We are creating a database to store car brands, actual cars and the extras in the cars.
- For a brand, we want to store the ID and the name (e.g. 1 BMW, 2 Audi, 3 Citroen)
- For an extra feature , we want to store the ID, the name and the price (e.g. 1 Sunroof 2000, 2 Sports_gearbox 3000, 3 Turbo_engine 5000 - the price must always be bigger than 1000)
- For a car, we want to store the ID, the name, the base price (e.g. 1 BMW_316i 60000, 2 Audi_A5 80000, 3 Citroen_C2 10000 - every field must have a value!).
- For the cars, we also want to store the brand of the car and a list of the extras for the car.

P1.
	a. Create the tables with the appropriate constraints
	b. Insert minimum 5 rows for all tables
	c. Delete the most expensive car
	d. Double the price of the least expensive extra
	e. Undo the delete and the double

P2.
	a. Create a view that lists all cars (mandatory fields: brand name, car name, car base price). Do not show the cars if the car price is bigger than the average car price
	b. Create a view that uses all fields of the cars table, and adds the TOTAL price of the car (base price + the total price of all the extras)
	c. Add an extra field to the car table: car_isFancy. This field should be 1, if the number of extras of the car is higher than the average number of extras for the car's brand.
	d. Add an extra field to the car: car_realPrice. Set the value of this field based on the view created in exercise B

P3
	a. List the brand name, car name, base price, extra name, extra price for all fancy cars, ordered primarily by the brand name, and secondary descending by the car name's second letter. If there is no extra for a car, then the text "no extra" should be displayed instead of the non-existant fields.