nhibernate 多对多映射 - 映射表中的附加列? [英] nhibernate many-to-many mapping - additional column in the mapping table?

问题描述

我有以下映射定义:

  <class name="Role" table="Role" optimistic-lock="version" >

    <id name="Id" type="Int32" unsaved-value="0" >
      <generator class="native" />
    </id>

    <property name="RoleName" type="String(40)" not-null="true" />

    <bag name="UsersInRole" generic="true" lazy="true" cascade="all" table="UserRoles" >
      <key  column="RoleId" />
      <many-to-many column="UserId" class="SystemUser, Domain"/>
    </bag>

和

<id name="Id" type="Int32" unsaved-value="0" >
  <generator class="native" />
</id>
<property name="UserName" type="String(40)" not-null="true" unique="true" />

此映射生成映射表 UserRoles，其中有两列 - RoleId 和 UserId.

This mapping generates mapping table UserRoles, which has two columns - RoleId and UserId.

但是，我想为该关系添加额外的属性 - 即一些定义关系状态的枚举值以及有效的开始和;结束日期.

However, I'd like to add extra attributes to that relation - i.e. some enum values defining state of the relation as well as effective start & end dates.

是否可以在 nhibernate 中进行，或者我是否需要在此处添加其他类并将关系 m-to-m 更改为 2 个关系 [user] 1-to-m [user_role] m-to-1 [role] ?

Is it possible to do in nhibernate or do I need to add additional class here and change relation m-to-m into 2 relations [user] 1-to-m [user_role] m-to-1 [role] ?

推荐答案

您需要添加一个额外的类，例如UserRole，在代码中保留附加属性.

You need to add an extra class, e.g. UserRole, in code to keep the additional properties.

当涉及到映射时，可以将其映射为您提到的类.但我也认为它可以映射为角色映射中的复合元素:

When it comes to mapping this can be mapped as a class as you mentioned. But I also think it can be mapped as a composite-element in the Role mapping:

<set name="UsersInRole" lazy="true" table="UserRoles" >
  <key  column="RoleId" />
  <composite-element class="UserRole">
     <many-to-one name="User" column="UserId" not-null="true"/>
     <propery name="RelationState" not-null="true"/>
     <propery name="StartDate" not-null="true"/>
     <propery name="EndDate" not-null="true"/>
  </composite-element>
</set>

所有属性都必须不为空，因为它们已成为 UserRoles 表主键的一部分.有关更多信息，请参阅:

All properties must be not-null, because they're become part of the primary keys of the UserRoles table. For more information see:

• Nhibernate 复合元素映射
• 7.2.依赖对象的集合

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