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URL: https://www.cdata.com/kb/tech/odata-cloud-polybase.rst

⇱ Connect to OData Services as an External Data Source using PolyBase

Connect to OData Services as an External Data Source using PolyBase

👁 Dibyendu Datta
Dibyendu Datta
Lead Technology Evangelist
Use CData Connect AI and PolyBase to create an external data source in SQL Swerver with access to live OData services.

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 OData, you get access to your OData services directly alongside your SQL Server data. This article describes creating an external data source and external tables to grant access to live OData services 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 OData, allowing you to query data from OData 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 OData, leveraging server-side processing to return the requested OData services quickly.

About OData Data Integration

CData simplifies access and integration of live OData services data. Our customers leverage CData connectivity to:

  • Access OData versions 2.0, 3.0, and 4.0, working with legacy services and the latest features and capabilities.
  • Leverage advanced query options, including $filter, $select, and $expand, enhancing data retrieval from 3rd party tools.
  • Use Server-side execution of aggregation and grouping to minimize data transfer and boost performance.
  • Authenticate securely using a variety of schemes, including Azure AD, digest, negotiate, NTLM, OAuth, and more means secure authentication with every connection.
  • Use SQL stored procedures to manage OData service entities - listing, creating, and removing associations between entities.

Customers use CData's solutions to regularly integrate their OData services with preferred tools, such as Power BI, MicroStrategy, or Tableau, and to replicate data from OData services to their databases or data warehouses.


Getting Started


Configure OData Connectivity for PolyBase

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

  1. Log into Connect AI, click Sources, and then click Add Connection
    2. 👁 Adding a Connection
  2. Select "OData" from the Add Connection panel
    3. 👁 Selecting a data source
  3. Enter the necessary authentication properties to connect to OData.

    The User and Password properties, under the Authentication section, must be set to valid OData user credentials. In addition, specify a URL to a valid OData server organization root or OData services file.

    👁 Configuring a connection (Salesforce is shown)
  4. Click Save & Test
  5. Navigate to the Permissions tab in the Add OData 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 OData services from Polybase.

Create an External Data Source for OData Services

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 OData services.

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 OData

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

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

Create External Tables for OData

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to OData services 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 OData Orders would look similar to the following.

CREATE EXTERNAL TABLE Orders(
 OrderName COLLATE [nvarchar](255) NULL,
 Freight COLLATE [nvarchar](255) NULL,
 ...
) WITH ( 
 LOCATION='OData1.OData.Orders',
 DATA_SOURCE=ConnectCloudInstance
);

Having created external tables for OData 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!