Databases, Explained
an interactive guide

Databases,
explained one step at a time.

Six short, click-through lessons on how databases keep data fast, correct, and in sync.

01

ACID Transactions

All-or-nothing changes, even when things go wrong.

start
02

Indexes (B-Trees)

Finding one row without scanning them all.

start
03

Joins

Combining rows from two tables into one result.

start
04

Primary & Foreign Keys

How tables stay linked — and honest.

start
05

Replication

Keeping copies of your data in sync.

start
06

Sharding

Splitting one big table across many machines.

start