When i change doctype names and field names , new doctype(new tables) and new fields are created.
The older doctypes,tables are there. The older fields(columns) are there when i change field names.
I deleted old doctyes, dropped old columns from mysql. deleted folders in doctype folder.
after that updated the app in production.
But the columns and doctypes are still present in production. so i removed them in the same way.
I didn't find the right solution from the Internet.