What is the type of index that is automatically built on EMP_CODE on the EMPLOYEE table? ___________________________________.

We want to improve the speed of a query that is run to show who is assigned to each vehicle. On which table would we build the index? _______________________ and on which attribute on that table? ______________________________.

Table Name: FLEET Table Name: EMPLOYEE EMP CODE VEH ID L NAME Davolio Grubb Leverling Penn Buchanan Smith King Callaharn Dodsworth Klein Johnston Phillips Basil Sunn Barker VEH ID VEH TYPE 10 20 30 40 50 Truck-FLOATER 2 Truck Truck Truck Truck Van Line ServiceTruck 4 6 4 70 80 100 110 120 130 140 150 4