Connect to DB2 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 DB2, you get access to your DB2 data directly alongside your SQL Server data. This article describes creating an external data source and external tables to grant access to live DB2 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 DB2, allowing you to query data from DB2 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 DB2, leveraging server-side processing to return the requested DB2 data quickly.

Configure DB2 Connectivity for PolyBase

Connectivity to DB2 from PolyBase is made possible through CData Connect AI. To work with DB2 data from PolyBase, we start by creating and configuring a DB2 connection.

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

2. Select "DB2" from the Add Connection panel

3. Enter the necessary authentication properties to connect to DB2.

   Set the following properties to connect to DB2:

   • Server: Set this to the name of the server running DB2.
   • Port: Set this to the port the DB2 server is listening on.
   • Database: Set this to the name of the DB2 database.
   • User: Set this to the username of a user allowed to access the database.
   • Password: Set this to the password of a user allowed to access the database.

   You will also need to install the corresponding DB2 driver:

   • Windows: Install the IBM Data Server Provider for .NET.

     On Windows, installing the IBM Data Server Provider is sufficient, as the installation registers it in the machine.config.

   • Java: Install the IBM Data Server Driver for JDBC.

     In the Java version, place the IBM Data Server Driver JAR in the www\WEB-INF\lib\ folder for this application.

   
4. Click Save & Test
5. Navigate to the Permissions tab in the Add DB2 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 DB2 data from Polybase.

Create an External Data Source for DB2 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 DB2 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 DB2

Execute a CREATE EXTERNAL DATA SOURCE SQL command to create an external data source for DB2 with PolyBase:

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

Create External Tables for DB2

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to DB2 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 DB2 Orders would look similar to the following.

CREATE EXTERNAL TABLE Orders(
  OrderName COLLATE [nvarchar](255) NULL,
  Freight COLLATE [nvarchar](255) NULL,
  ...
) WITH ( 
  LOCATION='DB21.DB2.Orders',
  DATA_SOURCE=ConnectCloudInstance
);

Having created external tables for DB2 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!