My baby started to sleep all the night since born, though I need to feed him twice and change the diaper once during his sleeping period.
The way to training a baby to sleep all the night is to feed him or her regularly, and give him or her some indicts of the difference of the day and the night. For example, I feed my baby every 3 hours. If he is sleeping when he needs to eat, I will feed him anyway. For the indicts of the difference of the day and the night, I have him bathed in the water before he goes to bed, and I have him bathes in the sunshine after he gets up. And I never wake him up or turned the light on when I feed him and change him during the night.