在 NHibernate 中不是持久性 M:N 与关联 class？

Question

我想映射一个 M:N 产品和购物车之间的关联，以及它们之间的关联 class ProductsOfCart。但是数据不是持久性的，但我不知道你为什么能帮我？

Here is a code from CartControler

Create();

Product productD = new ProductDao().GetById(product);

ProductsOfCart productsOfCart = new ProductsOfCart();

User user = new UserDao().GetByLogin(User.Identity.Name);

Cart cart = new CartDao().GetByUser(user);

cart.Price += productD.Price;
cart.PriceDph += productD.PriceDph;
cart.NumberOfItems++;

ProductsOfCartDao productsOfCartDao = new ProductsOfCartDao();

CartDao cartDao = new CartDao();

CartDao.Update(cart);

productsOfCart.IdCart = cart;

productsOfCart.IdCart = productD;

productsOfCartDao.Create(productsOfCart);

Cart, Product and ProductsOfCart

public class Cart :IEntity
{

    public virtual int Id { get; set; }

    public virtual double Price { get; set; }

    public virtual double PriceDph { get; set; }

    public virtual int NumberOfItems { get; set; }

    public virtual User IdUser { get; set; }

    public virtual IList<Product> Products { get; set; }  
}

public class Product : IEntity
{

    public virtual int Id { get; set; }

    public virtual string Name { get; set; }

    public virtual int Price { get; set; }

    public virtual string ProductState { get; set; }

    public virtual string Maker { get; set; }

    public virtual string Description { get; set; }

    public virtual int ProductWaranty { get; set; }

    public virtual ProductCategory Category { get; set; }

    public virtual string ImageName { get; set; }

    public virtual IList<Cart> Carts { get; set; }
}

public class ProductsOfCart : IEntity
{
    public virtual int Id { get; set; }

    public virtual Product IdProduct { get; set; }

    public virtual Cart IdCart { get; set; }

}

And here are XML files of Product, Cart and ProductsOfCart

<class name="Product" table="Products">
    <id name="Id" column="id_product">
      <generator class="native" />
    </id>
    <property name="Name" column="name" />
    <property name="Price" column="price" />
    <property name="ProductState" column="productState" />
    <property name="Maker" column="maker" />
    <property name="Description" column="description" />
    <property name="ProductWaranty" column="productWaranty" />
    <many-to-one name="Category" column="id_category" foreign-key="id_category" />
    <property name="ImageName" column="imageName" />
<bag name="Carts" lazy="true"
   inverse="true" batch-size="25" cascade="all-delete-orphan">
  <key column="id_product" />
  <one-to-many class="ProductsOfCart" />
</bag>

</class>

<class name="Cart" table="Carts">
    <id name="Id" column="id_cart">
      <generator class="native" />
    </id>
    <property name="Price" column="price" />
    <property name="PriceDph" column="priceDph" />
    <property name="NumberOfItems" column="numberOfItems" />
    <many-to-one name="IdUser" column="id_User" foreign-key="id_User" />
  <bag name="Products" lazy="true" 
   inverse="true" batch-size="25" cascade="all-delete-orphan">
  <key column="id_cart" />
  <one-to-many class="ProductsOfCart" />
</bag>
</class>

<class name="ProductsOfCart" table="ProductsOfCart">
    <id name="Id" column="id_ProductsOfCart">
      <generator class="native" />
    </id>
    <many-to-one name="IdProduct" column="id_product" foreign-key="id_product"/>
    <many-to-one name="IdCart" column="id_cart" foreign-key="id_cart" />
</class>

Answer 1

如果我们想将配对对象创建为实体。我们需要这样的映射：

<class name="Product" table="Products">
    ... // as is    
    <bag name="Categories" lazy="true" 
       inverse="true" batch-size="25" cascade="all-delete-orphan">
      <key column="id_product" />
      <one-to-many class="ProductsOfCart" />
    </bag>

</class>

<class name="Cart" table="Carts">
    ... // as is    
    <bag name="Products" lazy="true" 
       inverse="true" batch-size="25" cascade="all-delete-orphan">
      <key column="id_cart" />
      <one-to-many class="ProductsOfCart" />
    </bag>
</class>


<class name="ProductsOfCart" table="ProductsOfCart">
    <many-to-one name="Product" column="id_product" />
    <many-to-one name="Cart" column="id_cart"  />
</class>

我们的类看起来像：

public class Cart :IEntity
{
    ...
    public virtual ILIst<ProductCategory> Products { get; set; }   
}

public class Product : IEntity
{
    ...
    public virtual IList<ProductCategory> Categories { get; set; }
}

public class ProductCategory : IEntity
{
    ...
    public virtual Product Product{ get; set; }
    public virtual Category Category { get; set; }
}

我更喜欢这种结构。在它之上创建复杂的查询很容易...尝试在此处阅读更多示例 many-to-many with extra columns nhibernate

但我们也可以隐藏配对 table，并使用映射 many-to-many，这将完全隐藏配对 table 和配对C# 对象

<class name="Product" table="Products">
    ... // as is    
    <bag name="Categories" lazy="true" 
       table="ProductsOfCart" // many-to-many requires table defintion
       inverse="true" batch-size="25"
       cascade="none"> // cascade would not effect the pair, but Category
                       // usually not wanted
      <key column="id_product" />
      <many-to-many class="Category" column="id_product" />
    </bag>

</class>

<class name="Cart" table="Carts">
    ... // as is    
    <bag name="Products" lazy="true" table="ProductsOfCart"
       inverse="false"  // one side MIGHT NOT be inverse
       batch-size="25" 
       cascade="none"> // cascade would not effect the pair, but Product
                      // usually not wanted
      <key column="id_cart" />
      <many-to-many class="Product" column="id_product" />
    </bag>
</class>

我们的类看起来像：

public class Cart :IEntity
{
    ...
    public virtual IList<Product> Products { get; set; }   
}

public class Product : IEntity
{
    ...
    public virtual IList<Category> Categories { get; set; }
}

在这里阅读关于多对多的内容

延长

如果您没有提供 persiter... 例外情况请确保：

所有 hbm 映射文件确实具有后缀 .hbm.xml（检查任何拼写错误）
所有 hbm 映射文件必须是 Embedded resources
配置必须包含 (more here):

NH 会话工厂配置

    ...
    <mapping assembly="Project.DomainModel"/>  <!-- Here -->
</session-factory>

另外，问题中的最新映射是正确的——而 C# 的东西不是。要拥有此集合映射：

(Product.hbm.xml)

...
<bag name="Carts" lazy="true"
   inverse="true" batch-size="25" cascade="all-delete-orphan">
  <key column="id_product" />
  <one-to-many class="ProductsOfCart" />
</bag>

C# POCO 必须是：

public class Product : IEntity
{
    ...
    // instead of this
    // public virtual IList<Cart> Carts { get; set; }
    // we need this
    public virtual IList<ProductsOfCart> Carts { get; set; }
}

这些信息应该足够运行，我会说

在 NHibernate 中不是持久性 M:N 与关联 class？

Not persister M:N with association class in NHibernate?

.net

nhibernate

nhibernate-mapping