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Document Database

A NoSQL database that stores data as flexible, self-describing documents (typically JSON or BSON), allowing varied structures within the same collection without requiring a predefined schema.

Document databases store records as documents, each containing its own structure. Unlike relational databases where every row in a table must conform to the same schema, documents in the same collection can have different fields. This flexibility accommodates evolving data models, semi-structured data, and hierarchical information that maps naturally to application objects.

MongoDB, CouchDB, and Amazon DocumentDB are popular document databases. They excel at use cases with rapidly evolving schemas, hierarchical data (user profiles with nested preferences), and applications where each record may have different attributes (product catalogs with varying specifications per category).

For AI teams, document databases are often used to store unstructured or semi-structured data that feeds ML pipelines: user interaction logs with varying event schemas, content metadata with flexible attributes, and model configuration documents. The schemaless nature allows data structures to evolve alongside model requirements without migration overhead. However, the lack of enforced schema can lead to data quality issues if governance is not maintained.

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