This example depicts the ER diagram for library management system which involves various entities and Attribute likes books, publisher, member etc. An entity relationship diagram (ERD), also defined as an entity relationship model, is a graphical depiction of relationships between people, things, locations, concepts, or events in an information technology (IT) system. An ERD employs data modeling approaches to assist in the definition of business processes and as the foundation for a relational database. Entity relationship diagrams serve as a visual starting point for database architecture and may also be used to assist establish information system requirements throughout an organization. After a relational database is implemented, an ERD can still be used as a reference point for future debugging or business process re-engineering.