2.1.1. What is ERD?¶

ERD is stands for an entity relationship diagram, is a high level data model in the form of graphical representation that describes relationships among people, objects, places, concepts or events within a database system. An ERD uses data modeling techniques that can help define business processes and serve as the foundation for a relational database. Simply it simulates the real world concepts.

2.1.2. Why ERD is useful?¶

1- It develops a very simple and easy design view of data (conceptual design).

2- ER diagrams can be shared with colleagues and their simplicity makes them ideal even for non-technical stakeholders.

3- As it provides a visual starting point for database design, it can also be used to help determine information system requirements throughout an organization.

4- The diagram also makes it easier to spot potential problems and correct them before moving on to the later stages of the design process.

5- After a relational database is completed, an ERD can still serve as a reference point, should any business process re-engineering be needed later.

V.I. Note: In spite of considering ERD as a conceptual design model, ERDs can generally depicted in one or more of all other model types (logical, physical).