Configure PolyBase to access external data in Teradata

Applies to: SQL Server

This article explains how to use PolyBase on a SQL Server instance to query external data in Teradata.

Prerequisites

If you haven't installed PolyBase, see PolyBase installation. The installation article explains the prerequisites.

Before creating a database scoped credential a Master Key must be created.

To use PolyBase on Teradata, VC++ redistributable is needed.

Configure a Teradata external data source

To query the data from a Teradata data source, you must create external tables to reference the external data. This section provides sample code to create these external tables.

The following Transact-SQL commands are used in this section:

• CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)
• CREATE EXTERNAL DATA SOURCE (Transact-SQL)
• CREATE EXTERNAL TABLE (Transact-SQL)
• CREATE STATISTICS (Transact-SQL)

1. Create a database scoped credential for accessing the Teradata source.

   /*  specify credentials to external data source
   *  IDENTITY: user name for external source. 
   *  SECRET: password for external source.
   */
   CREATE DATABASE SCOPED CREDENTIAL credential_name WITH IDENTITY = 'username', Secret = 'password';
   

   Important

   The Teradata ODBC Connector for PolyBase supports only basic authentication, not Kerberos authentication.

2. Create an external data source with CREATE EXTERNAL DATA SOURCE.

   /*  LOCATION: Location string should be of format '<vendor>://<server>[:<port>]'.
   * PUSHDOWN: specify whether computation should be pushed down to the source. ON by default.
   * CONNECTION_OPTIONS: Specify driver location
   * CREDENTIAL: the database scoped credential, created above.
   */  
   CREATE EXTERNAL DATA SOURCE external_data_source_name
   WITH (LOCATION = teradata://<server address>[:<port>],
   -- PUSHDOWN = ON | OFF,
   CREDENTIAL = credential_name);
   

3. Create an external table with CREATE EXTERNAL TABLE.

   /*
   * LOCATION: Two-part identifier indicating the database and the table name.
   * DATA_SOURCE: Data source created above.
   */
   CREATE EXTERNAL TABLE [TableC] (
     [MyKey] INT NOT NULL,
     [RandomInt] INT NOT NULL,
     [RandomFloat] DECIMAL(13, 2) NOT NULL)
   WITH (
     LOCATION = 'TD_SERVER_DB.TableC',
     DATA_SOURCE = external_data_source_name)
   

4. Optional: Create statistics on an external table.

   We recommend creating statistics on external table columns, especially the ones used for joins, filters and aggregates, for optimal query performance.

   CREATE STATISTICS statistics_name ON customer (C_CUSTKEY) WITH FULLSCAN; 
   

Important

Once you have created an external data source, you can use the CREATE EXTERNAL TABLE command to create a queryable table over that source.

Next steps

For more tutorials on creating external data sources and external tables to a variety of data sources, see PolyBase Transact-SQL reference.

To learn more about PolyBase, see Overview of SQL Server PolyBase.