An organizer commissioned us to design a database for an inventory management system. They provide a summary of requirements as below. A supplier is identified by his/her id. We also record his/her name, phone number and supplier type. A supplier may have several supplier types. A product is identified by its id. We also record its name, price, production date and availability. A supplier must provide one or many products. Each product must be provided by one supplier. A manager is identified by his/her id. We also record his/her name, phone number, working hours and job description. Each manager is hired by one supplier. A supplier may hire zero or many managers. A manager can oversee zero or many products. Each product can be overseen by zero or many managers. An order is identified by its id. We also record its order date, status and price. We are interested in the number of products in each order as well. An order must involve one or many products. Each product is involved in at most one order. Each shipping is identified by its id. We also record the shipping address, shipping company and status