In my experience, the line between Dev. and DBA isn't always clear. In the absence of a true DBA, guess who ends up being expected to enforce Database best practices? Thats right, the Dev. is expected to know everything a DBA would be expected to know.
A few years back, the only thing I knew about databases was 3rd normal form, Primary Keys, Foreign Keys......that about sums it up. I don't think I'm far off by assuming that most devs know about the same. In the recent years though I've been fortunate enough to be throw at some more DBA type assignments and was able to learn more of the DBA roles' responsibilities.
In my more recent development projects, I find more and more that I'm asked, or expected to know more advanced database concepts. Things like indexes, database integrity checking, truncating large log files, etc.
Luckily, SQL 2005 makes these more DBA tasks pretty easy to perform by way of a Database Maintenance Plan. You can create a nightly job that will check your databases, shrink your logs, rebuild your indexes and backup your databases. These simple tasks will help keep your databases performing optimally in addition to making you appear to know more about databases.
Bill Baer has put out a great MS white paper about Database Maintenance pertaining specifically to SharePoint. It walks you through the steps that you should be doing to keep your SharePoint databases running at their best.
SharePoint aside, the white paper is just a good reference document about what you should be doing in general for your production databases, so I encourage any developer to read it.
Check out the white paper here.