Prepare an entity-relationship (ER) . Be sure that your ER diagram has the following elements: entities; relationships between entities; primary and foreign keys, and other necessary columns for each entity.

User Requirements:

Global Trading (GT) is a wholesale business that sells a variety of products; its customers are other businesses. Also GT's vendors are other businesses. GT has the following business rules for the database that the company wants you to design:

A product is supplied by one or more vendors and a vendor may supply one or more products.

Each sales order is prepared by one sales rep (salesrep). Each salesrep can prepare many sales orders.

A sales order is written for a single customer, though a customer can have many orders.

A single sales order can be for one or more products ordered.

Besides primary and foreign key columns, the GT database must be able to store data about the following data items:

- Product name

- Customer name, phone number, and balance due

- Date of order

- For each sales order, products ordered along with the quantity ordered and price per unit

- Vendor name and phone number

- Quantity on hand for each product; vendor who supplied the product

- Salesperson name and phone number

- Some salesreps supervise other salesreps the database should allow identifying who supervises who.