Do You Know How to Decouple a Data Base Access Object?

So i've got a d a o, for lack of a better word, a data base access object. Some some place in my code where im going to be able to say, get me all the people from theDataBase. And so it's like a facade between you and the data base. It's providing some logic in some way, on the some some reason for abstracting out those two different pieces. O, can you give me the most common a example? Yes, i data base stuff, ok.