This School ER Diagram Example will assist you in visualizing how entities in a database relate to one another, as well as the attributes of each entity. This example depicts entities associated with the school system. An Entity Relationship Diagram (ERD) shows the relationships between entities in a database. It is commonly referred to as an ER Diagram. In DBMS, an ER Diagram is essential for database design. In today's business world, an ER Diagram previews all of the requirements requested by users. It is then passed on to the database administrators to design the database. An Entity Relationship Diagram (ER Diagram) illustrates the relationship between entities in a database.