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

Configure IBM Cloud Object Storage Connectivity for PolyBase

Connectivity to IBM Cloud Object Storage from PolyBase is made possible through CData Connect AI. To work with IBM Cloud Object Storage data from PolyBase, we start by creating and configuring a IBM Cloud Object Storage connection.

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

2. Select "IBM Cloud Object Storage" from the Add Connection panel

3. Enter the necessary authentication properties to connect to IBM Cloud Object Storage.

   Register a New Instance of Cloud Object Storage

   If you do not already have Cloud Object Storage in your IBM Cloud account, follow the procedure below to install an instance of SQL Query in your account:

   1. Log in to your IBM Cloud account.
   2. Navigate to the page, choose a name for your instance and click Create. You will be redirected to the instance of Cloud Object Storage you just created.

   Connecting using OAuth Authentication

   There are certain connection properties you need to set before you can connect. You can obtain these as follows:

   API Key

   To connect with IBM Cloud Object Storage, you need an API Key. You can obtain this as follows:

   1. Log in to your IBM Cloud account.
   2. Navigate to the Platform API Keys page.
   3. On the middle-right corner click "Create an IBM Cloud API Key" to create a new API Key.
   4. In the pop-up window, specify the API Key name and click "Create". Note the API Key as you can never access it again from the dashboard.

   Cloud Object Storage CRN

   If you have multiple accounts, specify the CloudObjectStorageCRN explicitly. To find the appropriate value, you can:

   • Query the Services view. This will list your IBM Cloud Object Storage instances along with the CRN for each.
   • Locate the CRN directly in IBM Cloud. To do so, navigate to your IBM Cloud Dashboard. In the Resource List, Under Storage, select your Cloud Object Storage resource to get its CRN.

   Connecting to Data

   You can now set the following to connect to data:

   • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
   • ApiKey: Set this to your API key which was noted during setup.
   • CloudObjectStorageCRN (Optional): Set this to the cloud object storage CRN you want to work with. While the connector attempts to retrieve this automatically, specifying this explicitly is recommended if you have more than Cloud Object Storage account.

   When you connect, the connector completes the OAuth process.

   1. Extracts the access token and authenticates requests.
   2. Saves OAuth values in OAuthSettingsLocation to be persisted across connections.
   
4. Click Save & Test
5. Navigate to the Permissions tab in the Add IBM Cloud Object Storage Connection page and update the User-based 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.
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 IBM Cloud Object Storage data from Polybase.

Create an External Data Source for IBM Cloud Object Storage 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 IBM Cloud Object Storage 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 IBM Cloud Object Storage

Execute a CREATE EXTERNAL DATA SOURCE SQL command to create an external data source for IBM Cloud Object Storage with PolyBase:

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

Create External Tables for IBM Cloud Object Storage

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to IBM Cloud Object Storage 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.

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 IBM Cloud Object Storage Objects would look similar to the following.

CREATE EXTERNAL TABLE Objects(
  Key COLLATE [nvarchar](255) NULL,
  Etag COLLATE [nvarchar](255) NULL,
  ...
) WITH ( 
  LOCATION='IBMCloudObjectStorage1.IBMCloudObjectStorage.Objects',
  DATA_SOURCE=ConnectCloudInstance
);

Having created external tables for IBM Cloud Object Storage 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!