ecto-migration-helper

Ecto migrations require defining both up and down functions to enable safe rollbacks. This Skill automates migration generation with best-practice patterns for reversible schema changes, including proper handling of defaults, NOT NULL constraints, foreign keys, and composite indexes.

Data migrations in Ecto should use batched updates to avoid locking large tables and maintain reversibility. This Skill provides guidance on safe patterns for data transformations, ensuring your down function can undo changes and your application handles both old and new states during rollout.

Yes. Ecto migrations support adding and removing columns, indexes, and constraints, but some operations—like removing columns with data—are non-reversible. This Skill teaches which changes are safely reversible and how to structure migrations to maximize rollback compatibility.

Foreign keys and composite indexes require careful ordering and constraint definition to avoid conflicts and performance issues. This Skill provides recommended patterns for declaring foreign keys, building indexes safely, and ensuring migrations apply cleanly across environments.

Reversible migrations preserve data and schema state in both directions—your down function fully undoes the up function. Destructive operations like dropping columns or data loss are non-reversible. This Skill clarifies which operations support rollback and how to structure alternatives when rollback support is critical.