Description: XCoke Company delivered new Vending Machine for TRNC; the new machine has ability to accept payment by banknotes, coins and bankcards. Customer can chose the type of payment, and insert the target amount into the socket, if the inserted amount is greater that the product fees the machine should return the remaining money to the customer and then release the product. The machine has a set of sockets for the products, where every socket contains a specified amount of products Example, eight products. If product socket empty, and the user entered code of socket, the machine must show Attention about the product state. The machine should ask the customer if he want different product, else the machine must return the money back to the customer. The company has two employees, accountant and driver. The accountant is responsible about the accounting of sales, relationship with merchants, pricing and interaction with machine merchant technical and accounting stuff for solving issues. The driver has the locations of all vending machine. In regular basis, he must plane a route for filling machines with products. Driver must plane the best route for travelling all cities with minimal driving distance. Also he responsible of collecting money from machine, and reporting to the main office (accounting) about the last updated state of the machines, the company use Website for reporting from the driver, however, they have Desktop Application for retrieving the reports, and manage the accounting.

User purchase scenario: 1. Customer select money socket 2. Customer inserting an amount of money (recommended amount is the same product fees) 3. Select the product from the key board 4. If payment is adequate for buying the product, machine release the product, returns the remaining amount, finally, machine entered to waiting mode for next customer.

The company asks you to make the analysis of the database relations, attributes and constraints. Meanwhile, they ask you to do the implementing on Postgresql database server. They ask you to give them sample database state for testing the behavior of the relation. Finally, they want you to give them a sample queries for accessing the relation.

Please show the queries in SQL file format