NHibernate的：加入表，并从其他表中单列 [英] Nhibernate: join tables and get single column from other table

问题描述

我有以下表格：

create table Users(
 Id uniqueidentifier primary key,
 InfoId uniqueidentifier not null unique,
 Password nvarchar(255) not null
)

Create table UserInfo(
 Id uniqueidentifier primary key,
 Company nvarchar(255) not null,
 ContactPerson nvarchar(255) not null
)

和 InfoId 是一个外键引用的UserInfo（ID）。

我想这个映射到以下类：

I want to map this to the following class:

public class UserCredentials
{
    public virtual Guid Id { get; set; }
    public virtual string UserName { get; set; }
    public virtual string PasswordHash { get; set; }

    protected UserCredentials() { }
}

我想下面的映射：

I want to following mapping:

Id  --> Users(Id)
UserName --> UserInfo(Company)
PasswordHash --> Users(Password)

我尝试了以下映射：

I tried the following mapping:

<hibernate-mapping xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="urn:nhibernate-mapping-2.2">
    <class name="UserCredentials" table="Users">
    	<id name="Id" type="Guid">
    		<generator class="guid.comb" />
    	</id>

    <property name="PasswordHash" not-null="true" column="Password"/>
    <join table="UserInfo">
      <key column="Id" foreign-key="InfoId"/>
      <property name="UserName" column="Company" not-null="true" />
    </join>
  </class>
</hibernate-mapping>

但似乎＆LT;键＆GT; 元素被错误地指定（即外键属性）不做我想做的。如果我离开了外键属性，它试图加入两个表的编号列，这是不正确的。

But it seems the <key> element is incorrectly specified (the foreign-key attribute) does not do what I want. If I leave out the foreign-key attribute, it tries to join on the Id columns of both tables, which is not correct.

我不希望包括我的 UserCredentials 类的<​​code> InfoId 属性，如果有可能避免

I don't want to include an InfoId property on my UserCredentials class if it is possible to avoid it.

谁能帮我达到预期的映射？

Can anyone help me achieve the desired mapping?

推荐答案

当你想加入的realation或只是一个表像你这样在这里的基础上而不是主键，但在一些列需要使用属性-ref属性。

When you want to join in a realation or just another table like you do here based on not the primary key but on some other column you need to use the property-ref attribute.

是这样的：                                

like this:

<property name="InfoId" not-null="true" column="InfoId"/>
<property name="PasswordHash" not-null="true" column="Password"/>

<join table="UserInfo">
  <key column="Id" property-ref="InfoId"/>
  <property name="UserName" column="Company" not-null="true" />
</join>

这意味着你还需要添加InfoId你UserCredentials类，目前还没有办法MAPP关系或加入像上面使用，你必须speficy一个属性的列名（NH将使用列属性指）

This means that you need to also add InfoId to your UserCredentials class, there is currently no way to mapp a relation or a join like above by using a column name you have to speficy a property (NH will use the column that property refers to)

在一个侧面说明，外键属性有一点missleading，它只是规定，如果你让NHibernate的创建数据库模式将要生成的数据库外键的名称。

On a side note, the foreign-key attribute is a little missleading, it only specifies the name of the database foreign key that will be generated if you let nhibernate create the database schema.

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