Following is an ER diagram for a call center. It illustrates the internal working structure of the call center as well as how a query of a customer is handled inside the system. Here the entities are represented using square box shapes, the attributes using oval shapes, and the type of relationship using diamond-like shapes. Straight lines or links are used to connect different entities.The various entities involved within the system include the call center, the customer, the department, the employee, the manager, and the query made by the customer.
