Modern Spring Boot applications rarely remain simple for long. A project may begin with a few entities and a handful of tables, but as it evolves, database schemas change continuously: columns are added, indexes are introduced, constraints change, new tables appear, and sometimes data itself needs to be transformed. The challenge isn't creating these changes. The challenge is making sure the same changes are applied consistently across every environment . This is where Flyway comes in. Flyway provides a versioned, repeatable mechanism for evolving a relational database schema alongside application code. When integrated with Spring Boot, it allows database changes to become part of the application's lifecycle and, eventually, the CI/CD deployment pipeline. In this article, we'll explore Flyway from the ground up and build a Spring Boot + PostgreSQL setup using migrations. 1. The Problem: Database Schema Changes Imagine a Spring Boot application initially has: users projec...