[#12048] Data migration: ensure consistency when script is stopped and resumed

[yuanxi1]

Part of #12048

Outline of Solution

• Using the cursor saving mechanism from base sql script as checkpoints
  1. Cursor position is saved after successfully migrating a course entity
  2. Cursor position is loaded when first start up the script, and the course entity A it points to if is not marked as migrated, a casecadeDelete method will be called to delete all related entities in the sql database and migration will restart from A.

Edit:
CascadeType.REMOVE is already present for most parts of the chain but not present for Course-FeedbackSession, Course-User. For easier implementation for deleteCourseCascade, added cascade = CascadeType.REMOVE annotation for the two relations in Course.java.

[FergusMok]

Great, looks good to me, just very tiny nits

[NicolasCwy]

Nice work on getting this out, some changes are required though

[NicolasCwy]

I think this is a one-liner, could we do this in this PR?

[yuanxi1]

I don't think calling HibernateUtil.remove(course) can cascade delete other entities, maybe need to do something like in CourseLogic

[NicolasCwy]

I think you're right, I was originally thinking of using Cascade on delete annotation but there may be performance issues with this

[FergusMok]

I think performance issues should be fine because deleting is expected to only happen rarely (error in validation, exception thrown, or halfway migrated)

[NicolasCwy]

LGTM thank you for your work on this!

[FergusMok]

Great work, especially on the more detailed parts of the logging and the cascade on users