It shouldn't be possible to link multiple productseries to a sourcepackage in a given distroseries

This is the underlying cause of bug #352374. I think we can fix that bug by deleting the bad link. But it would be better if this non-sense never happened.

There are 81 bad packages in staging. I think we can clean fix this constraint, then fix the bad package

select
    distroseries.name as distroseries,
    sourcepackagename.name as sourcepackagename,
    count(sourcepackagename.name)
from
    packaging, sourcepackagename, distroseries
where
    packaging.sourcepackagename = sourcepackagename.id
    and packaging.distroseries = distroseries.id
group by
    distroseries.name, sourcepackagename.name
having count(sourcepackagename.name) > 1
order by
    distroseries.name, sourcepackagename.name;

The <productseries>/+packaging link allows the user to select any distroseries and any legitimate sourcepackagename regardless of if distroseries already has that package linked.

Once the mistakes is made, any attempt to fix the problem via the UI will cause an oops (bug #352374)
    Retry: duplicate key value violates unique constraint "packaging_uniqueness"

While it is possible to transfer the bad package to another project and series without packaging it cannot be deleted (bug #193469)

Trying to correct this from +addpackaging by leaving an empty sourcepackagename causes an oops (bug #344376) because
the form is not smart enough to know it is required

The user may create multiple packages for different productseries in the same distroseries, which causes two idential packages to be listed in the project page (bug #379017)

Fixed in db-devel r8667

Fixed released in launchpad-project 3.1.11.