Database Migration
==================

We currently use **Alembic** to handle database versioning. 
All files related to migrations are located into *src/bmapi/alembic*.
All revisions are located into the *versions* folder.
We will go through the step to create a migration and also update your database to the latest revision.

Create a new migration
----------------------

    Note that your **BRAUMEISTER_DB** environment variable must be set to proceed.
    Also make sure that the database is currently running.

You can create a migration by running *alembic revision* and you can also specify --autogenerate.
That way, alembic will generate the migration code for you but it doesn't add code for data migration, only the schema.
Review that revision after.

.. code-block:: console

    (venv) $ cd src/bmapi
    (venv) $ alembic revision --autogenerate -m "my revision name"


Update to latest revision
-------------------------

    Note that your **BRAUMEISTER_DB** environment variable must be set to proceed.
    Also make sure that the database is currently running.

You just need to run *alembic upgrade head* to apply all missing revisions to your database.

.. code-block:: console

    (venv) $ cd src/bmapi
    (venv) $ alembic upgrade head