製作多個表並添加1：1..0的關係

Question

我幾乎是一個菜鳥，所以我會很感激我的代碼的一些評論，因爲我在這裏自己學習。如果我正確地做了他們，我想對我的關係映射提供一些反饋，因爲我現在有疑問。 （任何提示如何更正確地檢查我自己也是受歡迎的！）

我有一個數據庫與用戶，但我的一些用戶是供應商。當然這是一個選項。起初我只是認爲我會分配一個bool來存儲它在我的數據庫中，但現在我正在擴展它，以便我的供應商可以獲得評論。

這就是我如何去做的。 我的供應商模式：

public partial class Suppliers 
    { 
    public Suppliers() 
    { 
     Id = GuidComb.GenerateComb(); 
    } 
    public Guid Id { get; set; } 
    public virtual IList<SupplierReview> SupplierReviews { get; set; } 
    public virtual MembershipUser user { get; set; } 
    } 

然後我的評價模型：

public partial class SupplierReview : Entity 
{ 
    //int: 0-255; score can only be 10 so this is a good fit. 
    private int answerScore; 
    private int timeScore; 
    private int priceScore; 
    private int qualityScore; 

    public SupplierReview() 
    { 
     Id = GuidComb.GenerateComb(); 
     qualityScore = 5; 
     timeScore = 5; 
     priceScore = 5; 
     answerScore = 5; 
    } 
    public Guid Id { get; set; } 

    //these sets make sure that the score can only be one to 10 
    public int QualityScore 
    { 
     get 
     { 
      return qualityScore; 
     } 
     set 
     { 
      qualityScore = value % 10; 
     } 
    } 
    public int TimeScore 
    { 
     get 
     { 
      return timeScore; 
     } 
     set 
     { 
      timeScore = value % 10; 
     } 
    } 
    public int PriceScore 
    { 
     get 
     { 
      return priceScore; 
     } 
     set 
     { 
      priceScore = value % 10; 
     } 
    } 
    public int AnswerScore 
    { 
     get 
     { 
      return answerScore; 
     } 
     set 
     { 
      answerScore = value % 10; 
     } 
    } 
    public string Comment { get; set; } 

    public virtual MembershipUser User { get; set; } 
    public virtual Suppliers Supplier { get; set; } 
} 

，然後向會員模式，我說：

public virtual IList<SupplierReview> SupplierReviews { get; set; } 
    public virtual Suppliers IsSupplier { get; set; } 

的然後在我的映射：

public class SuppliersMapping : EntityTypeConfiguration<Suppliers> 
{ 
    public SuppliersMapping() 
    { 
     HasKey(x => x.Id); 
     Property(x => x.Id).IsRequired(); 

     HasMany(x => x.SupplierReviews).WithRequired(x => x.Supplier) 
      .Map(x => x.MapKey("Suppliers_Id")) 
      .WillCascadeOnDelete(false); 
    } 
} 

public class SupplierReviewMapping : EntityTypeConfiguration<SupplierReview> 
{ 
    public SupplierReviewMapping() 
    { 
     HasKey(x => x.Id); 
     Property(x => x.Id).IsRequired(); 

     Property(x => x.Comment).IsOptional().HasMaxLength(1000); 
     Property(x => x.QualityScore).IsOptional(); 
     Property(x => x.PriceScore).IsOptional(); 
     Property(x => x.TimeScore).IsOptional(); 
     Property(x => x.AnswerScore).IsOptional(); 

     HasRequired(x => x.User).WithMany(x => x.SupplierReviews) 
      .Map(x => x.MapKey("MembershipUser_Id")) 
      .WillCascadeOnDelete(false); 

     HasRequired(t => t.Supplier).WithMany(t =>t.SupplierReviews) 
      .Map(m => m.MapKey("Suppliers_Id")) 
      .WillCascadeOnDelete(false); 

    } 
} 

和i n我的會員資格映射：

 HasOptional(x => x.IsSupplier) 
      .WithOptionalDependent() 
      .Map(p => p.MapKey("Suppliers_Id")); 
     HasMany(x=>x.SupplierReviews).WithRequired(x => x.User) 
      .Map(x=> x.MapKey("MembershipUser_Id")) 
      .WillCascadeOnDelete(false); 

感謝您閱讀這篇文章。所以我的疑惑是一般的映射，如果我正確使用WillCascadeOnDelete？

Answer 1

一些映射是基於觀點的，這意味着有些時候沒有「正確的答案」。如果我理解正確的情況下，我建議你做這些改變：

1. 如果User可以是Supplier，但並不是所有的供應商都User：

   public class MembershipUser 
   { 
       public Guid MembershipUserId { get; set; } 
   
       public IsSupplier { get; set; } //I like to have a discriminator field 
   
       //if it is a supplier, there is a relationship with the supplier table 
       //it it is not, the property will be null 
       public Supplier Supplier { get; set; } 
   } 
   
   public class Supplier 
   { 
       //pk 
       public Guid SupplierId { get; set; }    
   
       //navigation property 
       public MembershipUser User { get; set; } 
   
       //... other properties 
   } 
   

   映射：

   modelBuilder.Entity<MembershipUser>() 
       .HasKey(i => i.MembershipUserId); 
   
   modelBuilder.Entity<MembershipUser>() 
       .HasOptional(i => i.Supplier) 
       .WithOptionalPrincipal(i => i.User) 
       .Map(i => i.MapKey("MemberhsipUserId")) 
       .WillCascadeOnDelete(false); 
   
   modelBuilder.Entity<Supplier>() 
       .HasKey(i => i.SupplierId); 
   

2. 如果所有供應商都是User：

   public class Supplier 
   { 
       //The SupplierPK must be the MembershipUser Fk 
       public Guid MembershipUserId { get; set; }    
   
       //navigation property, in case of the supplier is an user 
       public MembershipUser User { get; set; } 
   
       //... other properties 
   } 
   

   映射：

   modelBuilder.Entity<MembershipUser>() 
       .HasOptional(i => i.Supplier) 
       .WithRequired(i => i.User) 
       .WillCascadeOnDelete(false); 
   

關於SupplierReview，它不需要MembershipUser財產，只是Supplier屬性：

modelBuilder.Entity<SupplierReview>() 
    .HasRequired(i => i.Supplier) 
    .WithMany(i => i.SupplierReviews) 
    .HasForeignKey(i => i.SupplierId) 
    .WillCascadeOnDelete(false); 

希望它能幫助！