What is ERD , definitions of entities , attributes , cardinalates , relationships.

 WHAT IS ERD?

ERD stands for Entity-Relationship Diagram, a graphical representation of entities, attributes, and relationships in a data model. The purpose of an ERD is to help design and visualize a database schema in a clear and organized way.

Meaning of the terms related to the ERD .

Attributes - it is a vivid property of an entity .for example 'customer' entity might have attributes such as (" name, address and phone numbers"). it is represented by an oval and it is attached to entity(Brady.M,2010).

Entities- an ERD, an entity is represented by a rectangle, and its name is written inside it. For example, "Customer" is an entity that might be included in a database scheme.An entity is a concept or object in the real world that can be identified and described.(Song,1995).

Relationships - it is connection between two or more entities , it is represented by diamond and always described by a verb.or example, a "Customer" entity might have a relationship with an "Order" entity, where the verb "places" describes the relationship between them.

Cardinalates - it is a fixed property of relationship between two entities .In an ERD, cardinality is represented by symbols such as "1" and "N.(Evans,1995).It describes the number of instances of one entity that can be related to the number of instances of another entity .For example, a "Customer" entity might have a relationship with an "Order" entity, where one customer can place many orders, but each order is placed by only one customer.

In summary, an ERD is a tool that can help you design and organize a database schema by visually representing the entities, attributes, cardinality, and relationships in a clear and concise manner.

Refrences -

Song, I.Y., Evans, M. and Park, E.K., 1995. A comparative analysis of entity-relationship diagrams. Journal of Computer and Software Engineering, 3(4), pp.427-459.

Brady, M. and Loonam, J., 2010. Exploring the use of entity‐relationship diagramming as a technique to support grounded theory inquiry. Qualitative Research in Organizations and Management: An International Journal, 5(3), pp.224-237.