What is TDS25.04.26

In the context of your MSSQL Docker server, **TDS stands for Tabular Data Stream**.

**What is TDS?**

TDS is a proprietary network protocol developed by Sybase and later adopted and extended by Microsoft for **SQL Server**. It's the protocol used for communication between a SQL Server client application (like SQL Server Management Studio, Azure Data Studio, a custom application, or even your Dockerized MSSQL instance itself if it needs to talk to another SQL Server) and the SQL Server database engine.

**Key Functions of TDS:**

*   **Data Transfer:** It defines how data is formatted and exchanged between the client and server. This includes sending SQL queries and receiving result sets.
*   **Commands:** It handles the transmission of commands, such as `SELECT`, `INSERT`, `UPDATE`, `DELETE`, and stored procedure calls.
*   **Metadata:** It's used to transmit metadata, like database schema information, data types, and error messages.
*   **Authentication and Session Management:** TDS is also involved in the initial authentication process and managing the communication session.

**Why is it relevant to your MSSQL Docker server?**

When you run MSSQL in Docker, you're essentially running the SQL Server database engine in a container.

1.  **Clients Connect via TDS:** Any application or tool that needs to connect to your Dockerized SQL Server will use the TDS protocol over the network. This includes:
    *   **Development Tools:** SQL Server Management Studio (SSMS), Azure Data Studio.
    *   **Applications:** Your custom-built applications (web apps, desktop apps) that interact with the database.
    *   **Other Databases/Services:** If you have other services that need to query your SQL Server, they will use TDS.

2.  **Port Exposure:** For clients to connect to your Dockerized SQL Server, you need to expose the TDS port. The default TDS port for SQL Server is **1433**. When you set up your Docker container, you'll typically map a host port to the container's internal port 1433. For example:
    ```bash
    docker run -e "ACCEPT_EULA=Y" -e "MSSQL_SA_PASSWORD=YourStrongPassword" \
       -p 1433:1433 \
       -d mcr.microsoft.com/mssql/server:latest
    ```
    Here, `-p 1433:1433` maps your host's port 1433 to the container's port 1433, allowing clients to connect to `localhost:1433` (or your Docker host's IP and port 1433) using the TDS protocol.

3.  **Internal Communication:** While less common for a single instance, if your Dockerized SQL Server were part of a cluster or needed to communicate with other SQL Servers, TDS would be the protocol used.

**In short:** TDS is the language your MSSQL server in Docker "speaks" to all its clients. When you connect to it, you're using a client library that implements TDS to send commands and receive data. The port (usually 1433) you expose is where the TDS communication happens.

https://learn.microsoft.com/en-us/sql/relational-databases/security/networking/tds-8?view=sql-server-ver16

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What is TDS25.04.26

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