An Entity-Relationship (ER) Diagram is a visual representation of the structure and relationships between entities in an Online Car Rental System. This diagram shows how entities such as Customers, Cars, Rentals, and Contact Details interact with each other through tables, fields, and attributes. The ER Diagram illustrates how data can be stored in order to optimize efficiency when managing car rentals online. It serves as a helpful tool for system administrators to visualize the structure of their data management system. With EdrawMax, you can download this template and customize it 100%, like importing images from your computer or even sharing the file into VSDX format.