關係和外鍵錯誤與實體框架4.1

Question

我有麻煩了如下描述：

One or more validation errors were detected during model generation: 

System.Data.Edm.EdmAssociationType: : Multiplicity conflicts with the referential constraint in Role 'CorpQuestionA_CorpQAnswer_Source' in relationship 'CorpQuestionA_CorpQAnswer'. Because all of the properties in the Dependent Role are non-nullable, multiplicity of the Principal Role must be '1'. 

我的屏幕截圖PIC數據庫：

和實體限定：

public class CorpQuestionA 
{ 
    [Key] 
    public Guid cqua_QuestionId { get; set; } 
    public Guid cqua_CorpId { get; set; } 
    [MaxLength] 
    public string cqua_Question { get; set; } 
    public DateTime cqua_Date { get; set; } 
    public Boolean cqua_IsAnswer { get; set; } 

    [ForeignKey("cqua_CorpId")] 
    public virtual CorpRegInfo510112 CorpRegInfo510112 { get; set; } 
    public virtual CorpQAnswer CorpQAnswer { get; set; } 
} 


public class CorpQAnswer 
{ 
    [Key] 
    public Guid cqan_QuestionId { get; set; } 
    public string cqan_Answer { get; set; } 

    [ForeignKey("cqan_QuestionId")] 
    public virtual CorpQuestionA CorpQuestionA { get; set; } 
} 

然後是ProjectDataEntities文件：

public class ProjectDataEntities : DbContext 
{ 
    public DbSet<CorpQuestionA> Tbl_CorpQuestionAs { get; set; } 
    public DbSet<CorpQAnswer> Tbl_CorpQAnswers { get; set; } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     base.OnModelCreating(modelBuilder); 
     modelBuilder.Conventions.Remove<IncludeMetadataConvention>(); 

     modelBuilder.Entity<CorpQuestionA>().ToTable("tbl_CorpQuestionA"); 
     modelBuilder.Entity<CorpQAnswer>().ToTable("tbl_CorpQAnswer"); 

     //Todo: Add custom mapping rules here... 
     modelBuilder.Entity<CorpQuestionA>().HasOptional(p => p.CorpQAnswer).WithOptionalPrincipal(x => x.CorpQuestionA);//.Map(p => p.MapKey("cqua_QuestionId")); 
    } 
} 

當我做更新操作，它拋出一個異常，因爲描述之前

public bool AnswerCorpQuestion(AnswerCorpQuestionModel acqModel) 
    { 
     var prjPO = new ProjectDataEntities(); 

     //update table CorpQuestionA 
     CorpQuestionA cqaModel0 = prjPO.Tbl_CorpQuestionAs.Find(acqModel.cqua_QuestionId); 
     cqaModel0.cqua_IsAnswer = acqModel.cqua_IsAnswer; 

     //insert table CorpQAnswer 
     CorpQAnswer cqaModel1 = new CorpQAnswer 
     { 
      cqan_QuestionId = acqModel.cqua_QuestionId, 
      cqan_Answer=acqModel.cqan_Answer 
     }; 
     prjPO.Tbl_CorpQAnswers.Add(cqaModel1); 

     try 
     { 
      prjPO.SaveChanges(); 
      return true; 
     } 
     catch(DbEntityValidationException dbEx) 
     { 
      throw dbEx; 
     } 
    } 

等待幫助，THX

Answer 1

更改共享主鍵如下。

protected override void OnModelCreating(DbModelBuilder modelBuilder) 
{ 
    base.OnModelCreating(modelBuilder); 
    modelBuilder.Conventions.Remove<IncludeMetadataConvention>(); 

    modelBuilder.Entity<CorpQuestionA>().ToTable("tbl_CorpQuestionA"); 
    modelBuilder.Entity<CorpQAnswer>().ToTable("tbl_CorpQAnswer"); 

    modelBuilder.Entity<CorpQuestionA>().HasOptional(p => p.CorpQAnswer) 
     .WithRequired(x => x.CorpQuestionA); 
}