Employee Database.

• Departments have:
  • name
  • head
  • parent department
  • possible sub-departments
  • location
  • number of employees
• Employees have:
  • SSN
  • name
  • date of birth
  • date when he/she was hired
  • sex
  • office phone
  • salary
  • skills
• Create Oracle tables corresponding to the structure above and don't forget to put additional restrictions:
  • salary should be positive
  • an employee cannot be older that 80 and younger that 14
  • an employee cannot work for more than one department
  • an employee must work for some department
  • an employee cannot be hired before he/she was born
  • when a department is removed all employers of the department are fired
  • head of a department can retire or be fired
  • a department cannot have more than one parent department