Comment 4 for bug 302253

A data fixing script is available to remove the newest and lowest status duplicate nominations: https://pastebin.canonical.com/11666/

However, bug 284950 had multiple nominations which had been approved, resulting in multiple bugtasks for the same productseries.

The script above returns the list of nominations it deletes (for example, <https://pastebin.canonical.com/11668/>) which can be used to figure out which bugtasks to delete.

I don't think there's an easy way to automate the removal of duplicate bugtasks because it's not safe to assume which one to remove. There has only been one instance of duplicate bugtasks so far, so this isn't so bad.

I've prepared some extra constraints for the BugNomination table, but some may also be needed for BugTask.