What is the role of migrations in database change management?

Database migrations in database management are a way to systematically and sequentially make changes to the database structure (for example, adding tables, modifying columns, creating indexes) without data loss and with the ability to rollback.

They allow:

• Versioning the database schema, which simplifies team collaboration.
• Automating database updates during application deployment.
• Ensuring consistency of the database structure across different environments (development, testing, production).

An example of using migrations in Python with Alembic:

# Command to create a migration
alembic revision --autogenerate -m "Add email field to users table"

# Command to apply migrations
alembic upgrade head

Thus, migrations are a tool for safe and manageable changes to the database during application development and maintenance.