代碼在連接表中的第一流利的API和導航屬性

Question

我有四個實體，我想通過代碼第一流利的API（我使用在databaseanswers.org找到的模型）轉換成數據庫表，但我不確定如何。我遇到的問題是SuggestedMenuId正在通過Composite鍵（MenuCourse和CourseRecipeChoice）中的兩個不同表遷移。

這裏是我得到的消息：

「模型生成過程中檢測到一個或多個驗證錯誤：

\ tSystem.Data.Entity.Edm.EdmAssociationConstraint：在財產的數量關係約束中的依賴關係和主體角色必須完全相同。「

下面是我在EntityTypeConfiguration類已經試過和它的顯然是不正確......

public class CourseRecipeChoiceConfiguration : EntityTypeConfiguration<CourseRecipeChoice> 
{ 
    public CourseRecipeChoiceConfiguration() 
    { 
     HasKey(crc => new { crc.Id}); 
     HasRequired(r => r.Recipe).WithMany(crc => crc.CourseRecipeChoices).HasForeignKey(crc => crc.RecipeId); 
     HasRequired(m => m.MenuCourse).WithMany(crc => crc.CourseRecipeChoices).HasForeignKey(crc => crc.MenuCourseId); 
     HasRequired(m => m.MenuCourse).WithMany(crc => crc.CourseRecipeChoices).HasForeignKey(crc => crc.SuggestedMenu_MenuCourseId); 
    } 
} 

什麼是導航屬性的正確語法以及對CourseRecipeChoice流暢API語法正確的語法連接表？

public class SuggestedMenu 
{ 
    public int SuggestedMenuId { get; set; } 

    public virtual ICollection<MenuCourse> MenuCourses { get; set; } 
} 

public class MenuCourse 
{ 
    public int Id { get; set; } 
    public int SuggestedMenuId { get; set; } 

    public SuggestedMenu SuggestedMenu { get; set; } 
    public virtual ICollection<CourseRecipeChoice> CourseRecipeChoices { get; set; } 
} 

public class CourseRecipeChoice 
{ 
    public int SuggestedMenuId { get; set; } 
    public int MenuCourseId { get; set; } 
    public int Id { get; set; } 
    public int RecipeId { get; set; } 

    //How do I represent the navigation properties in this class? 

} 

public class Recipe 
{ 
    public int RecipeId { get; set; } 
    public string Name { get; set; } 
    public string Description { get; set; } 

    public ICollection<CourseRecipeChoice> CourseRecipeChoices { get; set; } 
} 

鍵是如下：

• SuggestedMenu（Id）的
• MenuCourse（ID，SuggestedMenuId）
• CourseRecipeChoice（ID，SuggestedMenuId，MenuCourseId，RecipeId） //這實際上是我感到困惑的地方，因爲根據模型，SuggestedMenuId是SuggestedM中的PK ENU和MenuCourse和CourseRecipeChoice（可能這只是糟糕的設計？）一個PF
• 配方（RecipeId）

Answer 1

...根據手頭的信息（關鍵字，關係並不完全清楚） ，
這裏是最複雜的場景，並應涵蓋你可能有什麼我想......

public class SuggestedMenu 
{ 
    public int SuggestedMenuId { get; set; } 
    public string Description { get; set; } 
    public virtual ICollection<MenuCourse> MenuCourses { get; set; } 
    // public virtual ICollection<CourseRecipeChoice> CourseRecipeChoices { get; set; } 
} 
public class MenuCourse 
{ 
    public int MenuCourseId { get; set; } 
    public int SuggestedMenuId { get; set; } 
    public SuggestedMenu SuggestedMenu { get; set; } 
    public virtual ICollection<CourseRecipeChoice> CourseRecipeChoices { get; set; } 
} 
public class CourseRecipeChoice 
{ 
    public int CourseRecipeChoiceId { get; set; } 
    public int MenuCourseId { get; set; } 
    public int SuggestedMenuId { get; set; } 
    public int RecipeId { get; set; } 
    // no virtuals if required, non-optional 
    public Recipe Recipe { get; set; } 
    public MenuCourse MenuCourse { get; set; } 
    // public SuggestedMenu SuggestedMenu { get; set; } 
} 
public class Recipe 
{ 
    public int RecipeId { get; set; } 
    public string Name { get; set; } 
    public string Description { get; set; } 
    public virtual ICollection<CourseRecipeChoice> CourseRecipeChoices { get; set; } 
} 

...在OnModelCreating（我更喜歡它的所有配置方面所做的工作，但它是相同的）.. 。

modelBuilder.Entity<CourseRecipeChoice>() 
    .HasKey(crc => new { crc.CourseRecipeChoiceId, crc.SuggestedMenuId, crc.MenuCourseId, crc.RecipeId }); 

modelBuilder.Entity<CourseRecipeChoice>() 
    .HasRequired(r => r.Recipe) 
    .WithMany(crc => crc.CourseRecipeChoices) 
    .HasForeignKey(crc => crc.RecipeId) 
    .WillCascadeOnDelete(false); 

modelBuilder.Entity<CourseRecipeChoice>() 
    .HasRequired(m => m.MenuCourse) 
    .WithMany(crc => crc.CourseRecipeChoices) 
    .HasForeignKey(crc => new { crc.MenuCourseId, crc.SuggestedMenuId }) 
    .WillCascadeOnDelete(false); 

modelBuilder.Entity<SuggestedMenu>() 
    .HasKey(crc => crc.SuggestedMenuId); 

modelBuilder.Entity<MenuCourse>() 
    .HasKey(crc => new { crc.MenuCourseId, crc.SuggestedMenuId }); 

modelBuilder.Entity<MenuCourse>() 
    .HasRequired(m => m.SuggestedMenu) 
    .WithMany(crc => crc.MenuCourses) 
    .HasForeignKey(crc => crc.SuggestedMenuId) 
    .WillCascadeOnDelete(false); 

modelBuilder.Entity<Recipe>() 
    .HasKey(crc => crc.RecipeId); 

...並測試例如像...

 using (var db = new YourDbContext()) 
     { 
      SuggestedMenu suggestedmenu = new SuggestedMenu { Description = "suggested menu" }; 
      var menucourse = new MenuCourse { MenuCourseId = 2, SuggestedMenu = suggestedmenu }; 
      var recipe = new Recipe { Name = "My recipe", Description = "recipe desc" }; 
      var crc = new CourseRecipeChoice { CourseRecipeChoiceId = 2, MenuCourse = menucourse, Recipe = recipe, }; 
      db.CourseRecipeChoices.Add(crc); 
      int recordsAffected = db.SaveChanges(); 
      foreach (var crcs in db.CourseRecipeChoices.Include(c => c.MenuCourse).Include(c => c.Recipe)) 
      { 
       Console.WriteLine("{0}, {1}, {2}, {3}", crcs.MenuCourse.MenuCourseId, crcs.MenuCourse.SuggestedMenuId, crcs.Recipe.Name, crcs.Recipe.Description); 
      } 
     }