HowToCodePage

PostgreSQL

A feature-rich object-relational database.

💡
This course has 3 lessons. Start with the first one and use the next / previous links at the bottom of each lesson — the sidebar keeps the whole course in order.

Lessons

  1. psql and the basics of SQLDrive the server from psql, learn the meta-commands worth memorising, and create tables with the types PostgreSQL actually gives you.
  2. JSONB and arraysWhen a document column beats another table, how the JSON operators differ, and how to index both JSONB and arrays properly.
  3. Transactions and MVCC basicsIsolation levels in practice, why readers never block writers, and what vacuum is really cleaning up.

More in Databases

SQL MySQL MongoDB Redis SQLite

Last refreshed 2026-09-17.