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alembic - Python migrations quick start

# a new column, model, etc. has been added before
alembic revision --autogenerate -m '<describe your changes>'

# review the migration in backend/feedback/alembic/versions

# upgrade to the latest version
alembic upgrade head

Make it a point to downgrade and upgrade whenever a change has a migration, to make sure nothing breaks.

Field length changes

Alembic doesn't detect field length changes by default, it's configuration has to be modified to detect it.

Setting up alembic to detect the column length change

Alembic - migration for String length change


Alembic can make errors when using context.configure(url=url, target_metadata=target_metadata, literal_binds=True, compare_type=True)

when using compare_type.