Enter into psql terminal: Create a new test database Create a users Table Check the db and table details Add a Primary key to users and check the user table. You can a unique constraint and an index added when adding a primary key. Why does adding a primary key also add an index? A … Continue reading Rails 8 App: Setup Test DB | Comprehensive Guide 📖 for PostgreSQL , Mysql Indexing – PostgreSQL Heap ⛰ vs Mysql InnoDB B-Tree 🌿