entity-framework - 联接表中的代码优先Fluent API和导航属性

Question

我有四个实体，我想先通过代码流利的api将其转换为数据库表(我使用的是在databaseanswers.org上找到的模型)，但不确定如何。我遇到的问题是，SuggestedMenuId正在复合键(MenuCourse和CourseRecipeChoice)中的两个不同表之间迁移。

这是我收到的消息:

“在模型生成过程中检测到一个或多个验证错误:

\tSystem.Data.Entity.Edm.EdmAssociationConstraint::关系约束中的从属角色和主体角色的属性数必须相同。”

这是我在EntityTypeConfiguration类中尝试过的方法，这显然是不正确的...

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);
    }
}

导航属性的正确语法和CourseRecipeChoice联接表的流利api语法的正确语法是什么？

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; }
}

键如下:

建议菜单(Id)

菜单类(class)(ID，SuggestedMenuId)

CourseRecipeChoice(Id，SuggestedMenuId，MenuCourseId，RecipeId)//这实际上让我感到困惑，因为根据模型，SuggestedMenuId是SuggestedMenu中的PK，而MenuCourse和CourseRecipeChoice中的PF(这可能是错误的设计吗？)

配方(RecipeId)

Answer 1

...根据手头的信息(键，关系尚不完全清楚)，
这是最复杂的情​​况，应该涵盖您可能的想法...

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; }
}

...以及OnModelCreating(我希望所有配置都在那里完成，尽管是相同的)...

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 );

...并进行测试就像是...

        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);
            }
        }