> They are restrictions on the copyright owner.
What do you mean? Moral rights do not restrict the Moral Rights holder in any way, and they do restrict the ways that any other person is allowed to present, re-present, or modify the work.
Moral rights can only restrict copyright holders when the copyrights have been transferred from the creator of the work to another party, and in that case, Moral Rights restrict all people who didn't author/create the work equally, it has nothing to do with who holds the copyrights.
> It [US copyright law] specifically mentions that it [database copyrights] doesn't exist.
You have a good point! I was at least partially, if not completely incorrect. :)
But, it would still be a bad idea to assume you have the right to copy someone's database. It might not be a violation of copyright law, but there's a good chance it is a violation of some law. The sui generis database rights link happens to give a separate reason for why it would be a bad idea to copy someone's database. :)
I also just had to check... ;) The text of US copyright law does mention databases twice. http://www.copyright.gov/title17/circ92.pdf It specifically mentions, in definitions, that databases are not works of visual art, and that databases are not considered a "digital audio recording medium". It does not seem to specifically exclude databases categorically, but considering the language in the 'sui generis' article you linked, "Uncreative collections of facts are outside of Congressional authority". The keyword is 'creative', and if a database were shown to be the primary form of a "creative" work, copyright law may apply.