Join table with additional data

Question

Hi,
I'm new to JPA (Toplink Essentials) and I'd like to know how to handle this situation:
I have ORDER table, ITEMS table and "join table" ORDER_ITEMS which holds refernces to ordered items with quantity of each oredered item.
Many thanks

Answer 1

I did mapping as shown in listing. It works for reading, but for writing JPA returns error. Can somebody help?
Thanks
[Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]Column name 'idexpedice' appears more than once in the result column list.
Error Code: 264
Call: INSERT INTO vklad_expedice (IDEXPEDICE, IDVKLAD, VAHA, idexpedice, idvklad) VALUES (?, ?, ?, ?, ?)
bind => [null, null, 0, 4411, 2]
@Entity
public class Expedice implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer idexpedice;
@Temporal(TemporalType.DATE)
private Date datum;
@OneToMany(fetch = FetchType.EAGER, mappedBy="expedice", cascade = CascadeType.ALL)
private List<ExpediceVklad> vklady;
@Entity
public class Vklad implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer idvklad;
private String nazev;
@Entity
@Table(name = "vklad_expedice")
@IdClass(ExpediceVkladId.class)
public class ExpediceVklad implements Serializable {
@Id
private Integer idexpedice;
@Id
private Integer idvklad;
private Integer vaha;
@ManyToOne
@JoinColumn(name = "idexpedice")
private Expedice expedice;
@ManyToOne
@JoinColumn(name = "idvklad")
private Vklad vklad;
public class ExpediceVkladId {
@Id
private Integer idexpedice;
@Id
private Integer idvklad;
SQL tables
EXPEDICE
idexpedice
datum
VKLAD
idvklad
nazev
VKLAD_EXPEDICE (this is the join table with additional column)
idexpedice
idvklad
vaha
Edited by: user10933983 on 31.3.2009 13:47