a. Identify three potential users and design a subschema for each. Justify your design by explaining why each user needs access to the subschema data elements. - To fill out a sales order, the sales order entry clerk needs access to the following data: - item number - description - quantity-on-hand - price - customer name - shipping address - credit limit - account balance - To create and mail a bill (invoice), the billing clerk needs access to the following data stored in the database: - customer name - customer number - billing address - item numbers - quantity sold - price - terms - To manage inventory, the inventory control department needs access to the following data stored in the database: - item number - description - quantity on hand - To purchase inventory, the purchasing department needs access to the following data stored in the data base: - item number - description - quantity on hand cost Use Microsoft Access or some other relational database product to create the schema tables. Specify the primary key(s), foreign key(s), and other data for each table. Test your model by entering sample data in each table