What is it
MongoDB is a document-oriented NoSQL database that stores data as flexible, JSON-like documents rather than rows in fixed tables, allowing schemas to vary between documents in the same collection.
Why it matters
MongoDB represents a genuinely different approach to data storage than relational databases, and understanding when a flexible, document-based model fits a problem better than a rigid relational schema is an essential skill as applications increasingly mix both paradigms.
Exam tip
Resist the urge to design a MongoDB schema exactly like a relational one split into many small collections — MongoDB's strength comes from embedding related data together within a single document where appropriate, and over-normalising defeats much of its purpose.
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