我可以在EF 4.1执行一个查询标？ [英] Can I execute a scalar query in EF 4.1?

问题描述

是否有可能执行使用标量值查询EF 4.1？

Is it possible to execute a scalar-valued query using EF 4.1?

我试过：

     ObjectQuery<int> query = new ObjectQuery<int>("select count(*) from myTable", _context);
     var result = query.Execute(MergeOption.NoTracking);
     return result.FirstOrDefault();

但它返回一个错误：查询语法无效。近期'*'

是执行标量值查询调用存储过程的唯一途径？

Is the only way to execute a scalar-valued query to call a stored proc?

推荐答案

在我看来，你所想的实体框架为ADO.net 2.0，而不是它是ORM。

It seems to me that you are thinking of entity framework as an "ADO.net 2.0" rather than the ORM that it is.

而不是用它来执行SQL查询，我建议你使用标准的实体框架数据容器和使用LINQ查询，如打算与实体框架。然后，它只会是这样

Rather than using it to execute SQL queries, I'd recommend using the standard entity framework Data container and using a LINQ query, as is intended with entity framework. Then it would simply be something like

    myDataContainerInstance.myTable.Count()

的ObjectQuery是不是类似于ADO.net命令并没有执行SQL语句。相反，它是用来定义针对直接对象模型的查询。因为它不是SQL中的（*）是无效的。

ObjectQuery isn't analogous to the ADO.net command and doesn't execute SQL statements. Instead it is used to define queries against the object model directly. The (*) isn't valid because it isn't SQL.

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