How to connect PolyBase to Excel Online

PolyBase for SQL Server allows you to query external data by using the same Transact-SQL syntax used to query a database table. When paired with the CData ODBC Driver for Excel Online, you get access to your Excel Online data directly alongside your SQL Server data. This article describes creating an external data source and external tables to grant access to live Excel Online data using T-SQL queries.

NOTE: PolyBase is only available on SQL Server 19 and above, and only for Standard SQL Server.

The CData ODBC drivers offer unmatched performance for interacting with live Excel Online data using PolyBase due to optimized data processing built into the driver. When you issue complex SQL queries from SQL Server to Excel Online, the driver pushes down supported SQL operations, like filters and aggregations, directly to Excel Online and utilizes the embedded SQL engine to process unsupported operations (often SQL functions and JOIN operations) client-side. And with PolyBase, you can also join SQL Server data with Excel Online data, using a single query to pull data from distributed sources.

Connect to Excel Online

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs. To create an external data source in SQL Server using PolyBase, configure a System DSN (CData Excel Online Sys is created automatically).

You can connect to a workbook by providing authentication to Excel Online and then setting the following properties:

• Workbook: Set this to the name or Id of the workbook.

  If you want to view a list of information about the available workbooks, execute a query to the Workbooks view after you authenticate.

• UseSandbox: Set this to true if you are connecting to a workbook in a sandbox account. Otherwise, leave this blank to connect to a production account.

You use the OAuth authentication standard to authenticate to Excel Online. See the Getting Started section in the help documentation for a guide. Getting Started also guides you through executing SQL to worksheets and ranges.

Click "Test Connection" to ensure that the DSN is connected to Excel Online properly. Navigate to the Tables tab to review the table definitions for Excel Online.

Create an External Data Source for Excel Online Data

After configuring the connection, you need to create a master encryption key and a credential database for the external data source.

Creating a Master Encryption Key

Execute the following SQL command to create a new master key, 'ENCRYPTION,' to encrypt the credentials for the external data source.

CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'password';

Creating a Credential Database

Execute the following SQL command to create credentials for the external data source connected to Excel Online data.

NOTE: Since Excel Online does not require a User or Password to authenticate, you may use whatever values you wish for IDENTITY and SECRET.

CREATE DATABASE SCOPED CREDENTIAL excelonline_creds
WITH IDENTITY = 'username', SECRET = 'password';

Create an External Data Source for Excel Online

Execute a CREATE EXTERNAL DATA SOURCE SQL command to create an external data source for Excel Online with PolyBase:

• Set the LOCATION parameter , using the DSN and credentials configured earlier.

For Excel Online, set SERVERNAME to the URL or address for your server (e.g. 'localhost' or '127.0.0.1' for local servers; the remote URL for remote servers). Leave PORT empty. PUSHDOWN is set to ON by default, meaning the ODBC Driver can leverage server-side processing for complex queries.

CREATE EXTERNAL DATA SOURCE cdata_excelonline_source
WITH ( 
  LOCATION = 'odbc://SERVER_URL',
  CONNECTION_OPTIONS = 'DSN=CData Excel Online Sys',
  -- PUSHDOWN = ON | OFF,
  CREDENTIAL = excelonline_creds
);

Create External Tables for Excel Online

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to Excel Online data from your SQL Server instance. The table column definitions must match those exposed by the CData ODBC Driver for Excel Online. You can refer to the Tables tab of the DSN Configuration Wizard to see the table definition.

Sample CREATE TABLE Statement

The statement to create an external table based on a Excel Online Test_xlsx_Sheet1 would look similar to the following:

CREATE EXTERNAL TABLE Test_xlsx_Sheet1(
  Id [nvarchar](255) NULL,
  Column1 [nvarchar](255) NULL,
  ...
) WITH ( 
  LOCATION='Test_xlsx_Sheet1',
  DATA_SOURCE=cdata_excelonline_source
);

Having created external tables for Excel Online in your SQL Server instance, you are now able to query local and remote data simultaneously. Thanks to built-in query processing in the CData ODBC Driver, you know that as much query processing as possible is being pushed to Excel Online, freeing up local resources and computing power. Download a free, 30-day trial of the ODBC Driver for Excel Online and start working with live Excel Online data alongside your SQL Server data today.