Lectures

In this article, you'll find out what foreign keys are in relational databases, why you need them, how to use them to link tables and keep your data consistent, plus you'll see examples of different types of relationships and the syntax for creating foreign keys in PostgreSQL.

Learn how to create foreign keys in PostgreSQL, why you need them, and how to use them right to keep your data solid and organize relationships between tables. Examples, syntax, practical tips, and common mistakes — all in one lecture!

Learn how to manage relationships between tables in relational databases using cascade operations and constraints. We'll break down, with examples, how to automate deleting related data and protect data integrity when making changes.

Learn how to set up one of the most common relationships in relational databases — one to many ( ONE-TO-MANY). Using customers and orders as an example, we’ll break down creating tables, adding foreign keys, inserting and selecting data, plus typical mistakes and how to dodge them.

Learn how to properly implement a "many-to-many" relationship in relational databases using a join table. Examples of creating tables, inserting data, and running SQL queries for managing these relationships like a pro.