JPA composite key mapping

[Alaneus Kingingestingest]

Hi everybody!

I need help with JPA (Toplink) mapping.

I have 3 classes: Products, ProductsDescription and ProductsDescriptionPK.

Products has 1 ID: products_id
ProductsDescription has 2 IDs: products_id and language_id which is in ProductsDescriptionPK, so ProductsDescription has EmbeddedId: ProductsDescriptionPK.

Since 1 product can have many descriptions in different languages,
I wish to bind @OneToMany Products with ProductsDescription by using
products_id, but I can't figure it out how to do it since ProductsDescription has composite key.
Basically I wish to have Collection<ProductsDescription>
in Products which are bindded with its ProductsDescription. Here are the following classes.

    
@Entity
@Table(name = "products")
@NamedQueries({@NamedQuery(name = "Products.findAll", query = "SELECT p FROM Products p"), @NamedQuery(name = "Products.findByProductsId", query = "SELECT p FROM Products p WHERE p.productsId =    :-P	   roductsId"), @NamedQuery(name = "Products.findByProductsQuantity", query = "SELECT p FROM Products p WHERE p.productsQuantity =    :-P	   roductsQuantity"), @NamedQuery(name = "Products.findByProductsModel", query = "SELECT p FROM Products p WHERE p.productsModel =    :-P	   roductsModel"), @NamedQuery(name = "Products.findByProductsImage", query = "SELECT p FROM Products p WHERE p.productsImage =    :-P	   roductsImage"), @NamedQuery(name = "Products.findByProductsPrice", query = "SELECT p FROM Products p WHERE p.productsPrice =    :-P	   roductsPrice"), @NamedQuery(name = "Products.findByProductsDateAdded", query = "SELECT p FROM Products p WHERE p.productsDateAdded =    :-P	   roductsDateAdded"), @NamedQuery(name = "Products.findByProductsLastModified", query = "SELECT p FROM Products p WHERE p.productsLastModified =    :-P	   roductsLastModified"), @NamedQuery(name = "Products.findByProductsDateAvailable", query = "SELECT p FROM Products p WHERE p.productsDateAvailable =    :-P	   roductsDateAvailable"), @NamedQuery(name = "Products.findByProductsWeight", query = "SELECT p FROM Products p WHERE p.productsWeight =    :-P	   roductsWeight"), @NamedQuery(name = "Products.findByProductsStatus", query = "SELECT p FROM Products p WHERE p.productsStatus =    :-P	   roductsStatus"), @NamedQuery(name = "Products.findByProductsTaxClassId", query = "SELECT p FROM Products p WHERE p.productsTaxClassId =    :-P	   roductsTaxClassId"), @NamedQuery(name = "Products.findByManufacturersId", query = "SELECT p FROM Products p WHERE p.manufacturersId = :manufacturersId"), @NamedQuery(name = "Products.findByProductsOrdered", query = "SELECT p FROM Products p WHERE p.productsOrdered =    :-P	   roductsOrdered")})
public class Products implements Serializable {
    @Transient
    private PropertyChangeSupport changeSupport = new PropertyChangeSupport(this);
    private static final long serialVersionUID = 1L;
   
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "products_id")
    private Integer productsId;
    @Basic(optional = false)
    @Column(name = "products_quantity")
    private int productsQuantity;
    @Column(name = "products_model")
    private String productsModel;
    @Column(name = "products_image")
    private String productsImage;
    @Basic(optional = false)
    @Column(name = "products_price")
    private BigDecimal productsPrice;
    @Basic(optional = false)
    @Column(name = "products_date_added")
    @Temporal(TemporalType.TIMESTAMP)
    private Date productsDateAdded;
    @Column(name = "products_last_modified")
    @Temporal(TemporalType.TIMESTAMP)
    private Date productsLastModified;
    @Column(name = "products_date_available")
    @Temporal(TemporalType.TIMESTAMP)
    private Date productsDateAvailable;
    @Basic(optional = false)
    @Column(name = "products_weight")
    private BigDecimal productsWeight;
    @Basic(optional = false)
    @Column(name = "products_status")
    private boolean productsStatus;
    @Basic(optional = false)
    @Column(name = "products_tax_class_id")
    private int productsTaxClassId;
    @JoinColumn(name = "manufacturers_id")
    @OneToOne
    private Manufacturers manufacturersId;
    @Basic(optional = false)
    @Column(name = "products_ordered")
    private int productsOrdered;    
    ????@OneToMany????????
    ?????bind with ProductsDescription.productsDescriptionPK.products_id???? 
    ????private Collection<ProductsDescription> productsDescription;
...
}
 
