主外键的JPA-Hibernate映射

Question

I have a little problem with JPA mapping. I want do this:

I have a table 'sale', and it has a id ( ven_cod ).

And i have a table 'credit_sale', its pk shall be a sales pk that means some sales can be credit_sale.

For instance, i have 2 sales, with code 01 and 02. The second one is a credit_sale, than in the table 'credit_sales' i'll have a register with pk 02.

How can i map this with jpa-hibernate ?? i tried this, but didn't work:

@Entity
@Table(name = "venda_credito")
public class VendaCredito {

    private long cod;
    private Cliente cliente;
    private StatusPagamento statusPagamento;
    private Date dataPagamento;

    @Id
    @JoinColumn(name = "ven_cod")
    @OneToOne
    public long getCod() {
        return cod;
    }

    .
    .
    .

@Entity
@Table(name = "venda")
public class Venda  {

    private long cod;


    @Id
    @GeneratedValue
    @Column(name = "ven_cod")
    public long getCod() {
        return cod;
    }

    .
    .
    .

What must i do to this work ?

Answer 1

You can use a derived identity.

Change VendaCredito to look like this:

@Entity
@Table(name = "venda_credito")
public class VendaCredito {

    private long cod;
    private Venda venda;
    private Cliente cliente;
    private StatusPagamento statusPagamento;
    private Date dataPagamento;

    @Id
    public long getCod() {
        return cod;
    }

    @MapsId
    @JoinColumn(name = "ven_cod")
    @OneToOne
    public long getCod() {
        return cod;
    }
    .
    .
    .

This is discussed in the JPA 2.1 spec section 2.4.1.3 ex. 4.