We have a very benevolent cat, bless his heart. Mia attacks him all the time and he never shows his claws. Sometimes he chases her back, sometimes they play very well together, but other times Mia is just being aggressive. I would suggest starting obedience training with your dog as soon as possible. Dogs respond to training even when they are around 8 weeks old.
Currently Mia and I are working on "leave it."
Actually I was complaining about Mia's behavior and some members posted very helpful info. Let me try to find that thread.
Okay, here it is:
http://www.yorkietalk.com/forums/sho...ighlight=leave
Good luck.