在实体调用用户自定义函数框架4 [英] Calling user defined functions in Entity Framework 4

问题描述

我在它返回一个有点SQL Server 2005数据库用户定义的函数。我想通过实体框架调用这个函数。我一直在寻找周围并没有多少运气。

I have a user defined function in a SQL Server 2005 database which returns a bit. I would like to call this function via the Entity Framework. I have been searching around and haven't had much luck.

在LINQ to SQL中，这是可耻的容易，我想补充的功能数据上下文模型，我可以这样称呼它。

In LINQ to SQL this was obscenely easy, I would just add the function to the Data context Model, and I could call it like this.

bool result = FooContext.UserDefinedFunction(someParameter);

使用实体框架

，我已经加入的功能我的模型，它SomeModel.Store \\存储过程下出现在模型浏览器。

Using the Entity Framework, I have added the function to my Model and it appears under SomeModel.Store\Stored Procedures in the Model Browser.

该模型生成任何code的作用，为.edmx文件的XML包含：

The model has generated no code for the function, the XML for the .edmx file contains:

<Function Name="UserDefinedFunction" ReturnType="bit" Aggregate="false" BuiltIn="false" NiladicFunction="false" IsComposable="true" ParameterTypeSemantics="AllowImplicitConversion" Schema="dbo">
    <Parameter Name="someParameter" Type="int" Mode="In" />
</Function>

我能得到最接近的是这样的：

The closest I could get was something like this:

bool result = ObjectContext.ExecuteFunction<bool>(
    "UserDefinedFunction",
    new ObjectParameter("someParameter", someParameter)
).First();

但我得到了以下错误消息：

But I got the following error message:

该FunctionImport
  UserDefinedFunction不能
  在容器FooEntities'找到。

The FunctionImport 'UserDefinedFunction' could not be found in the container 'FooEntities'.

名称已被更改，以保护无辜。

Names have been changed to protect the innocent.

的 tldr：我如何使用调用实体框架4.0标量值用户自定义函数的

推荐答案

我终于工作了。：D对于标量函数可以追加FROM {1}条款

I have finally worked it out :D For scalar functions you can append the FROM {1} clause.

bool result = FooContext.CreateQuery<bool>(
    "SELECT VALUE FooModel.Store.UserDefinedFunction(@someParameter) FROM {1}",
    new ObjectParameter("someParameter", someParameter)
).First();

这肯定是使用LINQ to SQL在EF的情况。

This is definitely a case for using LINQ to SQL over EF.

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