Connect to Azure Analysis Services Data as an External Data Source using PolyBase

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 Azure Analysis Services, you get access to your Azure Analysis Services data directly alongside your SQL Server data. This article describes creating an external data source and external tables to grant access to live Azure Analysis Services data using T-SQL queries.

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

CData Connect AI provides a pure SQL Server interface for Azure Analysis Services, allowing you to query data from Azure Analysis Services without replicating the data to a natively supported database. Using optimized data processing out of the box, CData Connect AI pushes all supported SQL operations (filters, JOINs, etc.) directly to Azure Analysis Services, leveraging server-side processing to return the requested Azure Analysis Services data quickly.

Configure Azure Analysis Services Connectivity for PolyBase

Connectivity to Azure Analysis Services from PolyBase is made possible through CData Connect AI. To work with Azure Analysis Services data from PolyBase, we start by creating and configuring a Azure Analysis Services connection.

1. Log into Connect AI, click Sources, and then click Add Connection
👁 Adding a Connection

2. Select "Azure Analysis Services" from the Add Connection panel
👁 Selecting a data source

3. Enter the necessary authentication properties to connect to Azure Analysis Services.

   To connect to Azure Analysis Services, set the Url property to a valid server, for instance, asazure://southcentralus.asazure.windows.net/server, in addition to authenticating. Optionally, set Database to distinguish which Azure database on the server to connect to.

   Azure Analysis Services uses the OAuth authentication standard. OAuth requires the authenticating user to interact with Azure Analysis Services using the browser. You can connect without setting any connection properties for your user credentials. See the Help documentation for more information.

   👁 Configuring a connection (Salesforce is shown)
   
4. Click Save & Test
5. Navigate to the Permissions tab in the Add Azure Analysis Services Connection page and update the User-based permissions. 👁 Updating permissions
   

Add a Personal Access Token

When connecting to Connect AI through the REST API, the OData API, or the Virtual SQL Server, a Personal Access Token (PAT) is used to authenticate the connection to Connect AI. It is best practice to create a separate PAT for each service to maintain granularity of access.

1. Click on the Gear icon () at the top right of the Connect AI app to open the settings page.
2. On the Settings page, go to the Access Tokens section and click Create PAT.
3. Give the PAT a name and click Create. 👁 Creating a new PAT
   
4. The personal access token is only visible at creation, so be sure to copy it and store it securely for future use.

With the connection configured and a PAT generated, you are ready to connect to Azure Analysis Services data from Polybase.

Create an External Data Source for Azure Analysis Services Data

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

Creating a Credential Database

Execute the following SQL command to create credentials for the external data source connected to Azure Analysis Services data.

NOTE: Set IDENTITY to your Connect AI username and set SECRET to your Personal Access Token.

CREATE DATABASE SCOPED CREDENTIAL ConnectCloudCredentials
WITH IDENTITY = 'yourusername', SECRET = 'yourPAT';

Create an External Data Source for Azure Analysis Services

Execute a CREATE EXTERNAL DATA SOURCE SQL command to create an external data source for Azure Analysis Services with PolyBase:

CREATE EXTERNAL DATA SOURCE ConnectCloudInstance
WITH ( 
 LOCATION = 'sqlserver://tds.cdata.com:14333',
 PUSHDOWN = ON,
 CREDENTIAL = ConnectCloudCredentials
);

Create External Tables for Azure Analysis Services

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to Azure Analysis Services data from your SQL Server instance. The table column definitions must match those exposed by CData Connect AI. You can use the Data Explorer in Connect AI to see the table definition.

👁 Table definition in the Data Explorer (Salesforce is shown)

Sample CREATE TABLE Statement

Execute a CREATE EXTERNAL TABLE SQL command to create the external table(s), using the collation and setting the LOCATION to three-part notation for the connection, catalog, and table. The statement to create an external table based on a Azure Analysis Services Customer would look similar to the following.

CREATE EXTERNAL TABLE Customer(
 Country COLLATE [nvarchar](255) NULL,
 Education COLLATE [nvarchar](255) NULL,
 ...
) WITH ( 
 LOCATION='AAS1.AAS.Customer',
 DATA_SOURCE=ConnectCloudInstance
);

Having created external tables for Azure Analysis Services in your SQL Server instance, you are now able to query local and remote data simultaneously. To get live data access to hundreds of SaaS, Big Data, and NoSQL sources directly from your SQL Server database, try CData Connect AI today!