NHibernate：使用Fluent Nhibernate保存子对象 [英] NHibernate: Using Fluent Nhibernate to save child objects

问题描述

在我的系统中，我有两个实体 - ShoppingCart和ShoppingCartItem。相当通用的用例。但是，当我保存我的ShoppingCart时，没有任何项目被保存到数据库。

在我的对象中创建一个新的ShoppingCart对象。
$ b

  ShoppingCart cart = CreateOrGetCart（）; 
  

然后我从数据库中添加一个现有的产品到开始。

  cart.AddItem（product）; 
  

这只是一个将项目添加到IList的简单包装。 b

  public virtual void AddItem（Product product）
 {
 Items.Add（new ShoppingCartItem {Quantity = 1，Product = product}） ; 
} 
  

然后在Repository上调用SaveOrUpdate

  Repository.SaveOrUpdate（cart）; 
  

看起来像这样：

{
Session.SaveOrUpdate（entity）;
返回实体;



$ b我使用Fluent NHibernate进行映射：

  public ShoppingCartItemMap（）
 {
 WithTable（ShoppingCartItems）; 
 
 Id（x => x.ID，ShoppingCartItemId）; 
 Map（x => x.Quantity）; 
 
参考（x => x.Cart，ShoppingCartId）。Cascade.SaveUpdate（）; 
参考文献（x => x.Product，ProductId）; 
 
 
 $ b public ShoppingCartMap（）
 {
 WithTable（ShoppingCarts）; 
 
 Id（x => x.ID，ShoppingCartId）; 
 Map（x => x.Created）; 
 Map（x => x.Username）; 
 
 HasMany< ShoppingCartItem>（x => x.Items）
 .IsInverse（）。Cascade.SaveUpdate（）
 .WithKeyColumn（ShoppingCartId）
 .AsBag（）;数据库模式（SQL Server 2005）也相当通用：
 
 $ b $ pre $ code CREATE TABLE [dbo]。[ShoppingCarts] 
（
 [ShoppingCartID] [int] NOT NULL IDENTITY（1， 1），
 [用户名] [nvarchar]（50）NOT NULL，
 [创建] [日期时间] NOT NULL 
）
 GO 
 ALTER TABLE [dbo] 。[ShoppingCarts] ADD CONSTRAINT [PK_ShoppingCarts] PRIMARY KEY CLUSTERED（[ShoppingCartID]）
 GO 
 
 
 
 CREATE TABLE [dbo]。[ShoppingCartItems] 
（
 [ShoppingCartItemId] [int]不是NULL IDENTITY（1,1），
 [ShoppingCartId] [int]不是NULL，
 [ProductId] [int] NOT NULL，
 [Quantity] [int] NOT NULL 
）
 GO 
 ALTER TABLE [dbo]。[ShoppingCartItems] ADD CONSTRAINT [PK_ShoppingCartItems] PRIMARY KEY CLUSTERED（[ShoppingCartItemId]）
 GO 
 ALTER TABLE [dbo]。[ShoppingCartItems] ADD CONSTRAINT [FK_ShoppingCartItems_Products] FOREIGN KEY（[ProductId]）REFERENCES [dbo]。[Products]（[ProductId]）
 GO 
 ALTER TABLE [ [ShoppingCartId]] [ShoppingCartItems] ADD CONSTRAINT [FK_ShoppingCartItems_ShoppingCarts] FOREIGN KEY（[ShoppingCartId]）REFERENCES [dbo]。[ShoppingCarts]（[ShoppingCartID]）
 GO 
  

当我SaveOrUpdate我的ShoppingCart时，为什么没有任何ShoppingCartItems也被保存？

请帮忙。

谢谢

更新：
在交易中包装它提供了更多信息：

lockquote

无法将值NULL插入'ShoppingCartId'列，表
'WroxPizza.dbo.ShoppingCartItems';列不允许空值。
INSERT失败。该语句已被终止。

这是因为它是一个新的购物车。

解决方案

我对流利的nhibernate有这个确切的问题。映射一对多关系似乎存在一个小错误，并且关系不会自动保存或级联。 请在这里查看关于它在Fluent NHibernate组上发表的帖子 。

显然，有人正在处理这个问题！

我可以肯定地说这个是您的代码的问题，但它看起来非常相似，我有一个问题。希望有所帮助！

In my system, I have two entities - ShoppingCart and ShoppingCartItem. Fairly generic use-case. However, when I save my ShoppingCart, none of the items are being saved to the DB.

