Re: Message bug in libgda

[Brian Bruns <camber ais org>]

On Tue, 10 Oct 2000, Holger Thon wrote:

> Hi!
> 
> On Sun, Oct 08, 2000 at 01:38:15PM -0400, Brian Bruns wrote:
> > 
> > TDS is the name of the protocol (Tabular DataStream). The library would be
> > either dblib or ctlib (together known as OpenClient). 
> > 
> > The only possible problem is most people aren't familiar with the protocol
> > name (much as if you listed the oracle client under 'SQLNet').  So  
> > perhaps the documentation should have listings for both Sybase and MS SQL
> > and point them at the gda-tds-provider.
> > 
> 
> I don't know how cvs handles symlinks, because i've never used them before.
> 
> On freetds there would remain two technical question about the tds protocol
> versions: In the FAQ i read you need to compile it with tds v4.2 support in 
> order to access MS SQL or Sybase prior to 10.0.0. 
> 
> 1.) If someone would use it with the gda-tds-srv (or whatever it
>     is called later), he could just use both MS SQL and Sybase with the 
>     provider if he chose v4.2 protocol, right?

Both Sybase and Microsoft continue to support the 4.2 protocol.  If you
send a 4.2 login packet the server will communicate using 4.2, but...

> 2.) Would Sybase after version 10.0.0 be accessible via the old tds protocol
>     (i.e. 4.2), too, or is e.g. tds 7.0 not downwards compatible?
> 

TDS 5.0 implements some special Sybase functionality such as access to
server-side cursors and dynamic placeholders.

TDS 7.0 implements some special MS SQL functionality most notably unicode
support and long (more than 255 chars) char and varchar datatypes.

neither vendor supports the others enhancements (a lot of NIH syndrome i
guess).

The protocol level is definable in 4 ways. You can compile it in with the
--with-tdsver option on configure.  You can define an environment variable
TDSVER prior to running your program. You can define certain servers to
use a particular version by putting in inplace of 'ether'  in the
interfaces file (the interfaces file is used by sybase to connect a 
symbolic server name with a host/port) like:

...
myserver
	query tcp tds4.2 127.0.0.1 4000
...

And lastly, you can do it in the program with calls to dbsetversion() and
its ctlib counterpart. (This is the only one that the Sybase OpenClient
drivers support BTW).

> 
> Ciao,
> 
>   Holger Thon
> 

Cheers,

Brian