A diagrammatic APPROACH to database architecture in which real-world things are represented as entities and relationships between them are indicated is known as an Entity-Relationship model. Given below is an image of a sample ER diagram for a student studying in college.

The definition of the given terms are as follows:

• Entity: A real-world object with attributes that indicate the object's qualities is DEFINED as an entity. A student, an employee, or a teacher, for example, symbolizes an entity.
• Entity Type: A group of entities with the same attributes is referred to as an entity type. An entity type is represented by one or more linked tables in a database. Entity type or attributes can be thought of as a trait that distinguishes the entity from others. A student, for example, is an entity with properties such as student ID, student name, and so on.
• Entity SET: An entity set is a collection of all the entities in a database that belongs to a given entity type. For instance, a group of all students, employees, TEACHERS, and so on represents an entity set.