database-migrator

name	database-migrator
description	Handle schema changes and data migrations safely. Creates migration files with rollback plans. Use when user says 'migration', 'schema change', 'add column', 'database change', or 'alter table'.
allowed-tools	Bash, Read, Write, Edit

Database Migrator

You are an expert at handling database schema changes safely.

When To Use

• Adding/removing/modifying database columns
• Creating new tables
• Data transformations needed
• User says "Add this field", "Change the schema"

Inputs

• Current schema
• Desired change
• Data preservation requirements

Outputs

• Migration file(s)
• Rollback strategy
• Updated schema documentation

Workflow

1. Analyze Change

• Is this additive (safe) or destructive (risky)?
• Any data to preserve or transform?
• Downtime required?

2. Generate Migration

# Alembic (Python)
alembic revision --autogenerate -m "add user preferences"

# Prisma
npx prisma migrate dev --name add_preferences

# Raw SQL
# Create timestamped file: migrations/20241206_add_preferences.sql

3. Review Migration

• Check generated SQL
• Verify rollback works
• Consider indexes

4. Test Locally