I lost DB.php, Where do I find it?

I was helping a colleague get a website back online after a server meltdown.  The database was not connecting and the page was complaining about a missing file:  DB.php.  I checked the backup and the files were not there.

Of course the first thing that came to mind is how did this website ever work if it needs that file...?

After some Googling and testing I found that  I needed to install the DB model from the PEAR Repo.

pear install DB

I ran that as root and I was in business.