Relational Model

Figure 2. Relational Model provides an overview of the table content, table column/attributes and the relationships that connects them. The identified relationships are as follow: a single customer can make multiple sales (1:M), a single sale contains specific set of sales details (1:1), the same payment could be used for multiple sales (1:M). Furthermore, an order details can contain multiple books or product items (1:M), a single author can have multiple books in the store (1:M) just as a single publisher can publish many different books and authors (1:M). Our database features 9 tables: Customers, Sales, SalesDetails, Product, Product_Categories, Books, Authors, Publisher and Payments. The Customers table consists of attributes/columns such as C_ID (Primary key), CustomerName, Street, City, State, zip, email and phone number. The table connect with Sales via its primary key C_ID and the attribute/column C_ID and their relationship as a foreign key. Sales also features its own primary key Sales_ID and a second foreign key Payment_ID, which features a relationship with the Payments table with its primary key Payment_ID, additional columns/attributes include: P_Type, AuthNo, Post_date, Customer_Name, TranNo.
The Product table also features Product_Name, Category_ID, quantity on hand and Qty_sold, it only contains one foreign key Category_ID that connect to the Product_Categories table and its primary key Category_ID. The also features the columns Item_type and