Question

我有一家餐厅。餐厅可以提供多种特色菜。特色菜是例如chinees，spahnish，greeks等。

餐厅桌/类：

[Table("Restaurant")]
public class Restaurant
{
    [Key]
    [Column(Order = 0)]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }

    [Required]
    [MaxLength(40)]
    [Column(Order = 2)]
    public string Name { get; set; } 

    [MaxLength(1000)]
    [Column(Order = 6)]
    public string Comments { get; set; }

    public virtual ICollection<Specialties> Specialties { get; set; }
}

这是我的专业表/班级：

 public enum Specialty
    {
        Chinees = 0,
        Spanish = 1,
        Etc.. = 2,
    }

    [Table("Specialties")]
    public class Specialties
    {
        [Key]
        [Column(Order = 0)]
        [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        [Required]
        [Column(Order = 1)]
        public Specialty Specialty { get; set; } 

        //[Required]
        [MaxLength(20)]
        [Column(Order = 2)]
        public string Name { get; set; } 

        public virtual ICollection<Restaurant> Restaurant { get; set; }
    }

专业表预先填充了数据。

这是我的表/类，用于多对多的关系：

[Table("RestaurantSpecialties")]
    public class RestaurantSpecialties
    {
        [Key]
        public int RestaurantId { get; set; }

        [Key]
        public int SpecialtyId { get; set; }

        [ForeignKey("RestaurantId")]
        public virtual Restaurant Restaurant{ get; set; }

        [ForeignKey("SpecialtyId")]
        public virtual Specialties Specialty { get; set; }
    }

使用Fluent Api我试图像这样定义模型：

// Primary keys
modelBuilder.Entity<Restaurant>().HasKey(q => q.Id);
modelBuilder.Entity<Specialties>().HasKey(q => q.Id);

// Relationship
modelBuilder.Entity<Restaurant>()
    .HasMany(q => q.Specialties)
    .WithMany(q => q.Restaurant)
    .Map(q =>
    {
        q.ToTable("RestaurantSpecialty");
        q.MapLeftKey("RestaurantId");
        q.MapRightKey("SpecialtyId");
    });

在我的种子功能中，我正在播种这样的数据：

context.Specialties.AddOrUpdate(
    p => p.Specialty,
    new Specialties { Specialty = Specialty.Chinees, Name = "Chinees" },
    new Specialties { Specialty = Specialty.Spanish, Name = "Spanish" },
    );

ICollection<Specialties> lstSpecialties = new List<Specialties>();
lstSpecialties.Add(context.Specialties.FirstOrDefault(x => x.Name == "Chinees"));

context.Restaurants.AddOrUpdate(
  p => p.Name,
  new Restaurant{ Name = "Ctr test1", Specialties = lstSpecialties, Comments = "sfasd" },
  new Restaurant{ Name = "Ctr test2", Specialties = lstSpecialties, Comments = "asd" },
  );

但我的餐厅RestaurantSpecialties不含任何东西。我期待看到两张桌子的Id。

我做错了什么？

[编辑]

enum已经从'Specialty'重命名为'RestaurantSpecialty'，就像Gert建议做的那样（只是重命名部分，而不是实际名称）。

复数类'Specialties'也被重命名为'Specialty'。也因为格特建议。

联接表也已从模型中删除。我原始帖子中的Fluent Api部分已相应更新。

餐饮已更名为餐厅，我忘了在开始时这样做。因此，为了避免混淆，我在原始代码中也做了这个。

context.Specialties.AddOrUpdate(
   new Specialty { CateringSpecialty = RestaurantSpecialty.Chinese, Name = "Chinese" },
   new Specialty { CateringSpecialty = CateringSpecialty.Greeks, Name = "Greeks" },
);


var aSpecialty = context.Specialties.FirstOrDefault(x => x.Name == "Chinese");
var restaurant1 = context.Restaurants.Include(c => c.Specialties).FirstOrDefault(x => x.Name == "Ctr test1");

 if (restaurant1 == null)
 {
    restaurant1 = new Restaurant
    {
         Name = "Ctr test4",
         Specialties = new List<Specialty> { aSpecialty },
         Comments = "testtttttttt"
    };
    context.Restaurants.Add(restaurant1);
 }
 else
 {
   if (!restaurant1.Specialties.Any(s => s.Id == aSpecialty.Id))
        restaurant1.Specialties.Add(aSpecialty);

       restaurant1.Name = "Ctr test4";
       restaurant1.Comments = "testtttt";
 }

Answer 1

尝试手动添加/更新。我怀疑AddOrUpdate方法不支持更新相关实体的完整对象图。如果父实体尚不存在，它可能支持将相关实体与其父实体一起添加。但是，如果“Chinees”专业已经存在于没有相关实体的数据库中，则关系可能无法更新。

“手动更新”如下所示：

context.Specialties.AddOrUpdate( p => p.Specialty, new Specialties { Specialty = Specialty.Chinees, Name = "Chinees" }, new Specialties { Specialty = Specialty.Spanish, Name = "Spanish" }, ); var chineesSpecialty = context.Specialties .FirstOrDefault(x => x.Name == "Chinees"); var catering1 = context.Caterings.Include(c => c.Specialties) .FirstOrDefault(x => x.Name == "Ctr test1"); if (catering1 == null) { catering1 = new Catering { Name = "Ctr test1", Specialties = new List<Specialties> { chineesSpecialty }, Comments = "sfasd" }; context.Caterings.Add(catering1); } else { if (!catering1.Specialties.Any(s => s.Id == chineesSpecialty.Id)) catering1.Specialties.Add(chineesSpecialty); catering1.Comments = "sfasd"; } // and the same for "Ctr test2"

这也提到in this answer，但它是在Code-First Migrations的早期预览版本中，所以我不确定这个限制是否仍然存在。但它可以解释为什么你不在关系表中获得条目。

您的映射本身对我来说是正确的。（但正如Gert Arnold在评论中已经建议的那样，我真的会删除看起来多余的RestaurantSpecialties实体并且只会使你的模型复杂化。）

Code First关系一对多/多对多

1 个答案: