Using reference fields as part of entity key with EF 4.1

I am building my data layer using Entity Framework and I am trying to put reference fields of an entity into the key of that entity.

Using VS2010, .NET 4开发者_JAVA百科, EF 4.1, CodeFirst approach.

Given all that info please consider the following code sample:

public class Customer
{
    [Key]
    [Column(Order = 0)]
    public int SetID { get; set; }
    [Key]
    [Column(Order = 1)]
    public int CustomerId { get; set; }
    public string CustomerName { get; set; }
}

public class Product
{
    [Key]
    [Column(Order = 0)]
    public int SetID { get; set; }
    [Key]
    [Column(Order = 1)]
    public int ProductId { get; set; }
    public string ProductName { get; set; }
} 

public class SalesVolume
{
    [Key]
    [Column(Order = 0)]
    public Product product { get; set; }
    [Key]
    [Column(Order = 1)]
    public Customer customer { get; set; }
    [Key]
    [Column(Order = 2)]
    public DateTime SalesDate { get; set; }
    public double Value { get; set; }
}

All my data is organized in sets, so Product and Customer entities have setID fields in them.

For SalesVolume, I have references to Product and Customer entities and I want those reference fields to be a part of my composite primary key for SalesVolume. Quite different from what I am asking, for the code above, EF generated the following table:

CREATE TABLE [dbo].[SalesVolumes](
    [SalesDate] [datetime] NOT NULL,
    [Value] [float] NOT NULL,
    [product_SetID] [int] NULL,
    [product_ProductId] [int] NULL,
    [customer_SetID] [int] NULL,
    [customer_CustomerId] [int] NULL,
PRIMARY KEY CLUSTERED 
(
    [SalesDate] ASC
)

Product and Customer references are placed with two fields each and they are not part of the primary key.

How can I tell EF to generate the SalesVolume table with only one setID field and with PK: (setID, productID, customerID)?

Thanks.

---

You actually just need to declare the foreign key relationship:

public class Customer
{
    [Key]
    [Column(Order = 0)]
    public int SetID { get; set; }
    [Key]
    [Column(Order = 1)]
    public int CustomerId { get; set; }
    public string CustomerName { get; set; }

    public virtual ICollection<SalesVolume> SalesVolumes {get; set;}
}

public class Product
{
    [Key]
    [Column(Order = 0)]
    public int SetID { get; set; }
    [Key]
    [Column(Order = 1)]
    public int ProductId { get; set; }
    public string ProductName { get; set; }

    public virtual ICollection<SalesVolume> SalesVolumes {get; set;}
} 

public class SalesVolume
{
    [Key]
    [Column(Order = 0)]
    public Product product { get; set; }
    [Key]
    [Column(Order = 1)]
    public Customer customer { get; set; }
    [Key]
    [Column(Order = 2)]
    public DateTime SalesDate { get; set; }
    public double Value { get; set; }
}