如何使用 enum 和 json 在数据库中插入数据？

Question

我正在尝试创建一个问题表，其中包含描述性和选择以及是否问题，并且我想将所有问题插入一个表中。 当我想创建选择问题时，我想使用 enum 和 json 将选择插入表中，就像 YesNo 问题一样。我也想选择问题表的正确答案。我怎样才能做到这一点？ 这是我的问题课：

 public class Question
{
    [Key]
    public int Id { get; set; }//1
    public int CourseId { get; set; }
    public string QuestionTitle { get; set; }
    public decimal Grade { get; set; }
    public DateTime TimeDuration { get; set; }
    public DateTime StartTime { get; set; }
    [EnumDataType(typeof(Choice))]
    public string Choice { get; set; }
    public string CorrectChoice { get; set; }
    [EnumDataType(typeof(YesNo))]
    public bool? YesNo { get; set; }
    public string Descriptive { get; set; }

    #region relations
    public virtual IdentityUser IdentityUser { get; set; }
    public Course course { get; set; }
    #endregion
}
public enum Choice
{
    Choice1, Choice2, Choice3, Choice4
}
public enum YesNo
{
    Yes, No
}

当我尝试为问题创建单独的表（描述表、YesNo 表、选择表）时，我的主管说这是不对的，您应该按照上述方式进行操作。

Answer 1

我认为您正在寻找一个额外的表格来存储您的选择，因为您需要每个问题的选择列表，对吧？

public class QuestionChoice
{
    [Key]
    public int Id { get; set; }
    public string Description { get; set; }
    public bool IsTheCorrectAnswer { get; set; }

    #region relations
    // This should point to the question the choice belongs to
    public Question Question { get; set; }
    #endregion
}

然后使用导航属性更新您的 Question 类到选项列表：

public class Question
{
    [Key]
    public int Id { get; set; }
    public int CourseId { get; set; }
    public string QuestionTitle { get; set; }
    public decimal Grade { get; set; }
    public DateTime TimeDuration { get; set; }
    public DateTime StartTime { get; set; }
    [EnumDataType(typeof(YesNo))]
    public bool? YesNo { get; set; }
    public string Descriptive { get; set; }

    #region relations
    public virtual IdentityUser IdentityUser { get; set; }
    public Course course { get; set; }
    
    // New property instead of 'Choice' and 'CorrectChoice'
    public List<QuestionChoice> Choices { get; set; }
    #endregion
}

插入和检索带有选项的问题：

var question = new Question
{
    // Set all properties...

    Descriptive = "What color is a Marigold flower?",
    Choices = new List<QuestionChoice>
    {
        new QuestionChoice
        {
            Description = "It's red!",
            IsTheCorrectAnswer = false
        },
        new QuestionChoice
        {
            Description = "It's yellow!",
            IsTheCorrectAnswer = true
        }
    }
};

// Insert into the database
_dbContext.Questions.Add(question);
_dbContext.SaveChanges();

// Read from the database
var question = _dbContext.Questions.FirstOrDefault(q => q.Id == 1); // Whatever ID it has
var choices = question.Choices;
// ...