What Is Entity Data Model (EDM)?

Entity data models are the heart and soul of any suitable database. They keep your data structured, organized, and easy to find. An entity data model (EDM) refers to a set of concepts that describe data structure, regardless of its stored form. This model uses three key concepts to describe data structure: entity type, association type and property. An entity type describes an object in your database and is represented by a box in the diagram. Each entity has properties that define it and describe its behavior. For example, if you're storing information about people in your database, each person would have a first name, last name and email address as properties. Association types describe how one entity relates to another entity or entity. In your database about people, for example, you might have an association type "friends" between people so that you can keep track of who their friends are. You can also use association types to represent indirect relationships between entities (i.e. , when one entity has multiple roles). Properties are attributes assigned to entities or associations to describe them further or store specific values for them. So, you're trying to figure out how to build your data model. You've got some entities, and you need to figure out what attributes they have and their relationships with each other. First thing first: let's talk entity types. Entity types are the fundamental building block used to describe data structure within the entity data model (EDM). They serve as templates for entities that represent a specific object with a unique entity key within an entity set, a collection of instances of a specific entity type. In the conceptual model, entity types are constructed from properties and describe the structure of top-level concepts. An entity set is grouped logically in an entity container. An entity container may contain zero or more entities of different types.