Comment 1 for bug 627957

So I started the schema change as above yesterday, (adding source_pub/parent_source_pub), but soon realised that I don't think we want that amount of redundancy. We'd need to ensure at a DB level that both publications reference the same source package name, and that the publications are for the derived/parent distro series respectively etc. AFAIK, this could only be done with triggers like this:

http://pastebin.ubuntu.com/490866/

So unless I hear otherwise, I'll instead store source_version/parent_source_version so that we can remove blacklists for specific versions when they are updated (they will not be writeable outside of the DistroSeriesDifference model).