@Entity
@Table(name = "products_description")
@NamedQueries({@NamedQuery(name = "ProductsDescription.findAll", query = "SELECT p FROM ProductsDescription p"), @NamedQuery(name = "ProductsDescription.findByProductsId", query = "SELECT p FROM ProductsDescription p WHERE p.productsDescriptionPK.productsId =    :-P	   roductsId"), @NamedQuery(name = "ProductsDescription.findByLanguageId", query = "SELECT p FROM ProductsDescription p WHERE p.productsDescriptionPK.languageId = :languageId"), @NamedQuery(name = "ProductsDescription.findByProductsName", query = "SELECT p FROM ProductsDescription p WHERE p.productsName =    :-P	   roductsName"), @NamedQuery(name = "ProductsDescription.findByProductsUrl", query = "SELECT p FROM ProductsDescription p WHERE p.productsUrl =    :-P	   roductsUrl"), @NamedQuery(name = "ProductsDescription.findByProductsViewed", query = "SELECT p FROM ProductsDescription p WHERE p.productsViewed =    :-P	   roductsViewed")})
public class ProductsDescription implements Serializable {
    private static final long serialVersionUID = 1L;
    @EmbeddedId
    protected ProductsDescriptionPK productsDescriptionPK;
    @Basic(optional = false)
    @Column(name = "products_name")
    private String productsName;
    @Lob
    @Column(name = "products_description")
    private String productsDescription;
    @Column(name = "products_url")
    private String productsUrl;
    @Column(name = "products_viewed")
    private Integer productsViewed;
...
}
 
@Embeddable
public class ProductsDescriptionPK implements Serializable {
    @Basic(optional = false)
    @Column(name = "products_id")
    private int productsId;
    @Basic(optional = false)
    @Column(name = "language_id")
    private int languageId;
...
}

Thanks

[ December 17, 2008: Message edited by: Alaneus Kingingestingest ]
[ December 17, 2008: Message edited by: Alaneus Kingingestingest ]

[Angel Taveras]

Hello Alaneus,

Welcome to javaranch!

The JPA specification doesn't specify a compound primary key with a entity, i don't know with Toplink but with Hibernate Entity Manager you use this

@Embeddable
public class ProductsDescriptionPK implements Serializable { 
 
    @ManyToOne
@JoinColumn(name="products_id",referencedColumnName="productsId",nullable=false)
    private Product product;
 
    @Column(name = "language_id",nullable=false)
    private int languageId;
 
   ...
}
 

Another thing that i wanna suggest, you're overusing annotations. For instance you can use @Basic and @Column but it's not necessary. It's not
necessary because @Column have an attribute nullable to add the not null
constraint to the Column at hand. I think that the annotation configurer
will do it's stuff faster with the least annotations as possible, if of course you can do it with less annotations,

Regards,
[ December 17, 2008: Message edited by: Angel Taveras ]

[Bill Hayes]

I am relatively new to this but have been able to successfully accomplish what you're talking about with my own tables.

In your products class you need this...

@OneToMany(cascade = CascadeType.ALL, mappedBy = "mtmpMembers")
private Collection<ProductsDescription> productsDescriptionCollection;    
...
public Collection<MtmpNotes> getMtmpNotesCollection() {
        return mtmpNotesCollection;
    }
 
public void setMtmpNotesCollection(Collection<MtmpNotes> mtmpNotesCollection) {
        this.mtmpNotesCollection = mtmpNotesCollection;
    }

[Bill Hayes]

I am relatively new to this but have been able to successfully accomplish what you're talking about with my own tables in the past couple of weeks.

In your products class you need something like this...

@OneToMany(cascade = CascadeType.ALL, mappedBy = "products")
private Collection<ProductsDescription> productsDescriptionCollection;    
...
public Collection<ProductsDescription> getProductsDescriptionCollection() {
        return productsDescriptionCollection;
    }
 
public void setProductsDescriptionCollection(Collection<ProductsDescription> productsDescriptionCollection) {
        this.productsDescriptionCollection = productsDescriptionCollection;
    }

In your ProductsDescription class you need something like this...

    
...
@Transient
    private PropertyChangeSupport changeSupport = new PropertyChangeSupport(this);
...
//I'm using the database column name for the join column
@JoinColumn(name = "PRODUCT_ID", referencedColumnName = "PRODUCT_ID", insertable = false, updatable = false)
    @ManyToOne(optional = false)
    private Products products;
...
public Products getProducts() {
        return products;
    }
 
    public void setProducts(Products products) {
        Products oldProducts = this.products;
        this.products = products;
        changeSupport.firePropertyChange("products", oldProducts, products);
    }
...
 

Again, please keep in mind that this is new to me also. What I've done here seems to work, but I can't guarantee that it is 100% correct, is not missing something or does not include something extra. Therefore I hope that someone who has more knowledge can take a look and correct as necessary.

[Angel Taveras]

Hi Bill, you're right about the mapping that you're proposing it will work 100%, but what Alaneus it's trying to achieve it's the same behavior with a composite primary key,