Introduction

A database migration tool:

• Versions db schema
  • Safe, repeatable, ordered migrations
• Auto apply DB changes (Auto-run on app startup)
• Keep DB schema in sync with code

// like Git for your db schema

Without Flyway ❌:

• Everyone manually runs SQL scripts
• Different devs have different DB versions
• Production DB changes are risky
• Hard to rollback or track changes

How Flyway work:

1. SpringBoot app start
2. SpringBoot auto-detects Flyway if:
   • flyway-core dependency exists
   • A DataSource is configured
3. Flyway starts migrates DB before hibernate.
4. Flyway uses Spring’s DataSource to connect target DB.
5. Check flyway_schema_history table.
   • If not existed: auto-create it.
   • Existed: reads migration history.