Valet Hair is a popular hair salon located in Sydney CBD where its revenue has grown at 30% last year. To catch up with the rapid growth, Valet Hair has to create a new way of keeping track of its customer: hairdresser and service information, and you are invited to design a database for Valet Hair. First, Valet Hair needs to keep customer information such as name, email, date of birth and contact details. Meanwhile, it also needs to keep the information about their hairdressers such as their names, availabilities, specialisations and contact details. At Valet Hair. customers have to book the service online. The available hairdressers will then be matched against each booking according to their specializations. Note that each service can involve more than one hairdressers as they will be responsible for different tasks. In order to calculate wages of hairdressers, it is important to record the hours they spent in a particular service. In addition, since Valet Hair offers various types of services from haircut and styling, to treatment and perming, different types of services will be charged at different prices. To attract more customers, Valet Hair promotes a referral policy to its existing members. Each member will be given $10 reward on top of their account balance for each successful referral and each customer can only be referred once