Edgar Codd's 12 Rules Define What Makes a Database Truly Relational

Databases behind everyday apps store and organize large amounts of information, but how they do so depends on their underlying design. In 1970, computer scientist Edgar F. Codd introduced the relational model, which arranges data into tables made of rows and columns. Codd later proposed a set of rules describing what a genuine relational database management system should support, commonly called the 12 rules, though they are numbered from Rule 0 to Rule 12. The article illustrates these principles using a college management system that tracks students, courses, attendance, and exam marks, with each table linked through relationships. Key ideas include managing all data through relational capabilities, representing information consistently as table values, and enabling reliable access to any value using its table, key, and column.