$4\mathrm{.}3$ Ashton wants to store the following data about S&S$\text{'}$s purchases of inventory:

item number

date of purchase

vendor number

vendor address

vendor name

purchase price

quantity purchased

employee number

employee name

purchase order number

description

quantity on hand

extended amount

total amount of purchase

REQUIRED

a$.$ Design a set of relational tables to store this data. Do all of the data items need to be

stored in a table? If not, which ones do not need to be stored, and why do they not

need to be stored?

b$.$ Identify the primary key for each table.

c$.$ Identify the foreign keys needed in the tables to implement referential integrity.