How to return values from a dynamic SQL Stored Pro

问题:

I have a Stored Procedure which executes some dynamic SQL. I want to use this Stored Procedure in entity framework 4, but when I try to create a complex type the procedure returns no columns. Is there any way I can force it to return my values and get the entity framework to receive them? Here is a much-simplified example of what I want to do:

CREATE PROCEDURE sp_calculatesalary(@EmployeeId as int)
begin
    declare dynsql as varachar(500)
    @dynsql='Select @Salary=Salary,@UserName=Username from employee
            where EmployeeId='+cast(@EmployeeId as varchar)+ ''
    exec(@dynsql)
    select @Salary, @UserName
end

But this does not work. Please help me out. Basically, I want to use a Stored Procedure to execute dynamic SQL and return the values to the entity framework.

回答1:

Perhaps you could consider parameterized SQL, if you must do dynamic queries:

CREATE PROCEDURE sp_calculatesalary(@EmployeeId as int)  
as 
begin   
    declare @dynsql varchar(500)   
    declare @params nvarchar(500)
    declare @salary money
    declare @username varchar(50)
    set @dynsql='Select @sal=Salary,@usernm=Username from employee where EmployeeId=@empID'   
    set @params='@empID int, @sal money OUTPUT, @usernm varchar(50) OUTPUT'
    exec sp_executesql @dynsql, @params, @empID=@EmployeeID, @sal=@salary OUTPUT, @usernm = @username OUTPUT
    SELECT @salary, @username
end

回答2:

try this

CREATE PROCEDURE sp_calculatesalary(@EmployeeId as int)   
AS
   DECLARE @dynsql VARCHAR(500)=' Salary,Username FROM employee WHERE EmployeeId=@empID'    
   EXEC sp_executesql @dynsql,'@empID INT',@empID=@EmployeeID
   SELECT 1 AS salary,2 AS username

Believe me. That is enough.

Or you can simply create a complex type based on your query result , and then use collection of the complex type as your query result.

回答3:

add following line at beginning of your SP

SET FMTONLY OFF

回答4:

Try the below script this is working good.

BEGIN TRAN

DECLARE @Result varchar(max),@Table varchar(max),@Column varchar(max)

set @Column= 'CategoryName,CategoryID'
set @Table='Category'
set @Result= ' select ' + @Column + ' from '+@Table

exec(@Result)


ROLLBACK

回答5:

well, i think this is what you are looking for:

create procedure sp_calculatesalary
    @employeeId int
as
    declare @sql nvarchar(max);
    @sql='select salary, username from employee
            where employeeId=' + cast(@employeeId as nvarchar(10));

    declare @t table (salary float, username varchar(50));
    insert into @t exec(@sql);

    select salary, username from @t;
return

this will generate a public partial class sp_calculatesalary_Result in entity framework based DAL.

回答6:

have you tried giving aliases to your last Select:

select @Salary as Salary, @UserName as UserName

回答7:

Well, if EF cannot recognize what your stored procedure must return then create your complex type ahead of time. You can create a complex type by right clicking any where on the model and and add a complex type. Next when you import your stored procedure, you can choose your complex type from the dropdown.