composite-element many-to-one not working

chbong · **Joined:** Wed Nov 21, 2007 2:03 am **Posts:** 1

I come across a strange problem where I just can't get it right no matter how I mappped the mapping files to C# class.

I have a following tables:

Code:

CREATE TABLE [dbo].[product](
   [id_product] [int] IDENTITY(1,1) NOT NULL,
   [name] [varchar](max)
)

Code:

CREATE TABLE [dbo].[product_order](
   [id_po] [int] NOT NULL,
   [pk_order] [int] NOT NULL,
   [pk_product] [int] NOT NULL,
   [quantity] [int] NOT NULL
)

Code:

CREATE TABLE [dbo].[order](
   [id_order] [int] IDENTITY(1,1) NOT NULL,
   [description] [varchar](max) NOT NULL
) 

Basically, [product_order] is a many-many table where pk_order and pk_product as the composite keys.

I have the following hbm mapping files for [order]

Code:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="OrderTest" assembly="OrderTest">
  <class name="Order" table="order" lazy="false">
    <id name="id_order" column="id_order" type="System.Int32">
      <generator class="native"/>
    </id>
    <property name="description" column="description" type="System.String"/>
    <set name="ProductOrder" table="product_order" lazy="false" inverse="false">
      <key column="pk_order" />
      <composite-element class="Product">
        <property name="quantity" column="quantity" type="System.Int32"/>
        <many-to-one name="Product" class="Product" column="pk_product" />
      </composite-element>
    </set>
  </class>
</hibernate-mapping>

... and for [product] ...

Code:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="OrderTest" assembly="OrderTest">
  <class name="Product" table="product" lazy="false">
    <id name="id_product" column="id_product" type="System.Int32">
      <generator class="native"/>
    </id>
    <property name="name" column="name" type="System.String"/>
  </class>
</hibernate-mapping>

The corresponded file for c# are

Code:

//------------------------------------------------------------------------------
// <autogenerated>
//     This code was generated by NHibernate.
//
//     Changes to this file may cause incorrect behavior and will be lost if 
//     the code is regenerated.
// </autogenerated>
//------------------------------------------------------------------------------

using System;
using Iesi.Collections;

namespace OrderTest
{
   /// <summary>
   /// POJO for Order. This class is autogenerated
   /// </summary>
   [Serializable]
   public  class Order
   {
      #region Fields
      
      private Int32 _id_order;
      private String _description;
      private Iesi.Collections.ISet productOrder;

      #endregion

      #region Constructors
      
      /// <summary>
      /// Initializes a new instance of the Order class
      /// </summary>
      public Order()
      {
      }
   
      /// <summary>
      /// Initializes a new instance of the Order class
      /// </summary>
      /// <param name="_description">Initial <see cref="Order.description" /> value</param>
      /// <param name="productOrder">Initial <see cref="Order.ProductOrder" /> value</param>
      public Order(String _description, Iesi.Collections.ISet productOrder)
      {
         this._description = _description;
         this.productOrder = productOrder;
      }
   
      /// <summary>
      /// Minimal constructor for class Order
      /// </summary>
      /// <param name="productOrder">Initial <see cref="Order.ProductOrder" /> value</param>
      public Order(Iesi.Collections.ISet productOrder)
      {
         this.productOrder = productOrder;
      }
      #endregion
   
      #region Properties
      
      /// <summary>
      /// Gets or sets the id_order for the current Order
      /// </summary>
      public Int32 id_order
      {
         get { return this._id_order; }
         set { this._id_order = value; }
      }
      
      /// <summary>
      /// Gets or sets the description for the current Order
      /// </summary>
      public String description
      {
         get { return this._description; }
         set { this._description = value; }
      }
      
      /// <summary>
      /// Gets or sets the ProductOrder for the current Order
      /// </summary>
      public Iesi.Collections.ISet ProductOrder
      {
         get { return this.productOrder; }
         set { this.productOrder = value; }
      }
      
      #endregion
   }
}

//------------------------------------------------------------------------------
// <autogenerated>
//     This code was generated by NHibernate.
//
//     Changes to this file may cause incorrect behavior and will be lost if 
//     the code is regenerated.
// </autogenerated>
//------------------------------------------------------------------------------

using System;

namespace OrderTest
{
   /// <summary>
   /// POJO for Product. This class is autogenerated
   /// </summary>
   [Serializable]
   public  class Product
   {
      #region Fields
      
      private Int32 _id_product;
      private String _name;

