Abstract the storage of an app

[Panos Laganakos]

Hello,

I'm trying to think of an OO way to abstract the storage of an
application I am working on.

The classes are (example):

FamilyMember (base class)
Family (container class)

I've been thinking of using a FamilyDoc class to interface the Family
container class to a storage location (particularly, in XML).

I want to be able to use another backend for storing that data, ie
SQL(ite).

What would you suggest as a design pattern for something like this?