实体框架 Fluent API

Question

我的实体如下...

public class Project{

       public int Id { get; set; }
       public string Name { get; set; }
       public string Description { get; set; }

       public virtual ICollection<Survey> Surveys { get; set; }
}

public class Survey{

       public int Id { get; set; }
       public int ProjectId { get; set; }
       public string Name { get; set; }

       public virtual Project Project { get; set; }

}

public class Category{
        public int Id { get; set; }
        public string Name { get; set; }

        public virtual ICollection<Survey> Surveys { get; set; }
    }

public class SurveyCategory{

        public int Id { get; set; }
        public int SurveyId{ get; set; }
        public int CategoryId { get; set; }
        public string Name { get; set; }

        public virtual Survey Survey { get; set; }
        public virtual Category Category { get; set; }

}

一个项目将有调查列表，一个调查将只有一个类别，一个类别可以有多个调查，调查类别是我存储调查 + 类别链接的表。

谁能告诉我什么是合适的 Fluent API 代码才能正确映射....到目前为止我有这个....

 protected override void OnModelCreating(DbModelBuilder modelBuilder){          
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
        modelBuilder.Entity<Project>().HasMany(project => project.Surveys);}

Answer 1

嗨，我希望我明白你在寻找什么。

首先你应该对你的模型做一些改变

public class Project
{
  public int Id { get; set; }
  public string Name { get; set; }
  public string Description { get; set; }

  public virtual ICollection<Survey> Surveys { get; set; }
} 
public class Survey
{
  public int Id { get; set; }
  public int ProjectId { get; set; }
  public int CategoryId { get; set; }
  public string Name { get; set; }

  public virtual Project Project { get; set; }
  public virtual Category Category { get; set; }
  public virtual ICollection<SurveyCategory> SurveyCategory { get; set; }
}
public class Category
{
  public int Id { get; set; }
  public string Name { get; set; }

  public virtual ICollection<Survey> Surveys { get; set; }
  public virtual ICollection<SurveyCategory> SurveyCategory { get; set; }
}
public class SurveyCategory
{
  public int Id { get; set; }
  public string Name { get; set; }
  public int SurveyId { get; set; }
  public virtual Survey Survey { get; set; }
  public int CategoryId { get; set; }
  public virtual Category Category { get; set; }
}

然后在创建模型时你应该这样做

protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Project>()
                    .HasMany(p => p.Surveys)
                    .WithRequired(u => u.Project);
        modelBuilder.Entity<Category>()
                    .HasMany(p => p.Surveys)
                    .WithRequired(u => u.Category);
        modelBuilder.Entity<Category>()
                    .HasMany(p => p.SurveyCategory)
                    .WithRequired(u => u.Category)
                    .HasForeignKey(k => k.CategoryId)
                    .WillCascadeOnDelete(false);
        modelBuilder.Entity<Survey>()
                   .HasMany(p => p.SurveyCategory)
                   .WithRequired(u => u.Survey)
                   .HasForeignKey(k => k.SurveyId)
                   .WillCascadeOnDelete(false);
    }

希望对你有帮助