7.26. Migration About

7.26.1. Migration Software

  • Alembic

  • Django Migrations

  • Yoyo Database Migrations

  • Migrate

  • SOLAlchemy Migrate

  • SQL Migration Runner

  • Liquid Base

  • FlywayDB

7.26.2. Lifecycle

  • Create Migration

  • Run Forward (apply)

  • Run Backward (rollback)

7.26.3. Alembic

  • Heavily relays on reflection

[alembic] # path to migration scripts script_location = h:migrations # Edit the engine string for production sqlalchemy.url: postgresql://hypothesis-h-prod-db.us-west-1.rds.amazonaws.com :5432/h

Create:

$ alembic revision -m "create organization table"
Generating h/migrations/versions/1975ea83b712_create_organization_table.py...done

Run forward:

$ alembic upgrade head
INFO [alembic.context] Running upgrade None -> 1975ea836712

7.26.4. Use Cases

  • Create Table

  • Alter Table

  • Add Column

  • Drop Column

  • Rename Column

  • Modify Data