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EF框架一对多多对多关系总结

原文连接 https://blog.csdn.net/hhhhhhenrik/article/details/89216909

总结几种项目中遇到的一对多多对多关系

1 基本的多对多关系

  public class npc
  {
      public string Name;
      public ICollection<Content> Contents;
  }
public class Content

{

public string Name;
  <span class="token keyword">public</span> ICollection<span class="token generics function"><span class="token punctuation">&lt;</span>npc<span class="token punctuation">&gt;</span></span> npcs<span class="token punctuation">;</span>

}
//fluent api

HasMany(m => m.Contents).WithMany(w => w.npcs).Map(m =>

{

m.ToTable("C_NPC_Content_Relation");

m.MapLeftKey("npcId");

m.MapRightKey("ContentId");

});
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2 同一个表建立两个多对多关系

  
    public class npc
    {
        public string Name;
        public ICollection<Content> Contents1;
        public ICollection<Content> Contents2;
    }
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Content</span>
<span class="token punctuation">{</span>
    <span class="token keyword">public</span> string Name<span class="token punctuation">;</span>

    <span class="token keyword">public</span> ICollection<span class="token generics function"><span class="token punctuation">&lt;</span>npc<span class="token punctuation">&gt;</span></span> npcs<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
 <span class="token comment">//fluent api</span>
<span class="token function">HasMany</span><span class="token punctuation">(</span>m <span class="token operator">=</span><span class="token operator">&gt;</span> m<span class="token punctuation">.</span>Contents1<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">WithMany</span><span class="token punctuation">(</span>w <span class="token operator">=</span><span class="token operator">&gt;</span> w<span class="token punctuation">.</span>npcs<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">Map</span><span class="token punctuation">(</span>m <span class="token operator">=</span><span class="token operator">&gt;</span>
<span class="token punctuation">{</span>
    m<span class="token punctuation">.</span><span class="token function">ToTable</span><span class="token punctuation">(</span><span class="token string">"C_NPC_Content1_Relation"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    m<span class="token punctuation">.</span><span class="token function">MapLeftKey</span><span class="token punctuation">(</span><span class="token string">"npcId"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    m<span class="token punctuation">.</span><span class="token function">MapRightKey</span><span class="token punctuation">(</span><span class="token string">"ContentId"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">HasMany</span><span class="token punctuation">(</span>m <span class="token operator">=</span><span class="token operator">&gt;</span> m<span class="token punctuation">.</span>Contents2<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">WithMany</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">Map</span><span class="token punctuation">(</span>m <span class="token operator">=</span><span class="token operator">&gt;</span>
<span class="token punctuation">{</span>
    m<span class="token punctuation">.</span><span class="token function">ToTable</span><span class="token punctuation">(</span><span class="token string">"C_NPC_Content2_Relation"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    m<span class="token punctuation">.</span><span class="token function">MapLeftKey</span><span class="token punctuation">(</span><span class="token string">"npcId"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    m<span class="token punctuation">.</span><span class="token function">MapRightKey</span><span class="token punctuation">(</span><span class="token string">"ContentId"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

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3 普通的一对多

   public class npc
   {
       public string Name;
       public int ContentId;//外键
   }
public class Content

{

public string Name;

public ICollection<npc> npcs;

}
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4 同一个表建立两份一对多关系

   public class npc
   {
        public string Name;
        public int ContentId_1;//外键1
        public int ContentId_2;//外键2
    }
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Content</span>
<span class="token punctuation">{</span>
    <span class="token keyword">public</span> string Name<span class="token punctuation">;</span>
    <span class="token keyword">public</span> ICollection<span class="token generics function"><span class="token punctuation">&lt;</span>npc<span class="token punctuation">&gt;</span></span> npcs_1<span class="token punctuation">;</span>
    <span class="token keyword">public</span> ICollection<span class="token generics function"><span class="token punctuation">&lt;</span>npc<span class="token punctuation">&gt;</span></span> npcs_2<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token comment">//fluent api(npc)</span>
 <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">HasRequired</span><span class="token punctuation">(</span>t <span class="token operator">=</span><span class="token operator">&gt;</span> t<span class="token punctuation">.</span>Content<span class="token punctuation">)</span>
   <span class="token punctuation">.</span><span class="token function">WithMany</span><span class="token punctuation">(</span>t <span class="token operator">=</span><span class="token operator">&gt;</span> t<span class="token punctuation">.</span>npcs_1<span class="token punctuation">)</span>
   <span class="token punctuation">.</span><span class="token function">HasForeignKey</span><span class="token punctuation">(</span>t <span class="token operator">=</span><span class="token operator">&gt;</span> t<span class="token punctuation">.</span>ContentId_1<span class="token punctuation">)</span>
   <span class="token punctuation">.</span><span class="token function">WillCascadeOnDelete</span><span class="token punctuation">(</span><span class="token boolean">false</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">HasOptional</span><span class="token punctuation">(</span>t <span class="token operator">=</span><span class="token operator">&gt;</span> t<span class="token punctuation">.</span>Content<span class="token punctuation">)</span>
    <span class="token punctuation">.</span><span class="token function">WithMany</span><span class="token punctuation">(</span>t <span class="token operator">=</span><span class="token operator">&gt;</span> t<span class="token punctuation">.</span>npcs_2<span class="token punctuation">)</span>
    <span class="token punctuation">.</span><span class="token function">HasForeignKey</span><span class="token punctuation">(</span>t <span class="token operator">=</span><span class="token operator">&gt;</span> t<span class="token punctuation">.</span>ContentId_2<span class="token punctuation">)</span>
    <span class="token punctuation">.</span><span class="token function">WillCascadeOnDelete</span><span class="token punctuation">(</span><span class="token boolean">false</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

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原文地址：https://www.cnblogs.com/sunny3158/p/11800948.html

EF框架一对多 多对多关系总结

EF框架一对多多对多关系总结