[eclipselink-users] How to map cyclic foreign key references with not-nu

[janne postilista <jannepostilistat@xxxxxxxxx>]

How do I map the following scenario:

TABLE FOO (
  ID NUMBER(10) PRIMARY KEY NOT NULL,
  BAR_ID NUMBER(10) FOREIGN KEY NOT NULL
);

TABLE BAR (
  ID NUMBER(10) PRIMARY KEY NOT NULL,
  FOO_ID NUMBER(10) FOREIGN KEY NOT NULL
);

ids from sequences SEQ_FOO and SEQ_BAR.

When I try to persist/merge this kind of dual object I always get:

Caused by: org.h2.jdbc.JdbcSQLException: NULL not allowed for column
"BAR_ID"; SQL statement:
INSERT INTO FOO (ID, BAR_ID) VALUES (?, ?) [23502-154]
        at org.h2.message.DbException.getJdbcSQLException(DbException.java:327)
        at org.h2.message.DbException.get(DbException.java:167)
        at org.h2.message.DbException.get(DbException.java:144)
        at org.h2.table.Column.validateConvertUpdateSequence(Column.java:297)
        at org.h2.table.Table.validateConvertUpdateSequence(Table.java:669)

My mappings:

@Entity
@Table(name = "FOO")
public class Foo {

    @Id
    @Column(nullable = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "FOO_GEN")
    @SequenceGenerator(name = "FOO_GEN", sequenceName = "SEQ_FOO",
allocationSize = 1)
    private Long id;

    @OneToOne
    @JoinColumn(name = "BAR_ID")
    private Bar bar;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Bar getBar() {
        return bar;
    }

    public void setBar(Bar bar) {
        this.bar = bar;
    }


}



@Entity
@Table(name = "BAR")
public class Bar {

    @Id
    @Column(nullable = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "BAR_GEN")
    @SequenceGenerator(name = "BAR_GEN", sequenceName = "SEQ_BAR",
allocationSize = 1)
    private Long id;

    @OneToOne
    @JoinColumn(name = "FOO_ID")
    private Foo foo;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Foo getFoo() {
        return foo;
    }

    public void setFoo(Foo foo) {
        this.foo = foo;
    }

}

I get the same result using ManyToOne relationships. I have also tried
a combination with Foo having ManyToOne Bar and Bar having OneToOne
Foo.

Actual relationships are a) unidirectional 1:n mapping and b)
unidirectional 1:1 mapping.
- n Foo objects all point to same Bar. Bar does not need to know the
collection of n Foo objects pointing to it
- each Bar points to a single Foo.