Effective XML & why not to use XML as a relational database

A few weeks ago I had posted about 'complexity' and the XML banyan tree. It was from an experience with a tech team lead, who demanded on using an XML tree as a database. Sure enough, that little project was an exercise in futility (read the footnote on the prior posting for a possible solution). I received 'Effective XML' a few days ago and here is an interesting excerpt (pg 230) -

“XML is not a database. It was never meant to be a database. It is never going to be a database. Relational databases are proven technology with more than 20 years of implementation experience. They are solid, stable, useful products. They are not going away. XML is a very useful technology for moving data between different databases or between databases and other programs. However, it is not itself a database. Don't use it like one.“

A great little book with some great insightful gems - I wish I had this book a few months ago.. :-)