MongoDB Fundamentals

MongoDB is an operational document database. A record is a document: field and value pairs that can contain nested documents and arrays. Collections hold documents, much as tables hold rows, but documents in one collection do not need an identical set of fields.

That flexibility is useful when an application works with hierarchical or variable data. It is not permission to skip design. Start from how the application reads and writes data. Data accessed together often belongs together. MongoDB can enforce selected rules with schema validation when a collection needs them.

The working model