Developers often create maps between objects within an application. One definition of a Mapper is an "object that sets up communication between two independent objects." A Data Mapper is a "layer of mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself. " [Patterns of Enterprise Architecture, ISBN 0-321-12742-0].

You provide the database and the objects; iBATIS provides the mapping layer that goes between the two.