Well, the first thing you need to get with your new-to-develop application started is to gather some sample data. For the development-process creating this data by hand comes in handy, because you know excatly what data is available and what you should expect when querying your database.
But when it comes to testing your application in a real life environment you most likely need some more data. Last but not least you need to test performance and how your app scales. In this case you want to generate a lot of data. But generating this data can be tedious.
To work around this problem you need to have some kind of generator to create the data for you. While searching for such a tool I stumbled across this little tool from Microsoft call DBGen. It’s a little old-fashioned, but seems to do the job quite well.