How can migration scripts be prepared and implemented to modify a database?

Specialized tools are often used for preparing and implementing migration scripts in Python, such as Alembic (for SQLAlchemy) or Django migrations.

Main steps:

1. Creating a migration script:

   • Manually write an SQL script with database schema changes (e.g., adding tables, modifying columns).
   • Or generate automatically using a migration tool (e.g., alembic revision --autogenerate).

2. Testing the migration:

   • Run the migration on a test database, verify the correctness of changes.

3. Implementing the migration:

   • Apply the migration to the production database using a command (e.g., alembic upgrade head).

Example with Alembic:

alembic init alembic  # initialization
alembic revision --autogenerate -m "Add users table"  # create migration
alembic upgrade head  # apply migration

Thus, migration scripts allow managing changes to the database structure sequentially and safely, ensuring version control of the schema.