Mapping Between Different Data Models Typically, independently created data sources are based on different data models. This reflects the fact that they have different scopes, though often with some common elements, and represent different views of the world. For the sources to be integrated, there must be mappings between their data models and a third, common data model. When the number of sources to be integrated is large, the problem of mapping them is extremely complex and difficult. There are, however, technologies that can help the data engineer to perform this task.