How do I know if my schnauzer has diabetes?

Guinness &- Wallace

Barked: Thu Feb 5, '09 6:08pm PST 
I have a 10 month old mini schanuzer, Wallace. Wallace drinks more than my other schnauzer and needs to be let outside about every 2-3 hours. He eats like a goat. I bought him a buster cube to slow his eating, which has helped a bit. Does this sound like an onset on schnauzer diabetes?