Modeling Repeating Groups:

Definition and Explanation:

A set of two or more multi-valued attributes that are logically related is called the repeating group.

E-R Diagram:

The E-R diagram of the EMPLOYEE entity with three multi-valued attributes is given below.

The 'Degree', 'Exam-Board' and 'Marks' are logically related and form a repeating group. You can remove the repeating group attributes and create a new entity such as QUALIFICATION. The E-R diagram is given below which shows the relationship of EMPLOYEE and QUALIFICATION entities after removing the mufti-valued attributes. There is one-to-many relationship from EMPLOYEE to QUALIFICATION.

Relevant Articles: The Entity-Relationship Model and the Entity-Relationship Diagram (E-R Diagram) Basic Elements of ER (Entity-Relationship) Model Existence and Referential Dependency in Database Modeling Multiple Valued Attributes Modeling Repeating Groups Modeling Time-Dependent Data Supertypes and Subtypes Entities Aggregation Generalization and Specialization Case Scenarios ER Model Projects