Extensible select and enumeration types

and their elements in schema Risk_arm taking into account BASED_ON types


 activity_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Assigned_property
          Event_assignment
          Lessons_learned
          Risk
          Risk_assessment
          Risk_consequence
          Risk_control
          risk_criteria_select
          Risk_estimation
          Risk_evaluation
          Risk_identification
          Risk_impact
          Risk_impact_assignment
          Risk_perception
          Risk_perception_context
          Risk_perception_relationship
          Risk_perception_source_assignment
          risk_perception_source_item
          Risk_relationship
          Risk_treatment

 date_or_date_time_item - EXTENSIBLE SELECT

 documented_element_select - EXTENSIBLE SELECT
          Risk
          Risk_impact_assignment
          Risk_perception_source_assignment
          Risk_treatment

 event_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Risk_perception

 external_identification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Document_definition
          File

 measure_value - EXTENSIBLE SELECT
          any_number_value
          any_string_value
          length_measure
          plane_angle_measure

 property_assignment_select - EXTENSIBLE SELECT
          Event
          Risk_perception

 represented_definition - EXTENSIBLE SELECT
          Assigned_property
          Independent_property

 risk_impact_item - EXTENSIBLE GENERIC_ENTITY SELECT

 risk_perception_source_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Activity
          Activity_method
          Product