由网友(偶尔善良)分享简介：我有两个表：地址和联系它们连接上的ContactID（在联系）。这两个表在我的实体数据模型实体（EF 4.0），我不wan't对其进行修改。I have two tables: Address and Contact which are joined on contactID (in Contact). Both o...

我有两个表：地址和联系它们连接上的ContactID（在联系）。这两个表在我的实体数据模型实体（EF 4.0），我不wan't对其进行修改。

I have two tables: Address and Contact which are joined on contactID (in Contact). Both of these tables have entities in my Entity data model (EF 4.0) and I do not wan't to modify them.

我想创建一个包含两个实体的信息的新实体。

I do want to create a new entity that contains information from both entities.

我所做的，到目前为止：

What I did so far:

在CSDL：

<EntityContainer...>
    <EntitySet Name="AddressTest" EntityType="WebGearsModel.Test" />
    <EntitySet Name="ContactTest" EntityType="WebGearsModel.Test" />
</EntityContainer>

<EntityType Name="Test">
  <Key>
    <PropertyRef Name="addressID" />
  </Key>
  <Property Type="Int32" Name="addressID" Nullable="false" annotation:StoreGeneratedPattern="Identity"  />
  <Property Type="Int32" Name="contactID" Nullable="false"  />
  <Property Type="String" Name="firstName" Nullable="false" MaxLength="30" FixedLength="false" Unicode="false" />
  <Property Type="String" Name="emailAddress" Nullable="false" MaxLength="150" FixedLength="false" Unicode="false" />
</EntityType>

在我的C-S映射：

<EntitySetMapping Name="AddressTest">
  <EntityTypeMapping TypeName="WebGearsModel.Test">
    <MappingFragment StoreEntitySet="Address">
      <ScalarProperty Name="addressID" ColumnName="addressID" />
      <ScalarProperty Name="contactID" ColumnName="contactID" />
      <ScalarProperty Name="firstName" ColumnName="firstName" />
    </MappingFragment>
  </EntityTypeMapping>
</EntitySetMapping>

<EntitySetMapping Name="ContactTest">
  <EntityTypeMapping TypeName="WebGearsModel.Test">
    <MappingFragment StoreEntitySet="Contact">
      <ScalarProperty Name="contactID" ColumnName="contactID" />
      <ScalarProperty Name="emailAddress" ColumnName="emailAddress" />
    </MappingFragment>
  </EntityTypeMapping>
</EntitySetMapping>

我收到的错误是：

The error I'm receiving is:

在映射碎片问题开始   在行150：必须为指定映射   所有关键特性   的（ContactTest.addressID）   EntitySet的ContactTest。

Problem in mapping fragments starting at line 150:Must specify mapping for all key properties (ContactTest.addressID) of the EntitySet ContactTest.

我怎么映射从联系人实体的AddressID时，它不会在该实体存在吗？我想我需要某种关联，但我不知道该如何去做......请记住，我不希望有改变我现有的地址和联系的实体。

How am I supposed to map an AddressID from the Contact entity when it doesn't exist in that entity? I guess I need some sort of association but I'm unsure how to go about it... Remember, I don't want to have to modify my existing Address and Contact entities.

推荐答案

记住一个实体的定义：

这是不被定义的一个对象的   属性，而是由一个线程   连续性和其身份。

An object that is not defined by its attributes, but rather by a thread of continuity and its identity.

每一个实体必须拥有的东西，唯一标识;关键。但是，你似乎是试图从只有一个按键，它提供了地址的一致认同，但不接触单个物理类型定义了两种类型的实体。这违反了实体的规则，使得ContactTest概念无效。

Every "entity" must have something that uniquely identifies it; a key. However, you appear to be trying to define two types of entities from a single physical type that has only one key that provides a consistent identity for addresses, but not contacts. That violates the rules of an Entity, making the ContactTest concept invalid.

由于底层物理类型，测试，定义了一个关键属性， addressID ，所有的EntitySet的该类型派生必须映射该属性，以符合定义的实体规则。维护状态的一致性是不可能的，否则。

Since the underlying physical type, Test, defines a key property, addressID, all EntitySet's derived from that type must map that property to conform to the rules defining an Entity. Maintaining consistency of state is impossible otherwise.