Tabular Data Stream - SQL Server

Tabular Data Stream (TDS) is a protocol used by Microsoft SQL Server to communicate with its client applications. TDS is a binary protocol that allows for efficient and secure communication between SQL Server and its clients. In this example, we will look at how TDS is used in SQL Server to retrieve data from a table.

Let's say we have a table named "Employees" in our SQL Server database, with the following structure and data:

CREATE TABLE Employees (

   ID INT PRIMARY KEY,

   Name VARCHAR(50),

   Age INT,

   Department VARCHAR(50)

);

INSERT INTO Employees VALUES (1, 'John', 30, 'Sales');

INSERT INTO Employees VALUES (2, 'Mary', 25, 'Marketing');

INSERT INTO Employees VALUES (3, 'Bob', 40, 'IT');

Now, let's assume that we have a client application that needs to retrieve data from the "Employees" table. The client application sends a request to SQL Server using the TDS protocol. The request may look something like this:

SELECT * FROM Employees WHERE Department = 'Sales'

When SQL Server receives this request, it processes it and generates a response in a tabular format, which is then sent back to the client application using the TDS protocol. The response may look something like this:

ID | Name | Age | Department

---+------+-----+-----------

1  | John | 30  | Sales

In this example, the response contains only one row, because there is only one employee in the "Sales" department. If there were more employees in the department, the response would contain multiple rows.

The response is sent back to the client application in a binary format, which the client application can then parse and process as needed. The TDS protocol also supports other types of requests, such as updates, inserts, and deletes, which can be used to modify the data in the database.

TDS is a critical component of the SQL Server architecture, allowing for efficient and secure communication between client applications and the server. It is used extensively in SQL Server to retrieve, modify, and manage data in a database.