yesodweb/persistent — pull request #106 by meteficha (2012-12-13 21:16:18+00:00)
Title: Allow NULLables on uniqueness constraints.

They're supported by the SQL standard and are useful.

Also includes some misc fixes. I'm going through the pull request flow since I'd like someone to review these commits =). I've ran the tests against SQLite and MySQL, which is what I already have installed. It should work on PostgreSQL as well according to its docs. I don't have any idea wrt. mongoDB and CouchDB.