实体框架的多样性

本文关键字：多样性 框架 实体 | 更新日期: 2023-09-27 18:16:52

我是新的实体框架，我遇到了一些问题，而试图实现我的ERD代码第一。情况如下:

ERD

产品有一组问题(QuestionGroup)。一个QuestionGroup有多个问题，可以属于多个Questionaires。问卷基本上有一个问题组和一个问题单。问题顺序应该保留问题在该问卷中的位置。之所以需要Questionaire表，是因为一个QuestionGroup可以有多个问题单，而一个问题单可以属于多个问题组。

因为我尽量保持这篇文章的简洁，所以我不会把我所有的课程都贴出来，除非你要求看。我所做的实体类看起来像这样:

public class Question
    {
        [Key]
        public int Id { get; set; }
        [MaxLength(2000)]
        [Required]
        public string Text { get; set; }
        public Answer Answer { get; set; }
        public QuestionType Type { get; set; }
        public ICollection<QuestionAnswerOption> Options { get; set; }
        public ICollection<QuestionOrder> Orders { get; set; }
        [ForeignKey("FollowupQuestion")]
        public int QuestionId { get; set; }
        public virtual Question FollowupQuestion { get; set; }
        [ForeignKey("Questiongroup")]
        public int QuestionGroupId { get; set; }
        public virtual QuestionGroup Questiongroup { get; set; }
    }
public class QuestionOrder
    {
        [Key]
        public int Id { get; set; }
        public int Position { get; set; }
        [ForeignKey("Question")]
        [Required]
        public int QuestionId { get; set; }
        public virtual Question Question { get; set; }
        [ForeignKey("Questionaire")]
        [Required]
        public int QuestionaireId { get; set; }
        public virtual Questionaire Questionaire { get; set; }
    }
  public class Product
    {
        [Key]
        public int Id { get; set; }
        [MaxLength(150)]
        [Required]
        [Index(IsUnique = true)]
        public string Name { get; set; }
        [MaxLength(500)]
        public string Summary { get; set; }
        [MaxLength(500)]
        public string Examples { get; set; }
        public virtual QuestionGroup QuestionGroup { get; set; }
    }
public class QuestionGroup
    {
        [Key]
        public int Id { get; set; }
        public ICollection<Question> Questions { get; set; }
        [ForeignKey("Product")]
        public int ProductId { get; set; }
        public virtual Product Product { get; set; }
    }
 public class Questionaire
    {
        [Key]
        public int Id { get; set; }
        public QuestionGroup Group { get; set; }
        public QuestionOrder Order { get; set; }
    }

我得到的错误看起来像这样:

关系'QuestionGroup_Product'中的角色'QuestionGroup_Product_Source::多重性无效。因为从属角色属性不是关键属性，所以从属角色的多重性的上界必须是'*'。

关系' questionorder_questionnaire '中的角色'QuestionOrder_Questionaire_Source::多重性无效。因为从属角色属性不是关键属性，所以从属角色的多重性的上界必须是'*'。

关系'QuestionType_Question'中的角色'QuestionType_Question_Source::多重性无效。因为从属角色属性不是关键属性，所以从属角色的多重性的上界必须是'*'。

我们在这里得到的问题是:这里有人知道一种方法来修复我的表之间的关系吗?也许我的ERD也需要一些改进，但我认为问题是我在代码优先的实现中缺少了一些东西。

实体框架的多样性

你觉得这个设计怎么样;)

