I'm new to MongoDB. Lets say I have a collection of blog post, and a collection of authors. I want to search for posts e.g. by topic, and language. But I only want results by certain authors, e.g. by age span. What's the correct way to do this? Should I search posts first, then iterate the result, and make a new search based on that? Or can I make a chained search somehow?
You may want to have a look on that document http://docs.mongodb.org/manual/reference/database-references/ . In general join is not a good practice for mongodb since it does not automatically supported. You might need to nest some author attributes - if not all information - that commonly used by your find queries on the blog collection for faster lookup.