DDR Data Science Interview Practice Test

MongoDB is a document-oriented NoSQL database that stores data as flexible JSON-like BSON documents. This means you model data as documents inside collections rather than rows in fixed tables, and each document can have its own structure, with nested fields and arrays, giving you a dynamic schema. Because it’s a document store, you can query on document fields with a rich query language and benefit from features like indexing, replication, and sharding for scalability. The other descriptions don’t fit: relational databases use tables with fixed schemas, key-value stores are mainly for simple value lookup (often caching), and graph databases specialize in traversals over nodes and edges.