The application we'll be looking at (name changed to FRED to protect the innocent) is a well-known PHP content management system that has been in existence for over five years. No slights are intended against the developers of the code -- they created it with the intention of originally supporting MySQL alone. But that makes it a perfect candidate for our purposes. It reflects a common "V1.0" application development scenario resulting from the literal adoption of the LAMP stack. FRED is now morphing into a "commercial support available for a fee" software package that requires broader database support. FRED is running into the same problems that we will see as we walk through the code. ~Note~: I have an idea of how FRED's team is approaching some of these problems, and can share those with you along the way, but any approach requires trade-offs of some kind.