Access SQL Server Data as OData Feeds in Tableau

The CData API Server, when paired with the ADO.NET Provider for SQL Server (or any of 200+ other ADO.NET Providers), provides SQL Server data as OData Web services. This article will explain how to use the API Server to provide the underlying connectivity to SQL Server data in Tableau's business intelligence tool.

Set Up the API Server

Follow the steps below to begin producing secure SQL Server OData services:

Deploy

The API Server runs on your own server. On Windows, you can deploy using the stand-alone server or IIS. On a Java servlet container, drop in the API Server WAR file. See the help documentation for more information and how-tos.

The API Server is also easy to deploy on Microsoft Azure, Amazon EC2, and Heroku.

Connect to SQL Server

After you deploy the API Server and the ADO.NET Provider for SQL Server, provide authentication values and other connection properties needed to connect to SQL Server by clicking Settings -> Connections and adding a new connection in the API Server administration console.

Connecting to Microsoft SQL Server

Connect to Microsoft SQL Server using the following properties:

• Server: The name of the server running SQL Server.
• User: The username provided for authentication with SQL Server.
• Password: The password associated with the authenticating user.
• Database: The name of the SQL Server database.

Connecting to Azure SQL Server and Azure Data Warehouse

You can authenticate to Azure SQL Server or Azure Data Warehouse by setting the following connection properties:

• Server: The server running Azure. You can find this by logging into the Azure portal and navigating to "SQL databases" (or "SQL data warehouses") -> "Select your database" -> "Overview" -> "Server name."
• User: The name of the user authenticating to Azure.
• Password: The password associated with the authenticating user.
• Database: The name of the database, as seen in the Azure portal on the SQL databases (or SQL warehouses) page.

When you configure the connection, you may also want to set the Max Rows connection property. This will limit the number of rows returned, which is especially helpful for improving performance when designing reports and visualizations.

You can then choose the SQL Server entities you want to allow the API Server to access by clicking Settings -> Resources.

Additionally, click Settings -> Server and set the Default Format to XML (Atom) for compatibility with Tableau.

Authorize API Server Users

After determining the OData services you want to produce, authorize users by clicking Settings -> Users. The API Server uses authtoken-based authentication and supports the major authentication schemes. Access can also be restricted based on IP address; by default only connections to the local machine are allowed. You can authenticate as well as encrypt connections with SSL.

Create Real-Time SQL Server Data Visualizations

Follow the steps below to create data visualizations based on the remote SQL Server data:

1. In Tableau, select 'Connect to data'. In the 'On a server' section, click OData.

   

2. In the resulting wizard, enter the URL of the OData endpoint for the API Server. Append the name of the table you want to access to the OData entry URL. For example:

   https://your-server/api.rsc/Orders
3. Select the 'Use a Username and Password' option and enter the username and password of a user who has access to the API Server.

4. Tableau uses the table metadata exposed by the API Server to detect dimension and measure columns.

   

5. To view the SQL Server data, right-click under the table name in the Data section of the dashboard and select the View Data option. The SQL Server data will appear in Tableau.