Relational Databases
A database is the place where web applications store their information so it is not lost when turning off the server. Think of it as a spreadsheet, but much smarter, faster, and with the ability to relate different sheets to each other. This allows us to ask complex questions about the data very efficiently.
How to Design a Good Database
Now that we know what tables and relationships are, how do we decide how to organize information? This section teaches practical rules to build a well-structured database.
Exercises: From Text to Diagram
The best way to learn database design is by practicing going from a problem description to a diagram.
Entities in NestJS with TypeORM
Now that we know how to design a relational database (tables, relationships, foreign keys), it is time to implement it in code. TypeORM is the bridge between our NestJS code and PostgreSQL. This section shows how to translate entity-relationship diagrams into decorated TypeScript classes defining the system structure.
Weekly Slides
Official presentation slides for Week 3: Relational Databases, Clean Design Rules (Normalization), and NestJS Integration with TypeORM and PostgreSQL 18.