MongoDB - Associate Developer Study Guide

1: MongoDB Overview and the Document Model

This chapter establishes the foundation for building applications on MongoDB by covering the document model, the BSON type system, the role of `_id` and `ObjectId`, flexible schemas, the 16 MB per-document size cap, and the database/collection/document/field hierarchy. Every later chapter on CRUD, indexes, aggregation, data modeling, tools, and drivers builds on the semantics fixed here.