SQLite Was Right, Until It Was Not

SQLite was the correct choice for learning, and it is a genuinely excellent database. It is a file, it needs no server, and it ships on every phone. For a single-user application it is often still the right answer in production.

What it is not built for is many people writing at once, over a network, from several application servers.

What PostgreSQL gives you.

Concurrent writers, without the whole database locking.

A network connection, so several application servers share one database.

A much richer type system: real dates, arrays, JSONB, ranges, precise decimals for money.

Stronger constraints, including ones spanning several columns.

A query planner you can interrogate with real timings, not just an intention.

Extensions, including full text search and geographic data.

None of that is free. It is a service to run, back up, connect to and secure.

✦ This course is honest about one limit

PostgreSQL is a server, and a server does not run in a browser tab. The graded editors here run SQLite, so every graded query is written in portable SQL that behaves identically on both. Where Postgres genuinely differs, that difference is the lesson, and you practice it against a real PostgreSQL in the project steps.