flask (python web app framework)

1. db migration error

ref: alembic tutorial

problem：

raise util.CommandError(“No such revision ‘%s’” % id_)

alembic.util.CommandError: No such revision ‘38c4e85512a9’

solution：

1. rm migration directory in your app

2. create migration script, such as migrations/versions/3ade73be6c40_initial_migration.py

python manage.py db revision -m “initial migration”

3. specify head(now your head should be 3ade73be6c40)

python manage.py db stamp 3ade73be6c40

4. upgrade your db based on new defined models.py

python manage.py db upgrade

when you finish, next time you change your db,

1. python manage.py db revision -m “your-comment”

vim migrations/versions/xxxxxxx_your-comment.py 修改遷移腳本

1’. python manage.py db migrate -m “your-comment”

檢查遷移腳本

2. python manage.py db upgrade

2.