Format

      BASED ON  field-name

1  –  Parameters

1.1  –  field-name

    Specifies the field name on whose properties you are basing a new
    field element.

2  –  Description

    The BASED ON field property bases the properties of a new field
    element on one that already exists.

    You must have privilege to read a field element to be able to
    base other elements upon it.

    You can use BASED ON field properties to define several fields
    related to a base field and to each other.

    You can use the BASED ON field property to give individual names
    to field elements that share the same properties. This allows you
    to uniquely refer to these field elements in record elements.

    If you want the new field to have additional properties not found
    in the base field, you can specify the additional properties in
    the DEFINE FIELD or CHANGE FIELD command.

3  –  Examples

    1.CDO>  DEFINE FIELD SUPERVISOR_BADGE_NUMBER
      cont>   BASED ON BADGE_NUMBER
      cont>   VALID IF SUPERVISOR_BADGE_NUMBER > 500.

      In this example, the DEFINE FIELD command bases SUPERVISOR_
      BADGE_NUMBER on the BADGE_NUMBER field element. The VALID
      IF property is an additional property that is unique to
      SUPERVISOR_BADGE_NUMBER.

    2.CDO>  DEFINE FIELD MANAGER_BADGE_NUMBER
      cont>   BASED ON SUPERVISOR_BADGE_NUMBER
      cont>   VALID IF MANAGER_BADGE_NUMBER > 1000.

      In this example, the DEFINE FIELD command bases a second field
      element on the element created in the previous example. The
      VALID IF property explicitly defined for the new element
      overrides the property included in the previous element.

    3.CDO>  DEFINE FIELD SUPERVISOR_SSN
      cont>   BASED ON SSN.

      In this example, the DEFINE FIELD command creates a new element
      from a standard element (SSN). When you use the BASED ON
      property to give different names to field elements that share
      the same properties, you base the new elements on a field
      element that does not change frequently.

    4.CDO>  DEFINE FIELD MANAGER_SSN
      cont>   BASED ON SSN
      cont>   QUERY_HEADER IS "MANAGER SSN".
      CDO>  CHANGE FIELD MANAGER_SSN
      cont>   NOBASED ON.

      In this example, the NOBASED ON keyword removes the BASED ON
      property, but does not remove the QUERY_HEADER property, from
      the MANAGER_SSN field element. Because all other MANAGER_SSN
      properties were based on SSN, you must define new properties
      for MANAGER_SSN, unless the QUERY_HEADER property is adequate.