 Welcome back MechanicalEI. Did you know that an ER or Entity Relationship Model defines a data or information structure which can be implemented in a database? This makes us wonder, what is an Entity Relationship Model? Before we jump in, check out the previous part of this series to learn about what a database modeling is. Now, an Entity Relationship Model or Simply Put, an ER model is a graphical approach to database design. It uses entities and their relationships to present real-world objects. An entity is a thing or object in the real world that is distinguishable from the surrounding environment. For example, each employee of an organization is a separate entity. Entities are represented by means of their properties called attributes. All attributes have values. For example, a student entity may have name, class, and age as attributes. The association among entities is called a relationship. For example, an employee works at a department. Here, works at is called a relationship between employee and department. The ER model has the power of expressing database entities in a conceptual hierarchical manner. As the hierarchy goes up, it generalizes the views of entities. And as we go deep in the hierarchy, it gives us the detail of every entity included. Going up in this structure is called generalization, where entities are clapped together to represent a more generalized view. For example, a particular student named Mira can be generalized along with all the students. The entity shall be a student and further, the student is a person. The reverse is called specialization, where a person is a student and the student is Mira. Hence, we first saw what entity relationship model is and then went on to see what generalization and specialization are. So, here are the top mechanical EIs of our last videos. In the next episode of Mechanical EI, find out what an extended entity relationship model is.