Question

我有2个人：

@Entity
@Table(name="product")
public class Product {
    private Long id;
    private Set<Upgrade> upgrade;

    @Id
    @Column(name="id")
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @ManyToMany(mappedBy = "products",
                targetEntity = Upgrade.class,
                cascade = CascadeType.REFRESH,
                fetch = FetchType.EAGER)
    public Set<Upgrade> getUpgrade() {
        return upgrade;
    }

    public void setUpgrade(Set<Upgrade> upgrade) {
        this.upgrade = upgrade;
    }
}

和

@Entity
@Table(name="upgrade")
public class Upgrade {
    private Long id;
    private Set<Product> products;

    @Id
    @Column(name="id")
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @ManyToMany(targetEntity = Product.class, cascade = CascadeType.REFRESH, fetch = FetchType.EAGER)
    @JoinTable(name = "upgrade_product",
               joinColumns = @JoinColumn(name = "upgrade_id"),
               inverseJoinColumns = @JoinColumn(name="product_id"))
    public Set<Product> getProducts() {
        return products;
    }

    public void setProducts(Set<Product> products) {
        this.products = products;
    }
}

我的数据会创建这些数据，以便产品包含一组多个升级。

即。 P1 {U1，U2，U3，U4} P2 {U1，U3，U5，U7}

如果我删除升级，那么一切都很好。它刚刚从产品中删除。但是，如果我删除了某个产品，那么它会尝试删除所有链接的升级。

如何让它能够删除产品并保留升级。

Answer 1

在删除Product之前，请清除其Set<Upgrade>并保存Product。类似的东西：

public void delete(Product p)
{
    p.setUpgrade(Collections.emptySet());
    entityManager.remove(entityManager.merge(p));
}

Hibernate - 删除链接的实体

1 个答案: