Database Refactors

Are you struggling with **database migration conflicts** during large-scale refactors? This video explores why legacy and refactor branches often represent incompatible views of the same database and why pointing them at the same development instance is a recipe for disaster. In this guide, we break down why migration tools fail when histories diverge—explaining that they track the **sequence of operations** and checksums rather than just the final schema shape. We also dive into why common "fixes" like `IF NOT EXISTS` can paper over dangerous schema drift. **What you will learn:** * **The Isolation Model:** How to host multiple independent databases on a single local MySQL server to keep your development environment predictable. * **Step-by-Step Setup:** A walkthrough of creating branch-specific databases, granting privileges, and managing environment variables safely. * **The Safe Branch-Switching Routine:** A deliberate workflow for stopping applications and using specific Docker flags (`--no-deps`, `--force-recreate`) to ensure environment variables are correctly reloaded. * **Verification & Recovery:** How to triple-check that your Git branch, environment variables, and migration logs agree before running any commands, and how to recover if a cross-branch migration occurs. * **Converging for Release:** Strategies for merging your refactor, including choosing a canonical history and running **clean-install vs. upgrade tests** to catch different failure classes. **Key Strategy:** Isolate divergent histories during development, then converge them deliberately before you ever hit production. Stop fighting your migration history and start **isolating your databases** for a smoother, safer refactoring experience.