从SQL触发器启动时，可执行文件无法写入文本文件

Question

I currently have a trigger named Writer set on my table DEF_TEST that, after an update or insert, runs an executable that writes to a text file. It looks like this :

ALTER TRIGGER [dbo].[Writer] ON [dbo].[DEF_TEST]
AFTER INSERT, UPDATE
AS 
BEGIN
    BEGIN TRY
        DECLARE @cmd as varchar(500)
        SET @cmd = 'Path\Write_To_File.exe'
        EXEC dbo.RunCMD @cmd

        --Insert ok if no error are thrown
        INSERT INTO DEF_TEST(ErrorLine, ErrorMessage)
        VALUES('ok', 'ok')
    END TRY
    BEGIN CATCH
        INSERT INTO DEF_TEST(ErrorLine, ErrorMessage)
        VALUES(ERROR_LINE(), ERROR_MESSAGE())
    END CATCH
END

Write_To_file.exe is essentially this:

Imports System.IO

Module Main
    Sub Main()
        Try
            File.WriteAllText(".\test.txt", "test", System.Text.Encoding.UTF8)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub
End Module

This code works, because if I change the code of "Write_To_File.exe" to just print to a console, the trigger works perfectly. When I try to run "Write_To_File.exe" by double-clicking on it, it's able to create and write in "test.txt". But when the trigger launches "Write_To_File.exe" and tries to write in "test.txt", it just does nothing. No task launch in the task manager, no error thrown from the trigger.

What's weird is any code after trying to write in "test.txt" doesn't work. For example, if I try to print to a console it doesn't work.

I don't think the problem is with the file security as the SQL Server has total control on the entire folder.

Am I missing something obvious? Is there a way to see what happens step by step when "Writer" triggers?

Answer 1

I found the problem!

I finally logged the .exe and he threw an exception, namely "Access to the path 'C:\\windows\\system32\\test.txt' is denied." . It's because I was trying to write to ".\\test.txt", and because the sql server was executing the .exe from system 32 and not from the folder where the executable is, he was trying to write the test file in an unauthorized path (system32). I just specified the exact path of the text file in my program (C:\\Path.....\\test.txt) and everything worked fine. :)