Jens Schauder has an interesting suggestion about the development environment for your projects - one database per developer.

How many databases run in your teams development environment? One for the complete team? I have seen many places like that, but please tell me: Why? You aren’t working on a shared files system aren’t you? How is a developer supposed to change the structure of that database without interrupting the work of the other developers? And just in case you haven’t noticed: Pretty much every RDBMS vendor offers free versions of their database which can run on a developer machine.

He suggests that every developer needs their own isolated database instance where they can run rampant through the data and only cause any real issues (or correct major ones) without having to worry about the impact on others. Keeping them in sync is a whole different story, but can be helped with something like fixture data.