What are the changes to Drupal 7 programming vs Drupal 6?

Drupal 7 is 开发者_如何转开发claimed to be a revolutionary new Drupal. But in what ways exactly? Looking for coding specific discussions.. Thanks!

The Drupal core improvements handbook page includes an exhaustive list of improvements. Some of the highlights include a new database layer, RDF (Resource Description Framework) features, and fields in core. There's also an updated version of jQuery, the addition of jQuery UI, and Simpletest in core.

On a more granular level, specific API changes are documented on the Converting 6.x modules to 7.x handbook page.

Where did you read the word "revolutionary"? Every major version of Drupal contains many improvements. The Drupal community has chosen to not provide backwards compatibility, thus allowing faster and bigger changes with less overhead and performance loss. That means programming for Drupal 7 is indeed different, especially (like Matt V. says) when it comes to the new database layer, fields in core and entities. However, I wouldn't call it revolutionary.