As Tableau Desktop does not yet have a native data connection to Cassandra, your best bet is to go with a DSN connection here.
There are two parts to configuration:
1. Create the DSN in Windows
2. Use the Other Databases (ODBC) data connector in Tableau to connect to Cassandra using the DSN you set up in Windows
Create the DSN in Windows
Page 10 of the Simba Cassandra ODBC Install Guide includes the instructions you'll need to configure the DSN using the Windows ODBC Administrator. For Username & Password, you'll need to touch base with your Cassandra Database Administrator. He or she should be able to provide you with the appropriate log in credentials. If you are the Database Administrator, use the username & password you normally use to log into the database.
Connect using DSN in Tableau
After you have created the DSN, you can move onto connecting to your database using Tableau.
- Go to Data > New Data Source
- Click More... under "To a Server"
- Scroll to the bottom and select Other Databases (ODBC)
- Select the DSN you configured from the drop down menu under "Connect Using"
- Click Connect
- Click Sign In
When working with ODBC connections like this it is important to keep in mind that success often varies and full compatibility with Tableau features cannot be guaranteed. Extracting the data source, after connection, typically will restore most, if not all, of Tableau functionality.
I might also suggest reviewing the following documentation on working with and tuning ODBC data connections, which may help you to address any warnings, errors, or functional limitations you might encounter:
Tableau and ODBC: http://kb.tableausoftware.com/articles/knowledgebase/tableau-and-odbc
Customizing and Tuning ODBC Connections: http://kb.tableausoftware.com/articles/knowledgebase/customizing-odbc-connections
Tableau Data Extract API: http://onlinehelp.tableausoftware.com/current/pro/online/en-us/help.htm#extracting_TDE_API.html