Model the following cases by ER diagrams
The following descriptions are about the inventory information.
a) Each product item has ID, description, quantity in the inventory, unit price and a supplier.
b) Suppliers have unique ID, addresses, phone numbers, and names.
c) Each address is made up of a street address, a city, and a postcode.
d) The purchase order may consist of one or more product items.
e) Each purchase order has date, quantity for each items, total value