ManyToOne relationship with extra field in the joinTable

Question

Hi,
I wanted to make a ManyToMany unidirectional relationship using these two entities.
Invoice (id)
Product (id, price)
The problem is that I want in the resulting joinTable another field named QUANTITY
I don’t think there is a way to obtain a join table with an extra field from a ManyToMany relationship, am I right ?
Si I decided to add an InvoiceLine table
With Invoice and InvoiceLine tables having a OneToMany unidirectional relationship.
And InvoiceLine and Product tables having a ManyToOne unidirectional relationship.
This is the code I made
import java.util.Set;
import java.util.HashSet;
import javax.persistence.*;
@Entity
public class Invoice implements java.io.Serializable {
     private long id;
     private Set<InvoiceLine> InvoiceLines = new HashSet<InvoiceLine>();
     @Id
     @GeneratedValue
     public long getId() {
          return id;
     public void setId(long id) {
          this.id = id;
     @OneToMany(cascade={CascadeType.ALL})
     @JoinColumn(name="INVOICE_ID")
     public Set<InvoiceLine> getInvoiceLines() {
          return InvoiceLines;
     public void setInvoiceLines(Set<InvoiceLine> InvoiceLines) {
          this.InvoiceLines = InvoiceLines;
import javax.persistence.*;
@Entity
public class InvoiceLine implements java.io.Serializable {
     private long id;
     private Product product;
     private int quantity;
     @Id
     @GeneratedValue
     public long getId() {
          return id;
     public void setId(long id) {
          this.id = id;
     @ManyToOne
     public Product getProduct() {
          return product;
     public void setProduct(Product product) {
          this.product = product;
     public int getQuantity() {
          return quantity;
     public void setQuantity(int quantity) {
          this.quantity = quantity;
import javax.persistence.*;
@Entity
public class Product implements java.io.Serializable {
     private long id;
     private double price;
     public Product() {
     public Product(double price) {
          this.price = price;
     @Id
     @GeneratedValue
     public long getId() {
          return id;
     public void setId(long id) {
          this.id = id;
     public double getPrice() {
          return price;
     public void setPrice(double price) {
          this.price = price;
}The problem is that I want the InvoiceLine table to have a composite primary key (from the two foreign keys in the table invoice_id and product_id).
Can anyone tell me how I can do this.
Thanks.
Edited by: Exhortae on Jun 23, 2009 4:59 PM
Edited by: Exhortae on Jun 23, 2009 5:01 PM

Answer 1

Hello,
If we create a Z report for this program, can anyone please tell me where can I find the function "REUSE_ALV_GRID_DISPLAY" in the given program so that I can add my fields along with the default filelds displayed...
Thanks
~Him