PRIMARY KEY约束'PK_dbo.AmazonProducts“的相关规定。不能在对象中插入重复键 [英] Violation of PRIMARY KEY constraint 'PK_dbo.AmazonProducts'. Cannot insert duplicate key in object

问题描述

我有一个问题，试图挽救这是一个外键父对象的实体。

I have a problem trying to save an entity which is a foreign key to a parent object..

我有一个amazonProduct实体。而这是对amazonProduct像这样一个虚拟的列表中AmazonCompetitivePrice实体：

i have an amazonProduct entity. And an AmazonCompetitivePrice entity which is a virtual list on the amazonProduct like so :

public class AmazonProduct
{
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.None)]
        public virtual int ASIN

        public virtual IList<AmazonProductCompetitivePrice> amazonProductCompetitivePrices = new List<AmazonProductCompetitivePrice>();
}

所以我有一个AmazonProduct这是我从数据库中检索，然后添加一个新AmazonProductCompetitivePrice到amazonProduct。

So i have a AmazonProduct which i retrieve from the database, and then add a new AmazonProductCompetitivePrice to the amazonProduct.

但是当我试图挽救这个，我得到以下错误：

But when i try save this, I get the following error:

PRIMARY KEY约束'PK_dbo.AmazonProducts的相关规定。不能
插入重复的对象'dbo.AmazonProducts'.\r\\\
The声明
键已被终止

Violation of PRIMARY KEY constraint 'PK_dbo.AmazonProducts'. Cannot insert duplicate key in object 'dbo.AmazonProducts'.\r\nThe statement has been terminated

它看起来像它没有意识到，我是AmazonProduct已经在数据库中，它试图挽救一个新的，但主键已经存在！

It looks like its not realising that my AmazonProduct is already in the database, and its trying to save a new one but the primary key already exists!

我用流利的API映射，像这样的外键：

I used the fluent API to map the foreign key like so:

        modelBuilder.Entity<AmazonProduct>()
                    .HasMany(pl => pl.AmazonProductCompetitivePrices)
                    .WithOptional(p => p.AmazonProduct)
                    .Map(c => c.MapKey("ASIN"));

任何人都知道什么是错呢？

Anyone know whats wrong with this?

在此先感谢

编辑：
对象检索：

object retrieval:

 using (var uow = new UnitOfWorkInventory())
            {
                using (var amazRepo = new AmazonProductRepository(uow))
                {
                    return amazRepo.FindByAsin(ASIN);
                }
            }
 public AmazonProduct FindByAsin(string asin)
        {
            return context.AmazonProducts.Include(x => x.AmazonLowestOfferListings).Include(x => x.AmazonMyPrices).Include(x => x.AmazonProductCompetitivePrices).SingleOrDefault(x => x.ASIN == asin);
        }

这让我的AmazonProduct ..然后保存：

That gets me the AmazonProduct.. then the save:

using (var uow = new UnitOfWorkInventory())
{
     using (var amazonRepo = new AmazonProductCompetitivePriceRepository(uow))
     {
          amazonProductCompetitivePrice.AmazonProduct = amazonProduct;
          amazonRepo.InsertOrUpdate(amazonProductCompetitivePrice);
     }
          uow.Commit();
}

  public void InsertOrUpdate(AmazonProductCompetitivePrice amazonProductCompetitivePrice)
    {
        if (amazonProductCompetitivePrice.Id == default(int))
        {
            // New entity
            context.AmazonProductCompetitivePrices.Add(amazonProductCompetitivePrice);
        }
        else
        {
            // Existing entity
            context.Entry(amazonProductCompetitivePrice).State = EntityState.Modified;
        }
    }

这就是一切..并感谢您的帮助！

Thats everything.. and thanks for the help!!

推荐答案

这行：

amazonProductCompetitivePrice.AmazonProduct = amazonProduct;

补充 amazonProduct 实例上下文暗示。因为该实例与上下文的不同的实例检索，当前实例认为，这是新的 AmazonProduct 。你应该重视它，而不是，是这样的：

adds amazonProduct instance to context implicitly. Because that instance was retrieved with different instance of context, current instance thinks, that it is new AmazonProduct. You should attach it instead, something like this:

if (amazonProductCompetitivePrice.AmazonProduct != null && amazonProductCompetitivePrice.AmazonProduct.Id != 0)
{
  context.Entry(amazonProductCompetitivePrice.AmazonProduct).State = EntityState.Unchanged;
}

另一种方法：你可以设置外键属性仅对 amazonProductCompetitivePrice 而不是导航属性。

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