What's best way to secure a database connection string?

Question

I am writing a set of database-driven applications in PHP. These applications will run on a Linux server as its own user. Other users will likely be on the system at times

Answer 1

My best solution so far has been to store config files in an encrypted partition so that people with direct access to the machine can't pull the passwords off by connecting the drive to another PC, and with file system permissions so people can't read the file from inside the OS itself.

You need to understand, though, that there's not much you can do against an attacker with direct access to the machine. If it's running the database server itself, then securing the config files won't have much effect if he can modify the database itself. Just make sure that everything is as secure as it can be and you'll probably be okay.