FreeTDS Development Group

[jklowden AT schemamania.org]

On Mon, Apr 19, 2010 at 11:00:05PM +0200, Frediano Ziglio wrote:
> Il giorno lun, 19/04/2010 alle 12.04 -0400, jklowden AT schemamania.org ha
> scritto:
> > > > ??  For db-lib connections, the server converts varchar(max) to TEXT 
> > > > (type 35).  Then the db-lib API can deal with it either by binding it 
> > > > as a string or with dbmoretext().  
> > > 
> > > Yes, this is true with MS dblib cause MS dblib use only protocol 4.2. We
> > > support protocol up to 7.1 under dblib :)
> 
> Yes, cause you are using protocol 7.1 which does not support
> varchar(max) so this type is returned as text :)
> Protocol 7.2 support varchar(max) with different byte encoding.

I see, finally.  I found this code in tds_connect_and_login():

        /* disable tds9 if iconv wanted, currently not supported */
        if (IS_TDS72(connection) && tds->use_iconv)
                connection->tds_version = 0x701;

So, no matter how I set TDSVER, I never get more than 7.1.  :-(

I've come to understand that client encoding is properly a binding step: the 
library should always keep an original as-received copy of the data, and only 
when asked to convert to a "string" does it need to consult iconv.  That's 
the only way to support binary bindings, and the best way to support UTF-16 
on a TDS 7+ connection.  

Not easy to fix, though.  

--jkl