A database model that describes the attributes of entities and the relationships among them. An entity is a file (table). Today, ER models are often created graphically, and software converts the graphical representations of the tables into the SQL code required to create the data structures in the database. See
data model and
dimensional modeling.
Building an Entity Relationship Model
The Erwin modeling program from CA Technologies stands for Entity Relationship for Windows. In this order processing example, the tables for customers and orders are drawn graphically, and Erwin turns the graph into the appropriate SQL code for the target database. (Example courtesy of CA Technologies, Inc.)