DBMS Case Study: QRentals database system

QRentals (QR) is a private-owned business located in a large city that specializes in car hire service.

The management of QR has approached you to build a relational database that will be used as the

most critical backend software component in their enterprise management system so that the

relevant business data will be recorded appropriately and further information query will be processed

efficiently. The proposed database system requires efficiently to track all QRs vehicles, customers,

employees and relevant rental activities. Consider the following user requirements carefully and

design a database conceptual schema (i.e. E-R model) to support such an application.

The company owns a large number of cars for hire. These cars are usually parked in a number of

locations (belonging to QRs property) in the city-wide, each location at a distinct address. Each car

has a unique registration number which can used as an identifier. The cars make and model,

manufactured year, as well as the number of seats must be recorded. All cars in this case study

hypothetically fall into a number of categories such as minivan, SUV, sedan, ute, luxury limos, etc. The

daily hire rate of a vehicle is dependent on its category; for example the daily price of an ordinary

sedan is approximately $35 while hiring a minivan may need paying up to $70 per day. In addition,

each car has been commercially insured. The related insurance details are required to store in the

database, which include the policy number, amount of premium, insurer name, policy start date and

expiry date.

The system also needs to handle two different kinds of people: QRs employees and customers. An

employee, whose main duty is to process booking request from customers, is identified by a unique

identification number, and has a name consisting of first name and last name. Other data on

employees need to record are their birthdate, skill level, annual salary and the working location which

normally is located at where the QR cars have been parked. For each customer, in addition to an

identification number assigned, it is necessary to record his/her full name, license number, address,

and phone number. In addition, the customers are generally categorized into two distinct types:

individual and corporate. For an individual customer, whether the customer has a personal life

insurance or not is recorded. For a corporate customer, the organization name, Australian Business

Number (ABN) and whether the business travel special deal is applicable or not are recorded.

To rent a car from QR, the customer must contact the company by a phone call. An employee of QR

will make a booking through the phone. QR often also stores details of some customers who have

made enquiries through phone calls but have not made actual booking due to availability issue or a

factor of price. The database keeps their details on record so that QR may follow up with them at a

later stage particularly in promotional activities. For each booking, a reservation number will be

created automatically. A brief description of reservation, the required category of car and the booking

date will be recorded. Then the customer will go to a particular location to pick up the car at the

scheduled start date (there is no concern what time to pick up it). After the rental activity ends, the

customer returns the car to a location (the so called drop off location) which may be different from

the pickup location. The database must keep track of relevant rental details such as pick up/drop off

location, start date, end date as well as the cost in the system. Finally, the database also stores an

image for each vehicle so that the prospective customers can conveniently view them online before

their hiring.

Question - Assumptions and Business rules

Provide assumptions and business rules relevant to your ERD. Please write in more detail rather than bullet points

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