The EDM is an implementation of the Entity-Relationship model (commonly called the E-R model). It depicts entities and their relationships. The EDM is a view of the data store that your application will use.
Before we explore deeper into our Security
DataModel, let's discuss entities, entity types, relationships, and how these are all represented.
An entity essentially models individual, real-world objects such as employees and customers. Such objects contain information pertaining to the entity. An entity is something that is uniquely definable, distinctly identifiable, and can have one or more of the following properties:
It should be identifiable easily through the data that it holds
It should have properties that can hold scalar values that represent the entity's data
It should only contain data, not methods or operations on the data
It can have entity relationship information such as how one entity is related to another...