A dependency case in Isis

[L Eder]

Hello members

i have this use case, in that i need to extract some data from a
repository object of the own entity.

Let me explain:
In the creation of a new entity Scenario, i have to select a past
scenario, via drop-down list of Scenario repository.

Then i did this: i added a reference property to itself
Scenario,.java:
    private Scenario pastScenario;

However i am getting this IDE build time error:

MySQLIntegrityConstraintViolationException: Cannot add or update a
child row: a foreign key constraint fails (`database`.`#sql-6c4_44c`,
CONSTRAINT `scenario_fk1` FOREIGN KEY (`pastscenario_id_oid`)
REFERENCES `scenario` (`id`))

How could then correctly model this dependency case in Isis?

Thanks for any help, Eder
-------------------------------------
Scenario.java
"
....
    @Column(allowsNull = "true")
    @Property()
    @Getter @Setter
    private Scenario pastScenario;

     ...

    @Persistent(table="ScenarioStuffItems")
    @Join(column="scenario_id")
    @Element(column="stuffitem_id")
    @Getter @Setter
    @CollectionLayout(render = RenderType.EAGERLY, named="Stuff View")
    private SortedSet<StuffItem> stuffItems = new TreeSet<StuffItem>();

   ....

   public Scenario importStuff() {

   final SortedSet<StuffItem> stuffItemsOnPastScenario =
this.getPastScenario().getStuffItems();

   for (StuffItem siOnPS: stuffItemsOnPastScenario){...extract some data ...}

   ....

   }
"

ScenarioMenu.java
"
    @Action(
    )
    @MemberOrder(sequence = "3")
    public Scenario create(
    ...
    @Parameter(optionality = Optionality.OPTIONAL)
    @ParameterLayout(named="Past Scenario")
    final Scenario pastScenario,
    ....
"