java - manyTomany 会出现性能问题吗？

Question

我有这样的代码

   public Serializable save(Product product) {
    product.getCategories().forEach(category -> category.getProducts().add(product));

    return super.save(product);
   }

Category 会有很多产品，hibernate 会全部加载吗？

如果是，如何在 dao 或实体级别解决此问题？

@Table//...
public class Product {//...
@Cascade(value = SAVE_UPDATE)
@ManyToMany(mappedBy = "products", fetch = FetchType.LAZY, targetEntity = Category.class)
private Set<Category> categories = new HashSet<>();

}

@Table//...
public class Category {//... 
@Cascade(value = SAVE_UPDATE)
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "productToCategory",
        joinColumns = {@JoinColumn(name = "categoryId")},
        inverseJoinColumns = {@JoinColumn(name = "productId")})
private Set<Product> products = new HashSet<>();
}

标签： javasqldatabasehibernateorm

Answer 1

这是我的问题的答案：

邮政