задача 3

INSERT INTO Clients (Client_id, Client_Name, Address) VALUES ('1','Petar', 'Sofia')

INSERT INTO Courses (Course_id, Course_Name, Duration, Lecturer_Name) VALUES ('512','VM 2', '40', 'prof. Gosho')

INSERT INTO Course_Client (Client_id, Course_id, Date) VALUES ('1', '512', '2017-11-11')