EF6 Code First - 使用不匹配的外鍵配置一對一關係

Question

我使用Code First來定義現有數據庫的模式。我遇到的問題是他們在表中的關鍵名稱不完全對齊。這與一對多關係正常工作，因爲我可以使用HasForeignKey()方法，但似乎沒有一對一關係的等價物。我的表定義是：

namespace Data.Mappings { 

    internal class DocumentTypeConfiguration : EntityTypeConfiguration<Document> { 

     public DocumentTypeConfiguration() { 
      ToTable("ProsDocs"); 

      HasKey(m => m.Id); 

      Property(m => m.Id) 
       .HasColumnName("ProsDocId") 
       .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity); 

      // ---- This is the foreign key ---- 
      Property(m => m.TypeId) 
       .HasColumnName("ProsDocTypeId") 
       .HasMaxLength(3); 

      HasRequired(d => d.DocType) 
       .WithRequiredDependent(dt => dt.Document); 
       // I need to specify here that the foreign key is named "DocTypeId" and not "DocType_Id" 
     } 
    } 

    internal class DocTypeTypeConfiguration : EntityTypeConfiguration<DocType> { 

     public DocTypeTypeConfiguration() { 
      ToTable("DocType"); 

      HasKey(m => m.Id); 

      // ---- This is the "child" end of the foreign key ---- 
      Property(m => m.Id) 
       .HasColumnName("DocTypeId") 
       .HasMaxLength(4); 

      Property(m => m.FullName) 
       .HasColumnName("DocTypeDesc") 
       .HasMaxLength(255); 

      Property(m => m.Priority) 
       .HasColumnName("DocPriority"); 

      // Or would it be easier to define it here? 
//   HasRequired(m => m.Document) 
//    .WithRequiredDependent(d => d.DocType); 
     } 
    } 
} 

爲了澄清模型中，每個Document有DocType，與Document.ProsDocTypeId --> DocType.Id的外鍵關係。

有沒有一種方法來定義什麼列名是鍵爲一對一的關係？

編輯：我想我的模式不清楚。

dbo.DocType 
----------- 
DocTypeId char(4) (PK) 
DocTypeDesc varchar(255) 

dbo.ProsDocs 
------------ 
ProsDocId int (PK) 
ProsDocTypeId char(4) 

基本上，我需要生成的查詢看起來像這樣：

SELECT 
    [Extent1].[ProsDocId] AS [ProsDocId], 
    [Extent2].[DocTypeId] AS [DocTypeId] 
    FROM [dbo].[ProsDocs] AS [Extent1] 
    LEFT OUTER JOIN [dbo].[DocType] AS [Extent2] ON [Extent1].[ProsDocTypeId] = [Extent2].[DocTypeId] 
    WHERE [Extent1].[ProsId] = @EntityKeyValue1 

而是因爲EF假設我想使用的，而不是一個外鍵的主鍵（dbo.ProsDocs.ProsDocId）（dbo.ProsDocs.DocTypeId） ，它生成的查詢是這樣的：

SELECT 
    [Extent1].[ProsDocId] AS [ProsDocId], 
    [Extent2].[DocTypeId] AS [DocTypeId] 
    FROM [dbo].[ProsDocs] AS [Extent1] 
    LEFT OUTER JOIN [dbo].[DocType] AS [Extent2] ON [Extent1].[ProsDocId] = [Extent2].[ProsDocTypeId] 
    WHERE [Extent1].[ProsId] = @EntityKeyValue1 

的區別就在這裏：

理想的查詢：

LEFT OUTER JOIN [dbo].[DocType] AS [Extent2] ON [Extent1].[ProsDocTypeId] = [Extent2].[DocTypeId] 

目前查詢：

LEFT OUTER JOIN [dbo].[DocType] AS [Extent2] ON [Extent1].[ProsDocId] = [Extent2].[ProsDocTypeId] 

我需要創建dbo.ProsDocs.ProsDocTypeId和dbo.DocType.DocTypeId之間的一個一對一的關係。 EF遇到的問題是，它只想使用主鍵創建關係，而不是使用外鍵。如何指定每個Document只有一個DocType的外鍵列名稱？

Answer 1

如果Document是委託人和DocType是相關的，那麼你要麼需要

• 對Document

  HasRequired(d => d.DocType).WithRequiredPrincipal(dt => dt.Document); 
  

• 此類配置，或者在DocType

  這種配置

  HasRequired(dt => dt.Document).WithRequiredDependent(d => d.DocType); 
  

並刪除TypeId/ProsDocTypeId屬性Document作爲主體不能有外鍵id依賴，除非它不是一個約束，只是一個普通的列。

更新

實體：

public class Document 
{ 
    public string Id { get; set; } 
    // This entity is a principal. It can't have foreign key id to dependent. 
    // public string TypeId { get; set; } 
    public DocType DocType { get; set; } 
} 

的Linq：

db.Documents.Include(d => d.DocType) 

查詢：

SELECT 
    1 AS [C1], 
    [Extent1].[ProsDocId] AS [ProsDocId], 
    [Extent2].[DocTypeId] AS [DocTypeId], 
    FROM [dbo].[ProsDocs] AS [Extent1] 
    LEFT OUTER JOIN [dbo].[DocType] AS [Extent2] ON [Extent1].[ProsDocId] = [Extent2].[DocTypeId] 

更新2

要實現理想的查詢，您需要的關係是一對多關係。一個DocType可以有很多Document。

public class Document 
{ 
    public string Id { get; set; } 
    public string TypeId { get; set; } 
    public DocType DocType { get; set; } 
} 
public class DocType 
{ 
    public string Id { get; set; } 
    public string FullName { get; set; } 
    public string Priority { get; set; } 
    public ICollection<Document> Documents { get; set; } 
} 

Document上的配置。

更改此：

HasRequired(d => d.DocType).WithRequiredDependent(dt => dt.Document); 

分爲：

HasRequired(d => d.DocType).WithMany(dt => dt.Documents).HasForeignKey(d => d.TypeId); 

的Linq：

db.Documents.Include(d => d.DocType) 

查詢：

SELECT 
    1 AS [C1], 
    [Extent1].[ProsDocId] AS [ProsDocId], 
    [Extent1].[ProsDocTypeId] AS [ProsDocTypeId], 
    [Extent2].[DocTypeId] AS [DocTypeId], 
    FROM [dbo].[ProsDocs] AS [Extent1] 
    INNER JOIN [dbo].[DocType] AS [Extent2] ON [Extent1].[ProsDocTypeId] = [Extent2].DocTypeId]