public class Customer
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int CustomerId { get; set; }
    public string CompanyName { get; set; }
    public virtual ICollection<ContactInfo> ContactInfoes { get; set; }
    public virtual ICollection<ProductQuestionaireReport> Reports { get; set; }
}
public class ContactInfo
{
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    [Key]
    public int ContactInfoId { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public int Telephone { get; set; }
    [ForeignKey("Customer")]
    public int CustomerId { get; set; }
    public virtual Customer Customer { get; set; }
}
public class ProductQuestionaireReport
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int ProductQuestionaireReportId { get; set; }
    [ForeignKey("Product")]
    public int ProductId { get; set; }
    public virtual Product Product { get; set; }
    public virtual QuestionaireResult Result { get; set; }
    [ForeignKey("Customer")]
    public int CustomerId { get; set; }
    public virtual Customer Customer { get; set; }
    public bool Haste { get; set; }
    public string Status { get; set; }
    public string Comment { get; set; }
}
public class QuestionaireResult
{
    [Key, ForeignKey("ProductQuestionaireReport")]
    public int ProductQuestionaireReportId { get; set; }
    [ForeignKey("Questionaire")]
    public int QuestionaireId { get; set; }
    public virtual Questionaire Questionaire { get; set; }
    public DateTime SurveyCreated { get; set; }
    public Double Costs { get; set; }
    public Double FunctionPoints { get; set; }
    public virtual ProductQuestionaireReport ProductQuestionaireReport { get; set; }
    public virtual ICollection<QuestionaireAnswer> Answers { get; set; }
}
public class Product
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int ProductId { get; set; }
    public string Name { get; set; }
    public string Summary { get; set; }
    public string Examples { get; set; }
    public virtual ICollection<Questionaire> Questionaires { get; set; }
    public virtual ICollection<ProductQuestionaireReport> Reports { get; set; }
}
public class QuestionaireAnswer
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int QuestionaireAnswerId { get; set; }
    [ForeignKey("QuestionaireResult")]
    public int QuestionaireResultId { get; set; }
    public virtual QuestionaireResult QuestionaireResult { get; set; }
    [ForeignKey("QuestionaireQuestion")]
    public int QuestionaireId { get; set; }
    public virtual QuestionaireQuestion QuestionaireQuestion { get; set; }
    [ForeignKey("Answer")]
    public int AnswerId { get; set; }
    public virtual QuestionOption Answer { get; set; }
    public string Text { get; set; }
    public virtual ICollection<string> Files { get; set; }
}
public class Questionaire
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int QuestionaireId { get; set; }
    [ForeignKey("Product")]
    public int ProductId { get; set; }
    public virtual Product Product { get; set; }
    public virtual ICollection<QuestionaireQuestion> QuestionaireQuestions { get; set; }
    public virtual ICollection<QuestionaireResult> Results { get; set; }
}
public class Question
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int QuestionId { get; set; }
    [ForeignKey("ParentQuestion")]
    public int ParentQuestionId { get; set; }
    public virtual Question ParentQuestion { get; set; }
    public virtual QuestionType QuestionType { get; set; }
    public virtual ICollection<QuestionOption> Options { get; set; }
}
public class QuestionType
{
    [Key, ForeignKey("Question")]
    public int QuestionId { get; set; }
    public string Text { get; set; }
    public bool IsOpenQuestion { get; set; }
    public virtual Question Question { get; set; }
}
public class QuestionOption
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int QuestionAnswerOptionId { get; set; }
    [ForeignKey("Question")]
    public int QuestionId { get; set; }
    public string Text { get; set; }
    public virtual Question Question { get; set; }
}
public class QuestionaireQuestion
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int QuestionaireQuestionId { get; set; }
    [ForeignKey("Questionaire")]
    public int QuestionaireId { get; set; }
    public virtual Questionaire Questionaire { get; set; }
    [ForeignKey("Question")]
    public int QuestionId { get; set; }
    public int DisplayOrder { get; set; }
    public virtual Question Question { get; set; }
}

还必须将此添加到OnModelCreating 

modelBuilder.Entity<Customer>().HasMany(c => c.ContactInfoes)
    .WithRequired(i => i.Customer).HasForeignKey(i => i.CustomerId).WillCascadeOnDelete(false);
modelBuilder.Entity<Question>().HasMany(q => q.Options)
    .WithRequired(o => o.Question).HasForeignKey(o => o.QuestionId).WillCascadeOnDelete(false);
modelBuilder.Entity<QuestionaireResult>().HasMany(r => r.Answers)
    .WithRequired(a => a.QuestionaireResult).HasForeignKey(o => o.QuestionaireResultId).WillCascadeOnDelete(false);

检查并反馈给我…

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