Great Dane are not ideal dogs for apartment dwellers. They do need space. Moreover, dogs are highly social able animals. They do need company of humans or their fellow mates all the time. It's not a very nice idea to keep the dog locked inside the house while you are at work. Moreover, puppies need to be properly house-trained so that they are trained where they should do their daily business - relieving. This house training can last from the day you bring the puppy in to any time from a month to even a year depending on how well and quickly the puppy picks up the training. The training is an ongoing process. I'm not sure if a person who stays along and works 9 to 6:00 can make such training environment conducive.