FreeTDS Development Group

["James K. Lowden" <jklowden AT freetds.org>]

Michael Schodra wrote:
> 
> I try to established a DB-Link from Oracle 11g to a MSSQL 2000 database
> but it doesn't work. 
> 
> We install on Centos 5.1 (Linux 64bit).
> Our database is Oracle 11.1.0.6.0 plus bugfix 7389110 and we installed
> the "linux.x64_11gR1_gateways". I configured freetds and uinixodbc (see
> below)
> 
> I already told the unixodb folk about the problem, but they told me: ask
> the freetds folk. So I do now and I hope you can help me?
> 
> Here is my configuration and the problem. 
> 
> 
> 1. unixODBC (unixODBC-2.2.11)
> 1.1 /etc/freetds.conf
> combandb <http://forums.oracle.com/forums/> 
> host = 212.xxx.xxx.5
> port = 1433
> tds version = 8.0 
> 
> Client Charset = UTF-8
...
> UNICODE Using encoding ASCII 'ISO8859-1' and UNICODE 'UCS-2LE'

1.  When the umlauted character is passed to SQLPrepare, is it in fact
encoded as UTF-8, or is it possibly ISO 8859-1?  What is your intention?  

2.  What is the output of "tsql -C"?  When you connect with tsql, what
encoding does it report?  

> SQL = select ID, Ort, Straße from x_lt; length = 62 (SQL_NTS)

62?  There are 32 characters.  Evidently, 31 were converted to UCS-2,
giving a length of 62 = 2 * 31.  


I suspect the 'ß' cannot be converted to UCS-2 because iconv(3) is
presented with input (your SQL text) that is not encoded in the character
set it was told to expect.  The 'ß' for example is 0xE1 in 8859-1, which
is not a valid value in UTF-8.  The UTF-8 sequence is  c3 a1 (both of
which are valid 8859-1 characters). 

Because the 'ß' encoded as ISO 8859-1 cannot be interpreted as UTF-8 --
but could be interpreted, albeit incorrectly, as ISO-8859 if encoded as
UTF-8 -- I suspect that FreeTDS is responding to your freetds.conf entry
above.  It expects UTF-8, but its input is actually ISO 8859-1.  

The solution is match what FreeTDS expects to what it's given.  Either
change your locale(1) settings to use UTF-8 (so that what you type at the
terminal arrives as UTF-8) or tell FreeTDS to expect ISO 8859-1.  The
latter could be done by simply removing the "client charset" line from
freetds.conf. 

You can verify the above with a TDSDUMP log.  It will show your SQL text
as a hex dump, and at the top of the file it reports what encodings it's
using.  You should also see errors from tds_iconv about inabilty to
convert characters to be sent to the server.  

> Isql> select * from x_lt
> 
> Works well, but umlaute are missing.

When sending to the server, data encoding conversion errors result in an
error and the function fails.  When fetching data from the server, data
encoding conversion errors result in a warning, which your client tool
seems not to report.  

HTH.  

--jkl