我想将标量函数的值包含为实体的只读属性,因为我可以在过滤器中包含该值,这是可能的吗?
答案 0 :(得分:1)
解决方案是添加一个DefiningQuery,如下例所示:
<!-- SSDL content -->
<EntitySet Name="Emp" EntityType="TestModel.Store.Emp" >
<DefiningQuery>
SELECT EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO, dbo.MyFunc(DEPTNO) AS DNAME FROM EMP
</DefiningQuery>
</EntitySet>
<EntityType Name="Emp">
<Key>
<PropertyRef Name="EMPNO" />
</Key>
<Property Name="EMPNO" Type="int" Nullable="false" />
...
<Property Name="DNAME" Type="varchar" MaxLength ="20" />
</EntityType>
...
<!-- CSDL content -->
...
<EntityType Name="Emp">
<Key>
<PropertyRef Name="EMPNO" />
</Key>
<Property Name="EMPNO" Type="Int32" Nullable="false" />
...
<Property Name="DNAME" Type="String" MaxLength="20" Unicode="false" FixedLength="false" />
</EntityType>
<!-- C-S mapping content -->
...
<ScalarProperty Name="EMPNO" ColumnName="EMPNO" />
...
<ScalarProperty Name="DNAME" ColumnName="DNAME" />
...
用法示例:
using(TestEntities4 db = new TestEntities4()) {
var q = from e in db.Emp where e.DNAME == "RESEARCH" select e;
}
答案 1 :(得分:0)
在EF4中,您可以在同一名称空间中定义与Entity Framework类同名的部分类,并为其添加只读属性。我刚刚这样做是为了将连接的Entity对象的描述公开为原始对象的只读属性。
namespace same.as.the.data.model
{
public partial class Order
{
public string CustomerName
{
get { return Customer.Name; }
}
}
}