学步园

create table Table1
(
    Id    int identity(1,1) not null,
    Name    nvarchar(20) not null,
    DepartmentId    int not null,
    Attachment1    image,
    Attachment2 image,
constraint pk_Table1 primary key(Id)
)
go
create view Table1Simple
as
  select id, Name, DepartmentCode, DepartmentName
    from Table1 T
    join sysDepartment D on T.DepartmentId=D.DepartmentId
go

将上面脚本建立的Table1表和Table1Simple视图添加到edm设计器中，然后添加一个Association，并将添加的Association关联到Table1Simple视图，问题出现了：

Error 3021: Problem in Mapping Fragment starting at line 72: Each of the following columns in table Table1Simple is mapped to multiple conceptual side properties: Table1Simple.id is mapped to <Table1Simple_Table1.Table1.id, Table1Simple_Table1.Table1Simple.id> 

 

恭喜你，这是EF4.0的一个BUG，而据官方说会在下一个发行版本中修正，值得高兴的是至少我们还有办法手工修正它：

用XML编辑器打开emdx文件，找到新建的Association，作如下修正：

<Association Name="Table1Simple_Table1">
  <End Type="Cohl.Model.Table1" Role="Table1" Multiplicity="1" />
  <End Type="Cohl.Model.Table1Simple" Role="Table1Simple" Multiplicity="1" />
</Association>
<!--我们添加一个引用约束如下所示：-->
<Association Name="Table1Simple_Table1">
  <End Type="Cohl.Model.Table1" Role="Table1" Multiplicity="1" />
  <End Type="Cohl.Model.Table1Simple" Role="Table1Simple" Multiplicity="1" />
  <ReferentialConstraint>
    <Principal Role="Table1"><PropertyRef Name="id"/></Principal>
    <Dependent Role="Table1Simple"><PropertyRef Name="id"/></Dependent>
  </ReferentialConstraint>
</Association>

 参考：http://blogs.msdn.com/b/adonet/archive/2008/12/05/table-splitting-mapping-multiple-entity-types-to-the-same-table.aspx