Did Codd's 12 rules ever get fully implemented?
The '12 Rules,' or the Codd's 12 commandments, were intended as a checklist to identify true relational database systems. While many systems claim to be relational, few fully adhere to all twelve rules. Often, practical considerations or business pressures lead to deviations. This can result in systems that offer relational-like features but lack the complete theoretical integrity of a truly relational implementation.
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