[egenix-users] Empty strings and executedirect

[M.-A. Lemburg]

On 2007-05-14 16:01, Tommi Auvinen wrote:
> Environment: Windows client and SQLServer. Python 2.43 and mxODBC 2.0.7.
> 
>  
> 
> When I do the following insert using execute direct (C = char,
> VC=varchar etc.)
> 
> "INSERT INTO Testi (C, VC, NC, NVC) VALUES (?,?,?,?)"
> 
>  
> 
> using parameters ("", "",""; "")
> 
>  
> 
> the resulting insert is as follows
> 
> exec sp_executesql N'INSERT INTO Testi (C, VC, NC, NVC) VALUES
> (@P1, at P2, at P3, at P4)',N'@P1 char(8000), at P2 char(8000), at P3 char(8000), at P4
> char(8000) ...
> 
> ...and the data for each fields really is 8000 spaces.
> 
>  
> 
> The same using strings with one space (" ", " "," "; " ") works as
> expected: 
> 
> exec sp_executesql N'INSERT INTO Testi (C, VC, NC, NVC) VALUES
> (@P1, at P2, at P3, at P4)',N'@P1 char(1), at P2 char(1), at P3 char(1), at P4 char(1)','
> ',' ',' ',' '
> 
>  
> 
> So, am I missing something and or is this a bug? 

This looks a lot like a bug in the ODBC driver.

It seem to convert the empty data to a char(8000) column (which
is padded with spaces in SQL Server and many other database backends).

OTOH, you could also view it as bug in the way the one character
data is handled. Depends on the table schema. If this is indeed
a char(8000) column, then the one character data should also be
padded to 8000 characters.

-- 
Marc-Andre Lemburg
eGenix.com

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