Dev_CodaLab CLI Database Migrations - sidaw/codalab-worksheets GitHub Wiki

Database migrations

Migrations are handled with Alembic.

If you are planning to add a migration, please check whether:

  • You have a fresh DB with no migrations, or
  • You have already done a migration and wish to add/upgrade to another.

By running this command:

venv/bin/alembic current

If you have a migration, it will show you your last migration (head). (In this case it's 341ee10697f1.)

INFO  [alembic.migration] Context impl SQLiteImpl.
INFO  [alembic.migration] Will assume non-transactional DDL.
Current revision for sqlite:////Users/Dave/.codalab/bundle.db: 531ace385q2 -> 341ee10697f1 (head), name of migration

If the DB has no migrations and is all set, the output will be:

INFO  [alembic.migration] Context impl SQLiteImpl.
INFO  [alembic.migration] Will assume non-transactional DDL.
Current revision for sqlite:////Users/Dave/.codalab/bundle.db: None
You have a fresh DB with no migrations.

Simply stamp your current to head and add your migration:

venv/bin/alembic stamp head
You have already done a migration and wish to upgrade to another.
venv/bin/alembic upgrade head

[TODO write about edge cases]

Adding a new migration

  1. Make modifications to the database schema in tables.py.

  2. If necessary, update COLUMNS in the corresponding ORM objects (e.g., objects/worksheet.py).

  3. Add a migration:

     venv/bin/alembic revision -m "<your commit message here>" --autogenerate

This will handle most use cases but check the file it generates. If it is not correct please see the Alembic Docs for more information on the migration script.

  1. Upgrade to your migration (modifies the underlying database):

     venv/bin/alembic upgrade head