ER Diagram and Database Table Stracture for Call Center Management System

One day I was asked to submit an ER diagram and Database structure on call center management system in our IT institute.That day I spend a long time in internet searching for references on Call Center Management system.But I did not get anything to satisfy me.I collected some Information on Call Center Management and tried my best to design an ER diagram and Database Table Structure. Today I am going to upload the diagram and the database Table structure for your help

Before handover the ER Diagram to you I thing it will be good to introduce you with ER diagram.

What is ER Diagram?

ER diagram is a graphical representation of entities and their relationships to each other in database.ER Diagram uses three spacial symbol to represent three different type of information.Boxes are used to represent entities. Diamonds are used to represent relationships and ovals are used to represent attributes.Peter Chen introduced Entity Relationship model in 1976

What is Entity?
Peter Chen defined an entity as "a thing, which can be easily identified". In a logical sense, entities are like a table, which contain columns and values in rows. Ex: Student_Details,  Employee_Details etc.

What is Attribute?
An attributes is a property of a given entity, for example, Roll_No is a property(attribute) of Student_Details entity. Attributes are like a column in a table.

What is Relationship?
Chen defined a relationship as "an association among entities". For example teachers  teaches student.In this situation this relationship could be named as TEACH.

Your ER Diagram and Data structure are given below....

ER Diagram for call center management system

Table Structure