Counting Rule 0 together with Rules 1–12, how many rules did Dr. E. F. Codd…

Concept

For an inclusive integer sequence from a to b, the number of members is b − a + 1. Codd’s requirements are commonly called the “12 rules” for Rules 1–12, while Rule 0 is the foundational rule placed before them.

Application

1. The numbered sequence begins at Rule 0 and ends at Rule 12.

2. Apply inclusive counting: 12 − 0 + 1 = 13.

3. Thus Rule 0 plus the twelve rules numbered 1 through 12 gives a total of 13 rules.

Cross-check

• Foundational part: Rule 0 contributes 1 rule.

• Numbered set: Rules 1–12 contribute 12 rules.

• Independent total: 1 + 12 = 13.

Result

Therefore, when Rule 0 is included as the stem specifies, the total is 13.