Funny you should ask! I had 2 Danes when my children were very small. In fact, I believe with the first one my son was 18 months when we got him and I was still pregnant with my daughter. And with the second one, they must have been 5 or 6, in that age range. It's been a long time since they were young, lol.
Both dogs were very mild tempered and the children could do just about anything to them, but I was always cautious as you should always be with young children and dogs. But they were great dogs, and tolerated anything the kids did to them. They both loved the kids and played with them all the time. They are so big and goofy and are totally unaware of their own size, so it's pretty funny to watch them.
Just be sure you see a health certificate from the breeder. Danes have a lot of problems with their hips because of their size. They may be prone to bloat too, I would read up on that if I were you. I had never heard of bloat back then (30 years ago), so I can't tell you if they are one of the breeds that tend to have problems with it. I think they may be because of their size.
But they are great dogs, they really are. I had a black and a blue and the blue was absolutely gorgeous. Ohhhh, bringing back memories....