实体框架中的类和接口层次结构？ [英] Class and Interface hierarchies in Entity Framework?

问题描述

我有两个相关的类，它们共享一个公共接口，并且都存储在同一基础数据库表中。但是，实体框架会生成一个公共类，而我确实需要两个不同的类。我该如何解决？最好使用基类而不是接口吗？如何更改EF模型以提供映射到一个表的两个类？

I have two related classes which share a common interface and are both stored in the same underlying database table. However, the Entity Framework generates one common class, where I really need the two distinct classes. How do I resolve this? Is it best to use a base class rather than an interface? How do I change the EF model to provide two classes mapped over one table?

编辑：AccountType属性确定类的类型；用户或组。

the AccountType property determines the type of class; user or group.

一些简单的代码：

public interface IAccount
{
    string Name { get; set; }
    AccountType AccountType { get; set; }
}

public class GroupAccount : IAccount
{
    public string Name { get; set; }
    public GroupType GroupType { get; set; }
    public AccountType AccountType { get; set; }
}

public class UserAccount : IAccount
{
    public string Username { get; set; }
    public string Password { get; set; }
    public string Name { get; set; }
    public AccountType AccountType { get; set; }
}

推荐答案

是否已区分此数据？即AccountType是否定义它是哪种类型？如果是这样的话：

Is this data discriminated? i.e. does AccountType define which type it is? If so:

• EF应该从存储中创建帐户实体


• 然后创建2个子类（UserAccount和GroupAccount）


• 在帐户映射中，指定谓词添加条件
  
  
  
  
  • 拥有它映射到AccountType（存储）字段为1（或其他任何值）的UserAccount
  
  
  • 将其映射到AccountType（存储）字段为2（或其他任何内容）的GroupAccount
  
  
  • EF should create the Account entity from the storage
  • you then create 2 subclasses (UserAccount and GroupAccount)
  • in the mapping for Account, specify a predicate "add a condition"
    • have it map to UserAccount where the AccountType (storage) field is 1 (or whatever)
    • have it map to GroupAccount where the AccountType (storage) field is 2 (or whatever)

    然后，帐户类型应从Account对象中完全消失（如果没有，则取消映射）。要仅获取UserAccount记录，请使用

    The account type then should completely disappear from the Account object (unmap it if not). To get just the UserAccount records, you use

     .Accounts.OfType<UserAccount>()...
    

    在此模型中，Account类应该是抽象的。可以通过部分类添加接口材料-即在单独的文件中，定义：

    The Account class should probably be abstract in this model. The interface stuff can be added via a partial class - i.e. in a separate file, define:

    partial class Account : IAccount {
       // extra code here
    }
    

    etc

    一个合理的演练是此处。

    这篇关于实体框架中的类和接口层次结构？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！