1 回答

TA貢獻1827條經驗 獲得超9個贊
您需要的是多對多關系,而不是單對多關系。與 JoinTable 一起映射產品和類別之間的關系。
@Entity
public class Product {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int product_id;
private String naam;
private String omschrijving;
private double prijs;
@OneToMany(mappedBy = "product_m")
private List<Aanbieding> aanbiedingen;
@ManyToMany(cascade = { CascadeType.ALL })
@JoinTable(
name = "product_categories",
joinColumns = { @JoinColumn(name = "product_id") },
inverseJoinColumns = { @JoinColumn(name = "categorie_id") }
)
private List<Categorie> categories;
}
@Entity
public class Categorie {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int categorie_id;
private String naam;
private String omschrijving;
@ManyToMany(mappedBy = "categories")
private List<Product> producten;
}
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