a. Include entities, relationships, attributes, unique identifiers, connectivities, weak entities (if any), and associative entities (if any).
b. Specify partial/complete completeness and disjoint/overlapping constraints, and include subtype discriminators for supertype-subtype relationships.The planning and analysis phase of the database design process has provided the following data requirements for a company called Reliable Rentals, which rents out vehicles (cars and vans). The Company has various outlets (garage/offices) throughout Glasgow. Each outlet has a number, address, phone number, fax number, and a manager who supervises the operation of the garage and offices at each site.
Each site is allocated a stock of vehicles for rent; however, individual vehicles may be moved between outlets, as required. Only the current location for each vehicle is stored. The registration number uniquely identifies each vehicle for rent and is used when renting a vehicle to a client.
Clients may rent vehicles for various periods of time (minimum 1 day to maximum 1 year). Each individual rental agreement between a client and the Company is uniquely identified using a rental number. Information stored on the vehicles for rent include: the vehicle registration number, model, make, engine size, capacity, current mileage, due date, daily rent rate, and the current location (outlet) of each vehicle.
The data stored on a rental agreement includes the rental number, the client’s number, name, address and phone number, date the client started the rent period, date the client wishes to terminate the rent period, the vehicle registration number, model and make, the mileage before and after the rent period. After each rental a member of staff checks the vehicle and notes any fault(s). Fault report information on each vehicle is stored, which records the name of the member of staff responsible for the check, date checked, whether fault(s) where found (yes or no), the vehicle registration number, model, make and the current mileage.
The Company has two types of clients: personal and business. The data stored on personal clients includes the client number, name (first and last name), home address, phone number, date of birth and driving license number. The data stored on business clients includes the client number, name of business, type of business, address, telephone and fax numbers. The client number uniquely identifies each client and the information stored relates to all clients who have rented in the past and those currently renting a vehicle.
Information stored on the staff includes staff number, name (first and last name), home address, home phone number, date of birth (DOB), sex, National Insurance Number (NIN), date joined the Company, job title and salary. Each staff member is associated with a single outlet but may be moved to an alternative outlet as required, although only the current location for each member of staff is stored.