FreeTDS Development Group

["Lowden, James K" <LowdenJK AT bernstein.com>]

Title: [freetds] Re: dbwritetext()

On Wed, 25 Oct 2000, Christopher Weimann wrote:           
        Should I be using ct-lib instead?

On Wed, 25 Oct 2000, Brian Bruns wrote:
        Does MS support bulk copy and write text through ODBC or OLE-DB?

Christopher,

You're right, db-lib and ct-lib are both APIs to the underlying TDS protocol that is supported by Sybase and Microsoft.  Microsoft documentation barely mentions db-lib or TDS, except with regard to bulk-copy services. 

Microsoft advocates its newer protocols and APIs (and OSes).  From http://www.microsoft.com/sql/productinfo/sysreq.htm (system requirements for SQL Server 2000):

========
Client Support

*       Windows 95, Windows 98, Windows Me, Windows NT Workstation 4.0, and Windows 2000 Professional are supported.

*       UNIX, Apple Macintosh, and OS/2 require Open Database Connectivity (ODBC) client software from a third-party vendor.

I can just hear the resounding shock Shock! that FreeTDS isn't mentioned.  Betcha it works, though, or will soon.  Question for list: Has anyone tried? 

========

Microsoft has enough ornery corporate clients with 10-year-old db-lib (and some ct-lib) applications that they keep supporting TDS with service packs.  As Brian indicates, the support seems to be in the "reluctant but necessary" category.  I'd also say it's probably too easy not to do. 

Opinion:  Db-lib *is* a nice API.  It is simple, which means it works for lots of stuff and not for a few things.  Sybase came up with ct-lib to address the shortcomings (like multiplexing the connections), but ct-lib isn't light-years ahead.  It's just  a little better, for those who want to fully exploit Sybase.  ODBC is a lot of gobbledygook when it's not sheer tourture.  End opinion. 

AFAIK, TDS and ODBC are session-level protocols, while db-lib, ct-lib, and ODBC are APIs.  (Microsoft frequently doesn't distinguish between a protocol and an API, and ODBC is one example.)  In theory, the db-lib library could use the ODBC protocol to get the bits through the pipe.  That would be one way to keep db-lib programs cooking if MS dropped TDS support one day. 

Microsoft is tied to TDS by its customers, not its technology.  They support bulk-copy through ODBC and SQL-DMO (the COM object(s) that talk to OleDb).   SQL Server also has a "bulk insert" SQL function that tells the *server* where the file is; SQL Server then reads in the data over the file system. 

(http://larr.unm.edu/~owen/SQLBOL70/html/ba-bz_9.htm) But, it requires the administrator privileges, making it unsuitable for most production applications. 

Hope this helps. 

Regards, 

--jkl