Within my object, I create a new ShoppingCart object.

ShoppingCart cart = CreateOrGetCart();

I then add an existing Product which I got from the database to the start.

cart.AddItem(product);

This is just a simple wrapper to add the item to the IList.

    public virtual void AddItem(Product product)
    {
        Items.Add(new ShoppingCartItem { Quantity = 1, Product = product });
    }

I then call SaveOrUpdate on the Repository

Repository.SaveOrUpdate(cart);

Which looks like this:

   public T SaveOrUpdate(T entity)
    {
        Session.SaveOrUpdate(entity);
        return entity;
    }

I'm using Fluent NHibernate for the mapping:

    public ShoppingCartItemMap()
    {
        WithTable("ShoppingCartItems");

        Id(x => x.ID, "ShoppingCartItemId");
        Map(x => x.Quantity);

        References(x => x.Cart, "ShoppingCartId").Cascade.SaveUpdate();
        References(x => x.Product, "ProductId");
    }


    public ShoppingCartMap()
    {
        WithTable("ShoppingCarts");

        Id(x => x.ID, "ShoppingCartId");
        Map(x => x.Created);
        Map(x => x.Username);

        HasMany<ShoppingCartItem>(x => x.Items)
            .IsInverse().Cascade.SaveUpdate()
            .WithKeyColumn("ShoppingCartId")
            .AsBag();
    }

Database Schema (SQL Server 2005) is also fairly generic:

CREATE TABLE [dbo].[ShoppingCarts]
(
[ShoppingCartID] [int] NOT NULL IDENTITY(1, 1),
[Username] [nvarchar] (50) NOT NULL,
[Created] [datetime] NOT NULL
)
GO
ALTER TABLE [dbo].[ShoppingCarts] ADD CONSTRAINT [PK_ShoppingCarts] PRIMARY KEY CLUSTERED ([ShoppingCartID])
GO



CREATE TABLE [dbo].[ShoppingCartItems]
(
[ShoppingCartItemId] [int] NOT NULL IDENTITY(1, 1),
[ShoppingCartId] [int] NOT NULL,
[ProductId] [int] NOT NULL,
[Quantity] [int] NOT NULL
)
GO
ALTER TABLE [dbo].[ShoppingCartItems] ADD CONSTRAINT [PK_ShoppingCartItems] PRIMARY KEY CLUSTERED ([ShoppingCartItemId])
GO
ALTER TABLE [dbo].[ShoppingCartItems] ADD CONSTRAINT [FK_ShoppingCartItems_Products] FOREIGN KEY ([ProductId]) REFERENCES [dbo].[Products] ([ProductId])
GO
ALTER TABLE [dbo].[ShoppingCartItems] ADD CONSTRAINT [FK_ShoppingCartItems_ShoppingCarts] FOREIGN KEY ([ShoppingCartId]) REFERENCES [dbo].[ShoppingCarts] ([ShoppingCartID])
GO

When I SaveOrUpdate my ShoppingCart, why isn't any ShoppingCartItems also being saved?

Please help.

Thanks

Ben

UPDATE: Wrapping it in a transaction providng me with some more info:

Cannot insert the value NULL into column 'ShoppingCartId', table 'WroxPizza.dbo.ShoppingCartItems'; column does not allow nulls. INSERT fails. The statement has been terminated.

This is because it's a new cart.

解决方案

I had this exact problem with fluent nhibernate. There appears to be a small bug in mapping one-to-many relationships and the relationships not automatically saving or cascading. See here for a posting about it on the Fluent NHibernate group.

Apparently, there is someone working on the issue!

I can;t say for sure that this is the issue with your code but it looks very similar to a problem I had. Hope that helps some!

这篇关于NHibernate：使用Fluent Nhibernate保存子对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！