SQL, NoSQL, and NewSQL Databases in System Design

Compare database choices using data shape, query patterns, transaction scope, consistency settings, and operational limits. SQL and NoSQL are broad labels; the important question is whether a specific product and configuration support the workload’s required behavior.

List the operations the database must support before choosing a product. Include the largest expected queries, the writes that must be atomic, and the data that may be temporarily stale.

This choice fundamentally shapes an application’s ability to scale, maintain data integrity, and perform under load. With many options out there, selecting the right one can feel daunting, but a wrong decision can lead to costly rewrites and performance bottlenecks.

In a System Design interview, success often depends on explaining why a specific database choice fits the system’s needs.

This lesson offers a practical guide to understanding databases. We will explore the core architectures, ranging from traditional SQL to modern NoSQL and NewSQL systems, which will help us understand their respective strengths, weaknesses, and ideal use cases.

Introduction to Database Systems

A database is an organized collection of data, structured to be easily accessed, managed, and updated.