The relational database series of logically related two-dimensional tables or files to store information in the form of a database. The files that Wal-Mart will create for on-line ordering would be Order Number, Order Date, Customer Number, Delivery Address, and Amount Ordered. Employee files would also have unique data, Employee Number, Date of Hire, Employee Name, (first and last). Regular customers that place orders via Wal-Mart’s website also have customer files with their customer number, customer name and contact service person. While there may be many fields to a file each field has a unique Primary Key. The databases used at Wal-Mart are CRM system and Retail Link. CRM helps with the tracking of customers, while Retail Link is a decision support system for suppliers and retailer. The brand of database software that is used is NCR’s Teradata Software, believed to carry approximately 583 terabytes.