If I was building an app for a conventional website, I'd opt for Python (probably with Django), though if you are just getting started and have a simple application, PHP is probably the easier path.
I went to the bookstore today to get the book you are reading but it is not available. So I have to quote my WROX reference:
var db = window.openDatabase(dbName, versionNum, displayName, maxSize);
What he glosses over is any detail about the database. I'm guessing that the answer lies with SQLite as there is no information about the way to connect. He describes it as being hosted 'locally'. Does that mean on the iPhone or iPad?
I Googled: 'sqlite on an iphone'. One really useful links is this one:
But there were several others that looked hopeful. I suggest that you start there.
But if you are looking for some serious database grunt, take another look at PostgreSQL with a little PHP to drive it!
Hope this helps!
Schrödinger's Cat has/had a split personality.