Access CSV Data as OData Feeds in Tableau

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

Set Up the API Server

Follow the steps below to begin producing secure CSV 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 CSV

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

The DataSource property must be set to a valid local folder name.

Also, specify the IncludeFiles property to work with text files having extensions that differ from .csv, .tab, or .txt. Specify multiple file extensions in a comma-separated list. You can also set Extended Properties compatible with the Microsoft Jet OLE DB 4.0 driver. Alternatively, you can provide the format of text files in a Schema.ini file.

Set UseRowNumbers to true if you are deleting or updating in CSV. This will create a new column with the name RowNumber which will be used as key for that table.

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 CSV 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 CSV Data Visualizations

Follow the steps below to create data visualizations based on the remote CSV 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/Customer
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 CSV data, right-click under the table name in the Data section of the dashboard and select the View Data option. The CSV data will appear in Tableau.