---
title: "Access external data: ODBC generic types - PolyBase"
description: PolyBase in SQL Server allows you to connect to compatible data sources through the ODBC connector. Install the ODBC driver and create external tables.
ms.date: 07/16/2020
ms.custom: seo-lt-2019
ms.prod: sql
ms.technology: polybase
ms.topic: conceptual
author: MikeRayMSFT
ms.author: mikeray
ms.reviewer: mikeray
monikerRange: ">= sql-server-linux-ver15 || >= sql-server-ver15"
---
# Configure PolyBase to access external data with ODBC generic types

 [!INCLUDE [SQL Server](../../includes/applies-to-version/sqlserver.md)]

PolyBase in SQL Server 2019 allows you to connect to ODBC -compatible data sources using the ODBC connector.

This article demonstrate how to create configuring connectivity using an ODBC data source. The guidance provided uses one specific ODBC driver as an example. Check with your ODBC provider for specific examples. Reference the ODBC driver documentation for your data source to determine the appropriate connection string options. The examples in this article may not apply to any specific ODBC driver.

## Prerequisites

>[!NOTE]
>This feature requires SQL Server on Windows.

* PolyBase must be installed and enabled for your SQL Server instance [PolyBase installation](polybase-installation.md).

* Before creating a database scoped credential, a [Master Key](../../t-sql/statements/create-master-key-transact-sql.md) must be created.

## Install the ODBC driver

Download and install the ODBC driver of the data source you want to connect to on each of the PolyBase nodes. Once the driver is properly installed, you can view and test the driver from the **ODBC Data Source Administrator**.

![PolyBase scale-out groups](../../relational-databases/polybase/media/polybase-odbc-admin.png) 

In the example above, the name of the driver is circled in red. Use this name when you create the external data source.

> [!IMPORTANT]
> In order to improve query performance, enable connection pooling. This can be accomplished from the **ODBC Data Source Administrator**.

## Create dependent objects in SQL Server

To use the ODBC data source a few objects must first be created to complete the configuration.

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

* [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)](../../t-sql/statements/create-database-scoped-credential-transact-sql.md)
* [CREATE EXTERNAL DATA SOURCE (Transact-SQL)](../../t-sql/statements/create-external-data-source-transact-sql.md) 

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

    ```sql
    CREATE DATABASE SCOPED CREDENTIAL <credential_name> WITH IDENTITY = '<username>', Secret = '<password>';
    ```

    For example, the following example creates a credential named `credential_name`, with an identity of `username` and a complex password.

    ```sql
    CREATE DATABASE SCOPED CREDENTIAL credential_name WITH IDENTITY = 'username', Secret = 'BycA4ZjrE#*2W%!';
    ```

1. Create an external data source with [CREATE EXTERNAL DATA SOURCE](../../t-sql/statements/create-external-data-source-transact-sql.md).

    ```sql
    CREATE EXTERNAL DATA SOURCE <external_data_source_name>
    WITH ( LOCATION = 'odbc://<ODBC server address>[:<port>]',
    CONNECTION_OPTIONS = 'Driver={<Name of Installed Driver>};
    ServerNode = <name of server  address>:<Port>',
    -- PUSHDOWN = [ON] | OFF,
    CREDENTIAL = <credential_name> );
    ```

    The following example creates an external data source:
    * Named `external_data_source_name`
    * Located at the ODBC `SERVERNAME` and port `4444`
    * Connecting with `CData ODBC Driver For SAP 2015` - This is the driver created under [Install the ODBC driver](#install-the-odbc-driver)
    * On `ServerNode` `sap_server_node` port `5555`
    * Configured for processing pushed down to the server (`PUSHDOWN = ON`)
    * Using the `credential_name` credential

    ```sql
    CREATE EXTERNAL DATA SOURCE external_data_source_name
    WITH ( LOCATION = 'odbc://SERVERNAME:4444',
    CONNECTION_OPTIONS = 'Driver={CData ODBC Driver For SAP 2015};
    ServerNode = sap_server_node:5555',
    PUSHDOWN = ON,
    CREDENTIAL = credential_name );
    ```
    
## Create an external table

Once you have created the dependent objects you can create an external tables using T-SQL. 

The following Transact-SQL commands are used in this section:
* [CREATE EXTERNAL TABLE](../../t-sql/statements/create-external-table-transact-sql.md)
* [CREATE STATISTICS (Transact-SQL)](../../t-sql/statements/create-statistics-transact-sql.md)

1. Create one or more external tables.

   Create an external table. You will need to reference the external data source created above using the `DATA_SOURCE` argument and specify the source table as the `LOCATION`. You do not need to reference all columns but you will need to ensure that the types are correctly mapped.  

   ```sql
     CREATE EXTERNAL TABLE <your_table_name>
     (
     <col1_name>     DECIMAL(38) NOT NULL,
     <col2_name>     DECIMAL(38) NOT NULL,
     <col3_name>     CHAR COLLATE Latin1_General_BIN NOT NULL
     )
     WITH (
     LOCATION='<sap_table_name>',
     DATA_SOURCE= <external_data_source_name>
     )
     ;
   ```

   > [!NOTE]
   > Note you can re-use the dependent objects for all external tables using this external data source.

1. **Optional:** Create statistics on an external table.

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

    ```sql
    CREATE STATISTICS statistics_name ON contact (FirstName) WITH FULLSCAN; 
    ```
    
## Next steps

To learn more about PolyBase, see [Overview of SQL Server PolyBase](polybase-guide.md).