python - After the 5.11 operation in the Flask Web Development book, only the database was migrated. Why was the database data not migrated?

Question

Only the database was migrated, but the contents of the database were not migrated.

習慣沉默 · Answer

I think you don’t understand the meaning of migration!
Migration probably means adding or subtracting tables from the database, which means modifying tables, deleting tables, and renaming tables!