivedi goes on to compare SQL queries to MongoDB queries, presenting code samples of things like SELECT and UPDATE statements side-by-side with their MongoDB equivalents. Overall, it's a relatively basic look at both SQL and MongoDB - mostly a way to get started with something entirely new - but well-organized and very helpful in its reliance upon more common RDBMS knowledge to understand MongoDB. Check out the full article for more details.