在同一个类中映射两个引用，但引用类具有复合键 [英] Mapping two references in the same class but reference class has Composite key

问题描述

我有以下的数据库表（为了清楚起见，这些都缩写了）：

$ $ $ $ $ codeREATE TABLE [dbo]。[prod_uom] （
[prod_id] [dbo]。[uid] NOT NULL， - 主键
[uom_type] [数字]（9，0）非NULL， - 主键
）

CREATE TABLE [dbo]。[order_line]（
[order_line_id] [dbo]。[uid] NOT NULL，--Primary key
[prod_id] [dbo]。[ uid] NOT NULL， - 外键
[uom_type_requested] [数字]（9，0）NOT NULL， - 外键
[uom_specified] [数字]（9，0）外键





$ b

实体我遇到了这样的问题（缩写）：

  public class OrderLine 
 {
 public virtual Guid OrderLineId {get;私人设置} 
 public virtual ProductUom UomRequested {get;组; } 
 public virtual ProductUom UomSpecified {get;组; } 
} 
 
 public class ProductUom 
 {
 public virtual Guid ProductId {get;私人设置} 
 public virtual decimal UomType {get;组; } b 
 
 
 
 $ p $基本上我有两个对 PROD_UOM 的引用我的 ORDER_LINE 类中的表。我的第一次尝试映射如下：
 
 pre $ public $ Order $ $ 
 $ $ b $ ORDER_LINE）; 
 Id（x => x.OrderLineId，ORDER_LINE_ID）; 
 
引用（x => x.UomSpecified）
 .Columns（new string [] {PROD_ID，UOM_SPECIFIED}）; 
 
引用（x => x.UomRequested）
 .Columns（new string [] {PROD_ID，UOM_TYPE_REQUESTED}）; 
 
 
 
 $ b 
这个映射得到了可怕的错误（PROD_ID被引用两次）：
  System.IndexOutOfRangeException：此Count = 17的SqlParameterCollection的索引17无效。 
  
 
 
 
有没有简单的方法来映射这种关系？
 
 
 
 
 
还有一些其他的选择，但那是我建议的，因为它们可能比这更不雅。
 
I have the following database tables (These are abbreviated for clarity):  
CREATE TABLE [dbo].[prod_uom](
    [prod_id] [dbo].[uid] NOT NULL,       --Primary key
    [uom_type] [numeric](9, 0) NOT NULL,  --Primary Key
)

CREATE TABLE [dbo].[order_line](
    [order_line_id] [dbo].[uid] NOT NULL,  --Primary key
    [prod_id] [dbo].[uid] NOT NULL,        --Foreign key
    [uom_type_requested] [numeric](9, 0) NOT NULL, --Foreign key
    [uom_specified] [numeric](9, 0) NOT NULL        --Foreign key
)
Entity I'm having trouble with looks like this (Abbreviated):
public class OrderLine
{
     public virtual Guid OrderLineId { get; private set; }
     public virtual ProductUom UomRequested { get; set; }
     public virtual ProductUom UomSpecified { get; set; }
}

public class ProductUom
{
    public virtual Guid ProductId { get; private set; }
    public virtual decimal UomType { get; set; }
}
Basically I have 2 References to the PROD_UOM table inside my ORDER_LINE class.  My first attempt at mapping this was the following:  
public OrderLineMap()
{
    Table("ORDER_LINE");
    Id(x => x.OrderLineId, "ORDER_LINE_ID");

    References(x => x.UomSpecified)
        .Columns(new string[] { "PROD_ID", "UOM_SPECIFIED" });

    References(x => x.UomRequested)
        .Columns(new string[] { "PROD_ID", "UOM_TYPE_REQUESTED" });
}
This mapping gets the dreaded error (PROD_ID is referenced twice):  
System.IndexOutOfRangeException: Invalid index 17 for this SqlParameterCollection with Count=17. 


Is there an easy way to map this relationship?
解决方案
I'm fairly certain you can't map the same column twice so my suggestion would be to split the PROD_ID column in ORDER_LINE into two, PROD_ID_SPEC and PROD_ID_REQ.  

There are some other options but that is the one I would suggest as they are probably even more inelegant than that.

                        
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