Annotation error with Many-to-Many.

[samwun9988]

Hello,

There is a problem in my HIbernate/JPA annotation here.

In Eclipse, it highlighted the "mappedBy = "productsForRelatedProductId"" and mappedBy = "productsForProductId" both has the following error:

"In attribute 'productsForProductId', the "mapped by" attribute 'productsForRelatedProductId' also maps this attribute.  Every relationship must have an owner."

and

"In attribute 'productsForRelatedProductId', the "mapped by" attribute 'productsForProductId' also maps this attribute.  Every relationship must have an owner."

Here is the table schema:

CREATE TABLE IF NOT EXISTS

related_product (

product_id int unsigned not null,

related_product_id int unsigned not null,

PRIMARY KEY(product_id, related_product_id),

FOREIGN KEY(product_id) REFERENCES product(product_id),

FOREIGN KEY(related_product_id) REFERENCES product(product_id)

) TYPE=INNODB;

Here is the code:

@ManyToMany(fetch = FetchType.LAZY, mappedBy = "productsForRelatedProductId")

          public Set<Product> getProductsForProductId() {

                    return this.productsForProductId;

          }

          @ManyToMany(fetch = FetchType.LAZY, mappedBy = "productsForProductId")

          public Set<Product> getProductsForRelatedProductId() {

                    return this.productsForRelatedProductId;

          }

Very appreciate for any suggestion and help.

Thanks

Sam

[wdfink]

I suppose that only the leading attribute should have the 'mappedBy' attribute.

[samwun9988]

Thank you very much for the suggestion.

The database design had a little issue with many-to-many relationship.

After removed the Foreign Key on the table, made it becomes one-to-many relationship, and re-generate the codes, problem is gone.

Thanks

Sam