Database

A database stores data in tables made up of rows and columns, and provides a query language (usually SQL) to read and write that data. Unlike a spreadsheet, a database stays correct and fast even with millions of rows, many simultaneous users, and complex relationships between tables.

• —Virtually every app you use — social, banking, e-commerce — runs on a database behind the scenes.
• —Databases enforce structure (every row has the same columns), which keeps data trustworthy.
• —Knowing how to query a database directly is one of the highest-leverage skills for any builder.

This is the exact lesson that covers this term in depth — with examples, diagrams, and a hands-on exercise.