The table below has basic information about Sales staff and their sales for a small appliance sales chain. It shows the employee, the items they sell as well as which store they work in.
SALES(Emp_Name, Emp_ID, Make, Grade, Retail_Price, Wholesale_Price, Serial_No, Commission, Store_Address, Date, Store_Phone, Model)
The following functional dependencies apply and there are no redundancies present:
Store_Address -> Store_Phone
Grade -> Commission
Emp_ID -> Store_Address
Serial_No -> Model, Make
Emp_ID, Serial_No -> Date, Retail_Price
Serial_No ->Wholesale_Price
Emp_ID -> Grade
Emp_ID -> Emp_Name
3.1 Find the Primary Key of the SALES relation.
3.2 Decompose the SALES relation into 3NF. Show the final schema in full with all primary keys and foreign keys mark appropriately.
3.3 The following FD also holds true:
Store_Phone-> Store_Address
Which relation in your decomposition would it map to? Test that relation to show that it is still in 3NF. Show your working.