MongoDB Study Flashcards
Leading document-oriented NoSQL database managing schema-less JSON-like BSON objects. Click any card to flip and test your knowledge.
What is BSON in MongoDB?
Binary JSON (BSON) is the binary serialization format used to store documents and extend JSON with data types like Date and ObjectId.
What is an ObjectId?
A 12-byte unique identifier generated automatically for document _id fields containing timestamp, machine, process, and counter bits.
What is the Aggregation Pipeline?
A multi-stage framework ($match, $group, $lookup, $unwind) for transforming and summarizing documents sequentially.
How does $lookup work in MongoDB?
It performs an equality left outer join to a collection in the same database to pull in related document arrays.
What is a Replica Set in MongoDB?
A cluster of MongoDB servers maintaining identical data copies to ensure high availability and automatic failover.
What is Sharding in MongoDB?
Horizontal scaling method partitioning document datasets across multiple server shards using a shard key.
What is a 2dsphere Index?
An index supporting spatial queries over spherical geometry objects like points, lines, and polygons.
What is Schema Validation in MongoDB?
JSON Schema rules enforced during write operations to guarantee document structure integrity.
What does the $unwind stage do?
It deconstructs an array field from input documents to output a document for each element in the array.
What is an Upsert in MongoDB?
An update operation that updates matching documents or creates a new document if no match is found.
Need practical SQL queries for MongoDB?
Explore our ready-to-use copy-paste query recipes in the Cookbook.