Elaborate on why implicit requirement changes are not permitted

What will be an ideal response?

Every time the set of requirements is changed, the conceptual model has to be changed accordingly, and the changes in the requirements must propagate as applicable through all of the subsequent steps: modeling, creating the database, creating front-end applications, deployment, use, and administration/maintenance. No implicit changes of requirements are permitted in any of the database development steps. For example, during the database implementation process a developer is not allowed to create in an ad hoc way a new database construct (e.g., a database table or a column of a database table) that is not called for by the requirements. Instead, if during the database implementation process it is discovered that a new construct is actually needed and useful, the proper course of action is to go back to the requirements and augment both the requirements document and the conceptual model to include the requirement for the new construct. This new requirement should then be reflected in the subsequently augmented database model. Only then should a new database construct actually be implemented.