      #endregion

      #region Constructors
      
      /// <summary>
      /// Initializes a new instance of the Product class
      /// </summary>
      public Product()
      {
      }
   
      /// <summary>
      /// Initializes a new instance of the Product class
      /// </summary>
      /// <param name="_name">Initial <see cref="Product.name" /> value</param>
      public Product(String _name)
      {
         this._name = _name;
      }
   
      #endregion
   
      #region Properties
      
      /// <summary>
      /// Gets or sets the id_product for the current Product
      /// </summary>
      public Int32 id_product
      {
         get { return this._id_product; }
         set { this._id_product = value; }
      }
      
      /// <summary>
      /// Gets or sets the name for the current Product
      /// </summary>
      public String name
      {
         get { return this._name; }
         set { this._name = value; }
      }
      
      #endregion
   }
}

//------------------------------------------------------------------------------
// <autogenerated>
//     This code was generated by NHibernate.
//
//     Changes to this file may cause incorrect behavior and will be lost if 
//     the code is regenerated.
// </autogenerated>
//------------------------------------------------------------------------------

using System;

namespace OrderTest
{
   /// <summary>
   /// POJO for Product. This class is autogenerated
   /// </summary>
   [Serializable]
   public class ProductOrder
   {
      #region Fields
      
      private Int32 _quantity;
      private Product product;

      #endregion

      #region Constructors
      
      /// <summary>
      /// Initializes a new instance of the Product class
      /// </summary>
      public ProductOrder()
      {
      }
   
      /// <summary>
      /// Initializes a new instance of the Product class
      /// </summary>
      /// <param name="_quantity">Initial <see cref="Product.quantity" /> value</param>
      /// <param name="product">Initial <see cref="Product.Product" /> value</param>
      public ProductOrder(Int32 _quantity, Product product)
      {
         this._quantity = _quantity;
         this.product = product;
      }
   
      #endregion
   
      #region Properties
      
      /// <summary>
      /// Gets or sets the quantity for the current Product
      /// </summary>
      public Int32 quantity
      {
         get { return this._quantity; }
         set { this._quantity = value; }
      }
      
      public Product Product
      {
         get { return this.product; }
         set { this.product = value; }
      }
      
      #endregion
   }
}

I have no problem building the project, but Vs2005 makes noise when I try to run it:

Could not find a setter for property 'quantity' in class 'OrderTest.Product' at NHibernate.Property.BasicPropertyAccessor.GetSetter(Type type, String propertyName) at NHibernate.Mapping.Property.GetSetter(Type clazz) at NHibernate.Cfg.HbmBinder.BindComponent(XmlNode node, Component model, Type reflectedClass, String className, String path, Boolean isNullable, Mappings mappings) at NHibernate.Cfg.HbmBinder.BindCollectionSecondPass(XmlNode node, Collection model, IDictionary persistentClasses, Mappings mappings) at NHibernate.Cfg.HbmBinder.BindSetSecondPass(XmlNode node, Set model, IDictionary persistentClasses, Mappings mappings) at NHibernate.Cfg.HbmBinder.SetSecondPass.SecondPass(IDictionary persistentClasses) at NHibernate.Cfg.CollectionSecondPass.DoSecondPass(IDictionary persistentClasses) at NHibernate.Cfg.Configuration.SecondPassCompile() at NHibernate.Cfg.Configuration.BuildSessionFactory() at OrderTest._Default.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\Bong\My Documents\Visual Studio 2005\Projects\OrderTest\Default.aspx.cs:line 29

I wonder what was wrong with my code and mapping? I have been trying for 2 days with any success.

BTW, I use nhibernate 1.2.0.GA and MS SQL2005
Thank in advance.

karlchu · **Posted:** Wed Nov 21, 2007 10:56 am

NHibernate cannot find the property "quantity" in the "Product" class. You need another class that plays the role of an association class for the <set> you have mapped in the Order class. In NHibernate, you cannot add any extra information to a many-to-many association (such as quantity in your case). What you need are two many-to-one associations with the association class in between. The "quantity" would hang off this association class.

marcal · **Posted:** Wed Nov 21, 2007 11:19 am

Well, that's what ProductOrder is doing, but the mapping is incorrect. The <composite-element> class should be ProductOrder, not Product:

Code:

      <composite-element class="ProductOrder">
        <property name="quantity" column="quantity" type="System.Int32"/>
        <many-to-one name="Product" class="Product" column="pk_product" />
      </composite-element>

HTH!