DBMS

Storage and Queries

Before data can be analysed, it has to be stored somewhere. This section covers how databases work — the relational model, SQL, normalization, transactions, and indexing. The concepts here are foundational for structured data at any scale.

Indexes

intermediate

The thing that makes queries fast without changing any data.

Joins

beginner

How you stitch two tables together based on a shared column.

Normalization

intermediate

The art of organizing your tables so data doesn't contradict itself.

The Relational Model

beginner

Data lives in tables. Tables connect through keys. That's the whole idea.

SQL Basics

beginner

The language you use to ask a database a question.

Transactions and ACID

intermediate

How databases make sure your data doesn't end up in a half-written, broken state.