Recorded at the Dutch PHP Conference, this session covers advanced object-oriented design patterns in PHP. This was a very popular talk with excellent reviews, delivered by Tobias Schlitt from Qafoo...

Stephen - it is a shame that we don't seem to have the debugging features in MySQL that Oracle has; they are invaluable. Developing and debugging stored routines is something I want to look into further as I think they have the potential to be very valuable in an enterprise environment and I don't want to give up on them.

Stephan - As you say this is intended to be an introductory article and the book you suggest sounds ideal for jumping in deeper to explore performance/optimization. I intend to get hold of a copy.

- Always use the latest stable version that is available for your platform

- Watch the column types, to use the smallest type that meets your needs

- Normalize your data as much as possible to meet usage requirements

- InnoDB is the default database storage engine from 5.5 (I think) and its performance is being improved countinously and is now at par with MyISAM. Infact in 5.6 its getting FullText Index support.

- Updating Related Records - use referential integrity and foreign key constraints. The addage also is that you do not want to keep the same data in different places, compute the data only when you have to. Also there are is a materialized view implementation which uses tables, but needs to be monitored if your database has lots of inserts and updates as it can bring your database to its knees

- MySQL views are slow especially when you start hitting over 1 million records per table for the different joins and the situation has not got any better

- MySQL Stored Procedures and functions are terrible to develop and debug, only needed when you have functionality which cannot be emulated in SQL, and the key is to stay away from them as far as possible. You can encapsulate the even driven functionality into the business tier using PHP even dispatcher classes like teh Event Dispatcher (http://components.symfony-project.org/event-dispatcher/)

I guess you can set the identityMap for the current saved customer, just like you have done in the "find" method.

// Store customer object in identity map
$this->identityMap->offsetSet($id, $customer);

Do you think that make sense?

In my example I created classes manually, but to my understanding Doctrine will work it out based on metadata.

How would ORM like doctrine 2.0 fit into your example?

I did notice a tiny error in your example though:

// And return Customer object
return $address;

Should probably be :

return $customer