What ia an ERD. Define the RED related terms, including entities, attributes, cardinalities and relationships

 An ERD (Entity Relationship Diagram) is a graphical depiction of the relationships between database entities (Chen, 1976). It aids in the identification and organisation of data in a logical manner, which is essential for database design. Following are some popular terminology for ERDs:

 Entities: An entity is a real-world thing or notion with its own distinct identity that may be represented as a database table (Elmasri & Navathe, 2010). In a school database, for example, entities may comprise students, professors, courses, and departments. 

Attributes: An attribute is a feature or property of a thing. A student entity's characteristics could contain, for example, name, ID number, and GPA (Connolly & Begg, 2014).

 Cardinalities: The number of occurrences in each entity defines the connection between two entities. It is represented by symbols such as "1" or "many" (Silberschatz, Korth & Sudarshan, 2010). For example, the cardinality between a student object and a class entity might be "many-to-many," which means that one student can attend several classes and each class can have multiple students. Relationships: A relationship is a link between two database entities. Relationships are classified by cardinalities and might be one-to-one, one-to-many, or many-to-many (Connolly & Begg, 2014). In a school database, for example, there may be a link between the student entity and the instructor entity with a cardinality of "many-to-one," implying that many students could have the same teacher.

References: 

Chen, P. P. (1976). The Entity-Relationship Model—Towards a Unified View of Data. ACM Transactions on Database Systems (TODS), 1(1), 9-36.

 Connolly, T., & Begg, C. (2014). Database systems: A practical approach to design, implementation, and management. Pearson.

 Elmasri, R., & Navathe, S. B. (2010). Fundamentals of database systems. Pearson Education. 

Silberschatz, A., Korth, H. F., & Sudarshan, S. (2010). Database system concepts. McGraw-Hill.