The OP's suggestions are pretty bad, as jasonkester points out. But for a specific class of problems (ones that are both performance or JOIN intensive and require the awesome indexing/sorting capabilities in SQL solutions), schema-less MySQL, when done "correctly" is awesome. I designed an application that needed to do graph traversal in real-time, so normalized SQL wasn't an option for me. I tried various NoSQL solutions, but they all either lacked important features or ran insanely slow. I ended up settling with a design similar to how FriendFeed uses MySQL: http://bret.appspot.com/entry/how-friendfeed-uses-mysql

Not only was the solution faster, but it made code so much more concise, because you can just serialize Python objects to the database rather than write a huge database abstraction layer. For me this is even more valuable than the performance ramifications.

If you're using Python+MySQL, be sure to check out Tornado's database wrapper (http://github.com/facebook/tornado/blob/master/tornado/datab...) because it handles all sorts of sharp corners that straight up MySQLdb won't (like working with binary data, reconnecting when necessary, etc.)