Read and analyse the following specification of a sample database domain.
A transportation company would like to create a database to record some of its operations. The company owns and uses several busses to implement transportation services between the cities.
The company employs administration staff members, drivers and mechanics. A common description of an employee consists of a unique employee number, first name last name and date of birth. Additionally, drivers are described by a unique driving licence number and category of a driving licence. Mechanics are also described by a list of qualifications acquired in the past together with a date when each qualification has been acquired.
The company supports a number of transportation services. A service starts at a city, passes through a number of intermediate stops and ends in another or the same city. An origin location, a sequence of intermediate stops, and a destination location of a service are described by unique addresses. An address consists of city name, street name and building number. Each intermediate stop has a unique number in a sequence of intermediate stops within a transportation service.