knhf Aguilar

It's crucial to distinguish between the degree of a relationship and the cardinality of a relationship. These are often confused but are completely different concepts. Degree answers the question: "How many different entity types are involved?" It's about the breadth of the relationship. (e.g., Is it between 1, 2, or 3 tables?). Cardinality answers the question: "How many instances of one entity are related to instances of another entity?" It's about the depth or the count of the relationship. Cardinality types include one-to-one, one-to-many, and many-to-many.For example, the relationship Student <-- Enrolls_in --> Course has a degree of 2 (it's binary) and a cardinality of many-to-many (a student can enroll in many courses, and a course can have many students). A data modeler must define both the degree and the cardinality to accurately represent the business rules in the database schema.