w4111-project-Relational Database Design and Front-End Application

second hand market databsae using PostgreSQl server and the front-end design

Our project focuses on the database of second-hand trading pattern. We want to build a platform that can query second-hand transaction information at any time. We will have six entity sets that contains User, Product, Category, Order, Delivery and Payment. Because it is a second-hand trading database, there are two logical patterns of trading: purchasing and selling. From the E/R diagram, every product is supplied by exactly one user which contains a unique user id, a name, an address, an email and searching history(text). And for every product which contains a unique product id, a category id, a name, a price, an address and a description, it is categorized by exactly one category. This relationship marks the selling pattern of second-hand goods. Moreover, every order is placed by exactly one user. This relationship marks the purchasing pattern of second-hand goods. After the order which contains a unique order id is placed, it forwards exactly one delivery information like a unique track number and an address. Every order has exactly one payment information like a unique payment id and a method. The second-hand market database can clearly show the current popular online shopping mode, that is, buyers can also be sellers. Moreover, second-hand E-commerce is a good start of recycling, which contributes to green finance. For limitations, because our database focus on second-hand trade, we lack some entity sets that are common in traditional E-commerce like Shopping Cart and Discount.