连接表中的Code First Fluent API和导航属性

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问题描述

我有四个实体，我想通过代码第一流利api（我使用在databaseanswers.org找到的模型）翻译成数据库表，但我不确定如何。我遇到的问题是SuggestedMenuId正在复合键（MenuCourse和CourseRecipeChoice）中的两个不同的表中进行迁移。

这是我得到的消息： / p>

在模型生成期间检测到一个或多个验证错误：

\tSystem.Data.Entity.Edm .EdmAssociationConstraint：：关系约束中从属和主体角色中的属性数必须相同。

这是我在EntityTypeConfiguration类中尝试过的，它是显然不正确...

  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）; 
} 
}

导航属性和用于CourseRecipeChoice连接表流畅api语法的正确语法？

  public class SuggestedMenu 
 {
 public int SuggestedMenuId {get;组; } 
 
 public virtual ICollection< MenuCourse> MenuCourses {get;组; } 
} 
 
 public class MenuCourse 
 {
 public int Id {get;组; } 
 public int SuggestedMenuId {get;组; } 
 
 public SuggestedMenu SuggestedMenu {get;组; } 
 public virtual ICollection< CourseRecipeChoice> CourseRecipeChoices {get;组; } 
} 
 
 public class CourseRecipeChoice 
 {
 public int SuggestedMenuId {get;组; } 
 public int MenuCourseId {get;组; } 
 public int Id {get;组; } 
 public int RecipeId {get;组; } 
 
 //如何表示此类中的导航属性？ 
 
} 
 
 public class配方
 {
 public int RecipeId {get;组; } 
 public string Name {get;组; } 
 public string描述{get;组; } 
 
 public ICollection< CourseRecipeChoice> CourseRecipeChoices {get;组; 
}

密钥如下：

SuggestedMenu（Id）

MenuCourse（Id，SuggestedMenuId） li>
CourseRecipeChoice（Id，SuggestedMenuId，MenuCourseId，RecipeId） //这实际上是在我被困惑的地方，因为根据模型，SuggestedMenuId是SuggestedMenu中的PK和PF在MenuCourse和CourseRecipeChoice（这可能只是坏的设计？）

配方（RecipeId）

解决方案

...根据手头的信息（键，关系不完全清楚），

这里是最复杂的场景并且应该涵盖你可能有的想法...

  public class SuggestedMenu 
 {
 public int SuggestedMenuId {get;组; } 
 public string描述{get;组; } 
 public virtual ICollection< MenuCourse> MenuCourses {get;组; } 
 // public virtual ICollection< CourseRecipeChoice> CourseRecipeChoices {get;组; } 
} 
 public class MenuCourse 
 {
 public int MenuCourseId {get;组; } 
 public int SuggestedMenuId {get;组; } 
 public SuggestedMenu SuggestedMenu {get;组; } 
 public virtual ICollection< CourseRecipeChoice> CourseRecipeChoices {get;组; 
} 
 public class CourseRecipeChoice 
 {
 public int CourseRecipeChoiceId {get;组; } 
 public int MenuCourseId {get;组; } 
 public int SuggestedMenuId {get;组; } 
 public int RecipeId {get;组; } 
 //如果需要，没有虚拟的，非可选的
 public Recipe Recipe {get;组; } 
 public MenuCourse MenuCourse {get;组; } 
 // public SuggestedMenu SuggestedMenu {get;组; 
} 
 public class Recipe 
 {
 public int RecipeId {get;组; } 
 public string Name {get;组; } 
 public string描述{get;组; } 
 public virtual ICollection< CourseRecipeChoice> CourseRecipeChoices {get;组; 
}

...和 OnModelCreating （我更喜欢所有配置在那里，虽然是一样的）...

  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）;

...并测试例如像$ ...

$ b $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ = new SuggestedMenu {Description =建议菜单};
var menucourse = new MenuCourse {MenuCourseId = 2，SuggestedMenu = suggestmenu};
var recipe = new Recipe {Name =我的食谱，描述=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）;
}
}

I have four entities that I would like to translate into database tables via code first fluent api (I'm using a model found at databaseanswers.org), but I'm not certain as to how. The problem I'm having is that SuggestedMenuId is being migrated across two different tables in a Composite key (MenuCourse and CourseRecipeChoice).

Here's the message I'm getting:

"One or more validation errors were detected during model generation:

\tSystem.Data.Entity.Edm.EdmAssociationConstraint: : The number of properties in the Dependent and Principal Roles in a relationship constraint must be identical."

Here's what I've tried in my EntityTypeConfiguration class and it's obviously incorrect...

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);
    }
}

What is the correct syntax for the navigation properties and the correct syntax for fluent api syntax for the CourseRecipeChoice join table?

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; }
}

The keys are as follows:

SuggestedMenu(Id)
MenuCourse(Id, SuggestedMenuId)
CourseRecipeChoice(Id, SuggestedMenuId, MenuCourseId, RecipeId) //this is actually where I get confused because according to the model, SuggestedMenuId is a PK in SuggestedMenu and a PF in MenuCourse and CourseRecipeChoice (could this just be bad design?)
Recipe(RecipeId)

解决方案

...based on the info at hand (keys, relationships are not entirely clear),
here is the most complex scenario and should cover what you might have I think...

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; }
}

...and in OnModelCreating (I prefer it all config done there, though it's the same)...

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 );

...and to test e.g. something like...

        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);
            }
        }

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