Mr. Smith is the owner of a grocery store. He has a computer and a scale. He will buy a a barcode reader. He currently manages goods in his store using Excel. Each kind of goods (e.g bread, beef, apple...) has the following information: name, barcode number, number of available units, price per unit, provider name, and provider contact information. He currently checks out his customers' orders using a hand-held calculator and writes down the receipts manually. He inputs and updates the information of the goods in his store directly to the Excel spreadsheet. User stories implemented for Iteration 1: 1. As a user, I want to check out an order in store for a customer. 2. As a user, I want to add a new product into the system. 3. As a user, I want to update information (price, quantity) of a current product in the system. Tasks: 1. Write use cases with illustrated user screens for those three user stories. 2. Write an ER diagram for the data of this system. 3. Write SQL code to create the data tables for this system and insert sample data for them (e.g., at least 5 products and 10 orders)