Tabular Data Stream (TDS) is an application layer protocol used to transfer data between a database server and a client. It was initially designed and developed by Sybase Inc. for their Sybase SQL Server relational database engine in 1984, and later by Microsoft in Microsoft SQL Server.
Communication protocol | |
Abbreviation | TDS |
---|---|
Purpose | Database |
Developer(s) | Sybase Inc., Microsoft |
Introduction | 1984 |
OSI layer | Application layer (7) |
Port(s) | TCP/1433 |
During the early development of Sybase SQL Server, the developers at Sybase perceived the lack of a commonly accepted application level protocol to transfer data between a database server and its client. In order to encourage the use of its products, Sybase promoted the use of a flexible pair of libraries, called netlib
and db-lib
, to implement standard SQL. A further library was included in order to implement "Bulk Copy" called blk
. While netlib
's job is to ferry data between the two computers through the underlying network protocol, db-lib
provides an API to the client program, and communicates with the server via netlib
. db-lib
sends to the server a structured stream of bytes meant for tables of data, hence a Tabular Data Stream. blk
provides, like db-lib
, an API to the client programs and communicates with the server via netlib
.
In 1990 Sybase entered into a technology-sharing agreement with Microsoft which resulted in Microsoft marketing its own SQL Server — Microsoft SQL Server — based on Sybase's code. Microsoft kept the db-lib
API and added ODBC. (Microsoft has since added additional APIs.) At about the same time, Sybase introduced a more powerful successor to db-lib
, called ct-lib
, and called the pair Open Client. db-lib
, though officially deprecated, remains in widespread[quantify] use.
The TDS protocol comes in several varieties, most of which had not been openly documented because they were regarded[by whom?] as proprietary technology. The exception was TDS 5.0, used exclusively by Sybase, for which documentation is available from Sybase.[1] This situation changed when Microsoft published the TDS specification in 2008,[2] as part of the Open Specification Promise.
The FreeTDS team has developed a free native-library implementation of the TDS protocol,[3] licensed under the LGPL license. WireShark has a protocol decoder for TDS.[4]
Oracle Corporation provides Oracle Net - software analogous to TDS.[5]
Oracle Net is analogous to the SQL Server Tabular Data Stream (TDS) transport facility.