Project on To Sketch the E/R diagram: 

A technology company provides offerings to its customers. Offerings are of two types; products and services. Offerings are identified by an ID and description. In addition, products are described by product name, standard price, and date of first release; services are described by name of the company's unit responsible for the service and conditions of the service. There are maintenance, repair, and other types of services. A repair service has a cost & is the repair of some product; a maintenance service has an hourly rate. Fortunately, some products never require repair. Thus, there are so many potential repair services for a product. A customer can purchase an offering, & the company needs to keep track of when the offering was purchased and the contact person for that offering with the customer. Unluckily, not all offerings are purchased. Customers are identified by an ID, name, address, and phone. When a service is performed, that service is billed to a customer. Because some customers purchase offerings for their clients, a customer may be billed for services he or she did not purchase, as well as for ones that were purchased. When a customer is billed for a service (although some may never require a service of any type), the company needs to keep track of the date the service was performed, the date the bill is due, and the amount due.