This chapter explains the (technical aspects of the) nevisIDM data model, which involves the entities it is based on as well as the relations between those entities. The next figure shows a simplified version of the nevisIDM data model. "Simplified" meaning it shows only the most important entities and relations in nevisIDM. The actual implementation of this model, i.e., the nevisIDM with its tables and views, is much more complex. For most nevisIDM administrators and users, however, understanding the simplified model will give enough insight into nevisIDM required for all the tasks that will be executed with the help of nevisIDM.