[GUSDEV] na_sequence_id isn't the primary key of DoTS.NaSequence?

[Aaron J. M. <am...@pc...>]

FOREIGN KEY (a_na_sequence_id) REFERENCES DoTS.NaSequence  
(na_sequence_id),
                                                             *
ERROR at line 22:
ORA-02270: no matching unique or primary key for this column-list


Does NASequence have a composite primary key with (na_sequence_id,  
version) ?  How then do NAfeature's enforce constraints without  
including version?

-Aaron