Which statement best describes the 13 rules used to determine if a DBMS is relational?

• A. They are the 13 rules defined by Codd to determine relational DBMS status
• B. They are guidelines for database performance tuning
• C. They are data security standards
• D. They are user interface guidelines

Answer: (A)

In relational databases, these rules define what qualifies a DBMS as relational. They lay out the fundamental properties a system must support—data should be represented as tables, accessible through a logical mechanism rather than navigating physical storage, and manipulated via a comprehensive language with proper handling of NULLs, integrity constraints, and data independence. This framework is exactly what the statement describes: the rules defined by Codd to determine relational DBMS status. The other choices point to topics like performance tuning, security standards, or user interface guidelines, which are not what these rules address.