database-migration-helper_skill

Overview

This skill creates safe, reversible database migrations across multiple ORMs and raw SQL. It generates schema changes, data migrations, indexes, constraints, and rollback steps with attention to transactional safety and production-ready practices. Use it to produce migration files, data transformation scripts, and a clear rollback plan.

How this skill works

The skill inspects the requested schema change and target ORM (Prisma, TypeORM, Alembic, Sequelize, raw SQL) and emits an up and down migration with appropriate types, enums, and indices. It includes optional data migration steps, transactional wrapping, and notes about performance (batching, indexing after bulk writes). It produces concise migration code, commands to run or revert, and a short checklist for testing and deployment.

When to use it

• Adding or removing tables, columns, enums, or indexes
• Refactoring schemas (splitting/renaming tables or columns)
• Creating complex data transformations or migrating JSON structures
• Preparing safe rollbacks before production deploys
• Converting ORM model changes into executable migrations

Best practices

• Always provide both up and down implementations and document destructive steps
• Run migrations on a copy of production data and validate results before deploy
• Use transactions and batching for large data migrations to avoid long locks
• Create or rebuild indexes after bulk inserts for faster writes
• Version-control all migration files and never edit deployed migrations
• Include short comments explaining non-obvious transformation logic

Example use cases

• Add a role enum and role column for users with index and default value, plus data backfill for existing rows
• Rename a column by creating a new column, migrating data, then dropping the old column with safe rollback
• Migrate relational rows into a JSONB profile field with transformation and integrity validation
• Create a new table schema, migrate existing data into it, drop the old table, and rename the new table
• Generate ORM-specific migrations (Prisma schema change, TypeORM migration class, Alembic revision, Sequelize file, or raw SQL up/down scripts)