With the basic of Doctrine relations behind us, it's time to dive deeper and get our hands dirty with some real-world, but complex collections. Honestly, this is the hardest part of Doctrine: so let's get it right:
orphanRemovalto delete items in a collection
cascadeto save items in a collection
Doctrine relationships take a little bit more work to get setup. So let's master this stuff, setup our relationships to win, and get back to work.