Which are the most noteable things which make working with Core Data different than with MySQL?

One thing I have in mind is, that datasets in Core Data (or lets say: managed objects) have no ID like known from other database开发者_如何学Gos such as MySQL. Also, they're not in a specific guaranteed order.

What else makes Core Data much more "special" compared to working with a relational database like MySQL? Besides the whole object graph persisting and ORM stuff?

This is a good article explaining the main differences. The biggy for me is

'Core Data cannot operate on data without loading the data into memory'

This alone makes core-data and MySQL suited to totally different tasks.

The big difference I would say is that Core Data is built on an ORM, an Object Relational Mapping, while MySQL is just a relational database. You could actually host CoreData on MySQL if Apple wanted to let you. Instead they use a different embedded SQLight solution or an XML representation depending on what you want for your backing store.