juniorNoSQL
Explain the CAP Theorem.
Updated Apr 28, 2026
Short answer
The CAP theorem states that a distributed data store can only provide two of three guarantees: Consistency, Availability, and Partition Tolerance.
Deep explanation
Junior level NoSQL understanding focuses on the move away from rigid relational constraints. In NoSQL, data is often denormalized for speed. For instance, in a document store like MongoDB, instead of joining multiple tables, you might embed related data directly into a single document to reduce read latency.
Real-world example
Using Redis (Key-Value) to store session tokens for a high-traffic web application for sub-millisecond retrieval.
Common mistakes
- Treating a NoSQL database exactly like a relational one by normalizing every piece of data.
Follow-up questions
- When should you NOT use NoSQL?
- What is Eventual Consistency?