I got a 7 year old boxer from a rehoming centre, and then a couple of months later a kitten. It was clear the dog wasn't used to living with a cat, she was very inquisitive and would go for cats when out on walks. But after finding out what happens when you corner a cat she seemed to stop that carry-on fairly quickly. I wouldn't be confident enough to leave the pair of them unattended in the same room but while I'm there with them they seem to behave.
Left alone I'd be afraid she might corner the cat and lose an eye. After all, dogs can be stupid and fail to learn. How can it be that such an intelligent creature be such a lug at times?