An entity relationship is a graphical presentation of a real database that usually starts with a relational database that is responsible for storage of data in tables (Carlo, 1997). It shows the relationships that exist between entities. Some data in those given tables have a reference to data in other tables. This data program helps designers to create precise and useful conceptual models. For a computerized local video store to be effective, a good database is vital. This will be achieved only if there is a perfect ER model that is intended to guide in the formation of the database.
However, there are some regulations that must be adhered to in order to have smart records of the available videos and to avoid conflict of the videos that have been rented. These business rules are as follows. A customer can rent as many videos as he wishes. These videos can be of the same type or different types. There is a limit of time duration that a customer is allowed to stay with the videos after renting. If a customer exceeds the time specified, he/she is prone to be fined depending on the time that has been exceeded. Two customers cannot be rented the same video at the same time. If the video has been taken by someone, the system should be able to alert whenever the video is requested by a customer. Each video is identified by its title and a unique number that is different for all videos. This will help the management to know the number of videos that are available and also to avoid a situation where videos with the same title are not confused. Video details that will be captured and they will include the following; Video title, video number, and the rental fee. There is a member’s area. This captures member’s details. Each member is identified by a unique number that is different for all customers. This will enable the management to detect any form of impersonation. Besides, it will enable the management to know the number of movies that each member has. The members details that will be captured include; member name, member phone number, the videos that he has rented and member id.