A NoSQL database stores documents in collections without requiring every document to have the same structure. It stores the data present in each document rather than placeholders for data that is absent. section 8.5.1
This distinguishes it from a relational database, which organizes similarly structured data into linked tables. When assessing storage options, ask whether the data shares a consistent set of attributes or varies substantially from record to record. section 8.5.1
Documents in one collection
Two documents can differ radically while remaining in the same collection; neither needs empty placeholders for attributes found only in the other. section 8.5.1






