Configure PolyBase to access external data in Teradata

APPLIES TO: yesSQL Server noAzure SQL Database noAzure SQL Data Warehouse noParallel Data Warehouse

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:

  1. Create a database scoped credential for accessing the MongoDB 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';
    
  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. 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

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