The CONSTRAIN command moves an uncontrolled element to a base
    partition, the first level of approval. An uncontrolled element
    can be one of the following:

    o  A field, record, or generic element that you created with
       Oracle CDD/Repository Version 4.0 or later

    o  A field, record, or generic element that you created with
       Oracle CDD/Repository, outside a context

    Since fields, records, and generic elements are versioned
    elements, the CONSTRAIN command constrains the highest visible
    version unless you specify another version number.

    Before you issue the CONSTRAIN command, you must create a
    partition and a context for the uncontrolled element and issue
    the SET CONTEXT command to this context.

    The element you are constraining must be a versioned element.
    When you constrain one version of an element, CDO constrains all
    versions of the element.

    An error occurs if you attempt to constrain an element that is
    reserved. The SHOW RESERVATIONS command indicates whether this
    condition exists.

    An error occurs if you attempt to constrain an element that is
    a parent of an uncontrolled element. Constrain the parent and
    children simultaneously by issuing the CONSTRAIN command with the
    /CLOSURE=TO_BOTTOM qualifier.

    After you constrain an element, you issue the ATTACH TO COMPOSITE
    command to explicitly attach the element to a collection, field,
    record, file, or generic element.

                                   NOTE

       The CONSTRAIN command is irreversible. A controlled element
       cannot be changed to an uncontrolled element. All subsequent
       versions of the element are controlled.

    To create subsequent versions, issue the RESERVE command rather
    than the DEFINE command.