I completely disagree with Sunny. Do not keep your dog outside! As the days become years, many outside dogs sit, lay, eat, and defecate within the same 10-foot radius. They exist without respect, love, exercise, social interaction, and sometimes even basic nourishment. They live as prisoners, yet long to be pets.
Chaining is not only inhumane for dogs, but has taken a severe toll on this nation’s children as well. In the period from October 2003 through August 2008, there were at least 234 children killed or seriously injured by chained dogs across the country. Chained dogs, unsocialized with humans, can become very territorial of their tiny space, and any two year old who wanders into this space can be attacked and killed before adults can intervene. A recent attack in Texas in March, 2007 left 2 year old Carolina Sotello dead from head and neck wounds. She was attacked and killed by an unneutered male dog chained in the backyard, next to an unspayed female with puppies.
Potty training is hard...but if you follow the other fabulous advice you should have no problems. Dogs teach children about compassion and responsibility. What a rewarding lesson for your little ones!
Good luck!