What is an ER diagram? An Entity Relationship (ER)
An Entity Relationship (ER) diagram is a graphical representation of entities and their relationships to each other. It is a modeling tool used to represent real-world entities and the relationships between them in a visual form. The ER diagram is a key component of the Entity-Relationship model, which is widely used in software engineering to design and develop databases. An ER diagram consists of three main components: entities, attributes, and relationships. Entities: An entity is a real-world object, concept or event that exists independently and has a unique identity. For example, in a university database, entities can be students, courses, professors, and departments. Attributes: An attribute is a characteristic or property of an entity. For example, in the student entity, attributes can be the student ID, name, age, and gender. Relationships: Relationships are the connections between entities. They represent how entities are related to ...