How to connect PolyBase to SAS Data Sets

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 SAS Data Sets, you get access to your SAS Data Sets data directly alongside your SQL Server data. This article describes creating an external data source and external tables to grant access to live SAS Data Sets 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 SAS Data Sets data using PolyBase due to optimized data processing built into the driver. When you issue complex SQL queries from SQL Server to SAS Data Sets, the driver pushes down supported SQL operations, like filters and aggregations, directly to SAS Data Sets 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 SAS Data Sets data, using a single query to pull data from distributed sources.

Connect to SAS Data Sets

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 SAS Data Sets Sys is created automatically).

Set the following connection properties to connect to your SAS DataSet files:

Connecting to Local Files

• Set the Connection Type to "Local." Local files support SELECT, INSERT, and DELETE commands.
• Set the URI to a folder containing SAS files, e.g. C:\PATH\TO\FOLDER\.

Connecting to Cloud-Hosted SAS DataSet Files

While the driver is capable of pulling data from SAS DataSet files hosted on a variety of cloud data stores, INSERT, UPDATE, and DELETE are not supported outside of local files in this driver.

Set the Connection Type to the service hosting your SAS DataSet files. A unique prefix at the beginning of the URI connection property is used to identify the cloud data store and the remainder of the path is a relative path to the desired folder (one table per file) or single file (a single table). For more information, refer to the Getting Started section of the Help documentation.

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

Create an External Data Source for SAS Data Sets 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 SAS Data Sets data.

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

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

Create an External Data Source for SAS Data Sets

Execute a CREATE EXTERNAL DATA SOURCE SQL command to create an external data source for SAS Data Sets with PolyBase:

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

For SAS Data Sets, 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_sasdatasets_source
WITH ( 
  LOCATION = 'odbc://SERVER_URL',
  CONNECTION_OPTIONS = 'DSN=CData SAS Data Sets Sys',
  -- PUSHDOWN = ON | OFF,
  CREDENTIAL = sasdatasets_creds
);

Create External Tables for SAS Data Sets

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to SAS Data Sets data from your SQL Server instance. The table column definitions must match those exposed by the CData ODBC Driver for SAS Data Sets. 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 SAS Data Sets restaurants would look similar to the following:

CREATE EXTERNAL TABLE restaurants(
  name [nvarchar](255) NULL,
  borough [nvarchar](255) NULL,
  ...
) WITH ( 
  LOCATION='restaurants',
  DATA_SOURCE=cdata_sasdatasets_source
);

Having created external tables for SAS Data Sets 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 SAS Data Sets, freeing up local resources and computing power. Download a free, 30-day trial of the ODBC Driver for SAS Data Sets and start working with live SAS Data Sets data alongside your SQL Server data today.