Data modeling is done for the structured data environment. The purpose of the data model is to allow a long-term effort to be coordinated across multiple groups of developers. There are three levels to the data model – the high level, the mid level, and the low level. These levels are called the ERD, the dis, and the physical model. The data model consists of definitions, relationships, keys, groupings of data, attributes, “type of” relationships, multiply occurring relationships, and foreign keys. Because of the similarity of business across different organizations there are generic data models. As a rule the data model is for the granular data of the corporation exclusively.