8.7 Rule book and fact model maintenance 231 8.7.1 Adding a rule If an additional rule is required, 1. the appropriate rule statement should be added to the rule book, with an appropriate status and ef- fective date; 2. if the rule is a data rule, a. the term that is the subject of that rule statement should be identified, along with any fact types involving the terms that have been used in formulating that rule statement; b. the entities or attributes described by the terms identified in step a should then be identified, along with the relationships described by the fact types identified in step a; c. each database table, column, or foreign key implementing the entities, attributes, or relation- ships identified in step b should then be identified; d. the message types, user interfaces, and/or data elements described by the terms identified in step a should also be identified; e. additional logic to ensure compliance with the new rule should be added to each database table, column, foreign key, message type, user interface, and data element identified in steps c and d. 3. if the rule is an activity rule, the term that is the subject of that rule statement should be identified;