some UDD schema changes

[Lucas Nussbaum <lucas@lucas-nussbaum.net>]

Hi,

I've squashed a few items off my TODO list about UDD. I did the
following changes:

- 'release' columns are now ENUMs everywhere. This allows to compare two
  releases ('etch' < 'squeeze') or to order by release.

- all_packages_distrelcomparch (which was a hack) was replaced by two
  different tables (for Debian and Ubuntu) and a
all_packages_distrelcomparch view.

- lintian's tag_type column is now an ENUM as well. The order I chose
  is:
ENUM('experimental', 'overriden', 'pedantic', 'information', 'warning',
'error');
However, that's suboptimal, since experimental, overriden, and the
severities are orthogonal. But that's what is exported by lintian.log.
Is lintian.log really the best way to fetch information from
lintian.debian.org?

- Some indices proposed by Enrico were added.

It is worth noting that none of those changes require changes in your
queries (unless you relied on sorting releases or lintian tags
alphabetically, which doesn't sound like something you want to do).

However, turning release into an ENUM required changes in related tables
(packages and packages_summary), and the only way to sanely apply them
was to drop the table and create them again. Which I did, so the tables
are filling up again slowly, and will be completely filled in a few
hours.
-- 
| Lucas Nussbaum
| lucas@lucas-nussbaum.net   http://www.lucas-nussbaum.net/ |
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