C# 类是否应该为来自字典表的SQL联接的值提供字符串字段

我在下面有一个类代码，我用它来保存到数据库并从数据库中读取。一切正常，但当最终打印一些从字典表中获取的对象信息时，我真的不知道该放在哪里。活动记录

类别代码：

class Object
{
   public int id;
   public int size;
   public int color;
   public int author;

   public Object(int id, int size, int color, int author)
   {
      this.id = id;
      this.size = size;
      this.color = color;
      this.author = author;
   }

   // add, update, delete methods
}

因此，对于上述类，SQL：

从对象中选择id、大小、颜色、作者

我是否应该将字符串字段添加到此类中，使其如下所示：

class Object
{
   public int id;
   public int size;
   public int color;
   public int author;

   // String fields for dictionary
   public string sizeString;
   public string colorString;
   public string authorString;
   //

   // Nr 1
   public Object(int id, int size, int color, int author)
   {
      this.id = id;
      this.size = size;
      this.color = color;
      this.author = author;
   }

   // Nr 2
   public Object(int id, string size, string color, string author)
   {
      this.id = id;
      this.size = sizeString;
      this.color = colorString;
      this.author = authorString;
   }

   // add, update, delete methods
}

SQL:

如果这种方法是正确的，那么我的新构造函数nr2应该如上面所示吗？我的意思是，我应该将int字段留空还是始终从db获取所有数据：

public Object(int id, int size, int color, int author,
              string sizeString, string colorString,
              string authorString)
   {
      this.id = id;

      this.size = size;
      this.color = color;
      this.author = author;

      this.sizeString = sizeString;
      this.colorString = colorString;
      this.authorString = authorString;
   }

SQL:

---

如果添加附加字符串字段的整个想法是错误的，请引导我朝着正确的方向前进。感谢您的帮助。

您可以输入将ID解析为其相应值的项目，如：

using System;
using System.Collections.Generic;

namespace StackOverflow
{
    class Program
    {
        static void Main(string[] args)
        {
            IColorResolver colors = new ColorResolver();
            IObject demoObject1 = new Object(1, 1, 1, 1, colors);
            IObject demoObject2 = new Object(2, 3, 3, 3, colors);
            Console.WriteLine("demoObject1: {0}", demoObject1.Color.Name);
            Console.WriteLine("demoObject2: {0}", demoObject2.Color.Name);
            Console.ReadKey();
        }
    }

    public interface IObject
    {
        int Id { get; }
        ISize Size { get; set; }
        IColor Color { get; set; }
        IAuthor Author { get; set; }
    }

    public class Object: IObject
    {
        bool isDirty = false;

        readonly int id;
        int size;
        int color;
        int author;

        IColorResolver colors;

        public int Id { get { return this.id; } }
        public ISize Size { get; set; } //this would implement code like Color's
        public IAuthor Author { get; set; }//this would implement code like Color's
        public IColor Color
        {
            get { return colors.GetColor(color); }
            set
            {
                if (!this.color.Equals(value.Id))
                {
                    this.color = value.Id;
                    this.isDirty = true;
                }
            }
        }

        public Object(int id, int size, int color, int author, IColorResolver colorResolver)
        {
            this.id = id;
            this.size = size;
            this.color = color;
            this.author = author;

            this.colors = colorResolver;
        }

        // add, update, delete methods
    }

    public interface ILookupValue
    {
        int Id { get; }
        string Name { get; /*set;*/ } //no set since this is a lookup so we don't want to amend it
    }
    public interface IColor: ILookupValue
    {
        IColorResolver GetResolver();
    }
    public interface IAuthor : ILookupValue { /* ... */ }
    public interface ISize : ILookupValue { /* ... */ }

    public class Color : IColor
    {
        int id;
        string name;
        IColorResolver colors;
        public int Id { get { return this.id; } }
        public string Name { get { return this.name; } }
        public Color(int id, string name, IColorResolver colors)
        {
            this.id = id;
            this.name = name;
            this.colors = colors;
            this.colors.AddColor(this);
        }
        public IColorResolver GetResolver() { return this.colors; }
    }

    public interface IColorResolver
    {
        IColor GetColor(int id);
        void AddColor(IColor color);
    }

    public class ColorResolver : IColorResolver
    {
        IDictionary<int, IColor> colors = new Dictionary<int, IColor>();
        public ColorResolver()
        {
            /*
             in reality you'd probably pass a data layer object through 
             the constructor to fetch these values from your database 
            */
            new Color(1, "Red", this);
            new Color(2, "Green", this);
            new Color(3, "Blue", this);
        }
        public void AddColor(IColor color)
        {
            this.colors.Add(color.Id, color);
        }
        public IColor GetColor(int id)
        {
            IColor result;
            this.colors.TryGetValue(id, out result); //you could throw an exception here if not found
            return result;
        }
    }

