Database engineering

Relational databases in depth with PostgreSQL: SQL, modelling and normalisation, indexes and query plans, transactions, isolation and locks, operations, and typing database code.

3 lessons
2 h to read and try
Before this: Backend engineering

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When you finish, you can

Write SQL for any everyday query, including joins and aggregates
Model data in tables, normalise it, and denormalise on purpose
Read a query plan and add the index that fixes it
Choose an isolation level and prevent lost updates and deadlocks
Plan migrations, connection pools and backups
Type rows, entities and DTOs without confusing them

You build: A normalised, indexed schema for a shop, with migrations and typed repositories

MODULE 1

SQL

1How databases workWhy a backend keeps its data in a database, how relational databases organise it into tables and relationships, and what keys, constraints, indexes, transactions and migrations do, with real PostgreSQL running inside Node.js.45 min
2SQL with PostgreSQLInstall PostgreSQL with an installer or with Docker, talk to it with psql, and learn the SQL every backend uses: create, insert, select, update and delete, with filters, sorting and paging, and parameterized queries that stop SQL injection.45 min
3Joins, grouping and transactionsCombine tables with joins, summarise data with group by and aggregates, filter groups with having, nest queries, control transactions yourself, measure queries with explain analyze, and connect Node.js to a real PostgreSQL server.45 min

Course checkpoint

Prove you can move on. The checkpoint picks 15 questions at random from every lesson in this course. Get 12 right to pass. Your result is saved in this browser only.