Schema vs model vs document in Mongoose?

Definition:

A Mongoose schema defines document fields and behavior, and compiling it creates a model used for collection operations. A document is one hydrated record returned or created through that model. Hydration supplies methods and change tracking, which are useful for edits but add work compared with plain objects.

Key points:

• Schema: field definitions, validation and other behavior.

• Model: the interface used to query a collection.

• Document: one hydrated record with Mongoose methods and change tracking.

• Database validation and application schema validation are separate layers; writes from another client may bypass Mongoose entirely.

Interview point:

• Distinguish the blueprint, the query interface and the individual record.