}

---

上面代码中有大量接口的原因是这使得测试更简单；i、 e.我可以为我的任何对象创建模拟对象，并将它们传递给我，而不是我的真实对象。

Hi User283281，您的设计问题的正确答案在很大程度上取决于您希望如何使用这些类。你只需要打印出来，还是需要对它们进行完整的CRUD创建、读取、更新和删除？嗨@earthling42，我只需要打印出来，对于CRUD，我真的不需要它们。你可以通过调用ToString将整数打印成字符串。或者，如果您只是在执行类似Console.WriteLine的操作，则只需传入整数，它就会自动将其变为字符串。这不是你要找的吗？嗨，凯文斯罗威尔，不，这不是我要找的。我需要知道的是，如果我想从字典表中获取数据，例如colors，那么ID=1的color在使用join时的Name=Red。我应该将获取的颜色存储到我的对象类中，还是使用另一个包含字典数据字符串字段的类。听起来你可能想将数据库表映射到对象类。你考虑过使用ORM吗？例如：

select o.id, o.size, o.color, o.author,
       s.size as sizeS, c.color as colorS, a.name as authorS
from object o
join sizes s on o.size = s.id
join colors c on o.color = c.id
join authors a on o.author = a.id

using System;
using System.Collections.Generic;

namespace StackOverflow
{
    class Program
    {
        static void Main(string[] args)
        {
            IColorResolver colors = new ColorResolver();
            IObject demoObject1 = new Object(1, 1, 1, 1, colors);
            IObject demoObject2 = new Object(2, 3, 3, 3, colors);
            Console.WriteLine("demoObject1: {0}", demoObject1.Color.Name);
            Console.WriteLine("demoObject2: {0}", demoObject2.Color.Name);
            Console.ReadKey();
        }
    }

    public interface IObject
    {
        int Id { get; }
        ISize Size { get; set; }
        IColor Color { get; set; }
        IAuthor Author { get; set; }
    }

    public class Object: IObject
    {
        bool isDirty = false;

        readonly int id;
        int size;
        int color;
        int author;

        IColorResolver colors;

        public int Id { get { return this.id; } }
        public ISize Size { get; set; } //this would implement code like Color's
        public IAuthor Author { get; set; }//this would implement code like Color's
        public IColor Color
        {
            get { return colors.GetColor(color); }
            set
            {
                if (!this.color.Equals(value.Id))
                {
                    this.color = value.Id;
                    this.isDirty = true;
                }
            }
        }

        public Object(int id, int size, int color, int author, IColorResolver colorResolver)
        {
            this.id = id;
            this.size = size;
            this.color = color;
            this.author = author;

            this.colors = colorResolver;
        }

        // add, update, delete methods
    }

    public interface ILookupValue
    {
        int Id { get; }
        string Name { get; /*set;*/ } //no set since this is a lookup so we don't want to amend it
    }
    public interface IColor: ILookupValue
    {
        IColorResolver GetResolver();
    }
    public interface IAuthor : ILookupValue { /* ... */ }
    public interface ISize : ILookupValue { /* ... */ }

    public class Color : IColor
    {
        int id;
        string name;
        IColorResolver colors;
        public int Id { get { return this.id; } }
        public string Name { get { return this.name; } }
        public Color(int id, string name, IColorResolver colors)
        {
            this.id = id;
            this.name = name;
            this.colors = colors;
            this.colors.AddColor(this);
        }
        public IColorResolver GetResolver() { return this.colors; }
    }

    public interface IColorResolver
    {
        IColor GetColor(int id);
        void AddColor(IColor color);
    }

    public class ColorResolver : IColorResolver
    {
        IDictionary<int, IColor> colors = new Dictionary<int, IColor>();
        public ColorResolver()
        {
            /*
             in reality you'd probably pass a data layer object through 
             the constructor to fetch these values from your database 
            */
            new Color(1, "Red", this);
            new Color(2, "Green", this);
            new Color(3, "Blue", this);
        }
        public void AddColor(IColor color)
        {
            this.colors.Add(color.Id, color);
        }
        public IColor GetColor(int id)
        {
            IColor result;
            this.colors.TryGetValue(id, out result); //you could throw an exception here if not found
            return result;
        }
    }

}