如何建模这个实体

Question

我正在为一家商店创建一个应用程序,客户分为两组:接收者和付款人.

1)许多接收者可以与同一个付款人相关.2)付款人本身可以是接收者,因此他只与一个接收者有关

到目前为止,我的代码如下所示:

public class Receiver
{
    [Key]
    public int ReceiverId { get; set; }
    public string Name { get; set; }
    [Required]
    public int PayerId { get; set; }
    public virtual Payer Payer { get; set; }
}

public class Payer
{
    [Key]
    public int PayerId { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Receiver> Receivers { get; set; }
}

但是我需要让用户同时创建一个同时也是接收者的新付款人,因此Receivers集合只有一个元素.为此,我想使用一个复选框,它将被转换为数据库中的新列(IsAlsoReceiver).

我正在使用MVC脚手架来创建视图,它创建了两个用于添加Receiver的视图和另一个用于添加Payer的视图.当用户需要也是接收者的付款人时,他必须在两个视图中添加实体; 在这种情况下可以简化吗？

我要求一个明智的方法来做到这一点.

Answer 1

我想你错过了一个抽象层.当您构建一个特定大小的项目(我认为您已达到的大小)时,您需要每个组件(数据层,逻辑层和视图)来查看不同的模型.

数据访问层(DAL)具有域模型

逻辑层或API具有数据传输对象

视图具有视图模型

为了便于构建和理解,我只使用域模型和视图模型.

对于您当前的问题,我会像这样构建它:

//this is the view model
//The user sees this model
public class Person {
    public string Name { get; set; }
    public bool IsReceiver { get; set; }
    public bool IsPayer { get; set; }
}
//these are the domain models
//The database uses these models
public class Receiver {
    [Key]
    public int ReceiverId { get; set; }
    public string Name { get; set; }
    [Required]
    public int PayerId { get; set; }
    public virtual Payer Payer { get; set; }
}
public class Payer {
    [Key]
    public int PayerId { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Receiver> Receivers { get; set; }
}

public class AccountController {

    //create a view for the Person View Model
    //this is your abstraction
    public void SignUp(Person p) {
        //create models for the repository
        Payer payer = new Payer() {
            Name = p.Name
        };
        Receiver receiver = new Reciever() {
            Name = p.Name
        };

        //if the payer is his own receiver:
        Receiver.Payer = payer;

        //if the payer is his own receiver:
        Payer.Receivers.Add(receiver);


        //create for each depending upon some condition
        //I've just allowed the user to select whether he is a payer
        //based upon a checkbox on the form I suppose
        if (p.IsPayer) {
            db.Payers.Add(payer);
        }
        if (p.IsReceiver) {
            db.Receivers.Add(receiver);
        }

        db.SaveChanges();
    }
}