---
description: "CREATE EXTERNAL DATA SOURCE (Transact-SQL)"
title: "CREATE EXTERNAL DATA SOURCE (Transact-SQL) | Microsoft Docs"
ms.custom: ""
ms.date: 02/26/2020
ms.prod: sql
ms.prod_service: "database-engine, sql-database, sql-data-warehouse, pdw"
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  - "CREATE EXTERNAL DATA SOURCE"
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helpviewer_keywords: 
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  - "External, data source"
  - "PolyBase, create data source"
author: markingmyname
ms.author: maghan
monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-server-2016||=sqlallproducts-allversions||>=sql-server-linux-2017||=azuresqldb-mi-current"
---

# CREATE EXTERNAL DATA SOURCE (Transact-SQL)

Creates an external data source for querying using SQL Server, SQL Database, Azure Synapse Analytics, or Analytics Platform System (Parallel Data Warehouse or PDW).

This article provides the syntax, arguments, remarks, permissions, and examples for whichever SQL product you choose.

For more information about the syntax conventions, see [Transact-SQL Syntax Conventions](../../t-sql/language-elements/transact-sql-syntax-conventions-transact-sql.md).

[!INCLUDE[select-product](../../includes/select-product.md)]

::: moniker range=">=sql-server-2016||>=sql-server-linux-2017||=sqlallproducts-allversions"

:::row:::
    :::column:::
        **_\* SQL Server \*_**  
    :::column-end:::
    :::column:::
        [SQL Database](create-external-data-source-transact-sql.md?view=azuresqldb-current)
    :::column-end:::
    :::column:::
        [Azure Synapse<br />Analytics](create-external-data-source-transact-sql.md?view=azure-sqldw-latest)
    :::column-end:::
    :::column:::
        [Analytics Platform<br />System (PDW)](create-external-data-source-transact-sql.md?view=aps-pdw-2016-au7)
    :::column-end:::
:::row-end:::

&nbsp;

## Overview: SQL Server

Creates an external data source for PolyBase queries. External data sources are used to establish connectivity and support these primary use cases:

- Data virtualization and data load using [PolyBase][intro_pb]
- Bulk load operations using `BULK INSERT` or `OPENROWSET`

**Applies to**: Starting with [!INCLUDE[ssSQL15](../../includes/sssql15-md.md)]

## Syntax

```syntaxsql
CREATE EXTERNAL DATA SOURCE <data_source_name>
WITH
  ( [ LOCATION = '<prefix>://<path>[:<port>]' ]
    [ [ , ] CONNECTION_OPTIONS = '<name_value_pairs>']
    [ [ , ] CREDENTIAL = <credential_name> ]
    [ [ , ] PUSHDOWN = { ON | OFF } ]
    [ [ , ] TYPE = { HADOOP | BLOB_STORAGE } ]
    [ [ , ] RESOURCE_MANAGER_LOCATION = '<resource_manager>[:<port>]' )
[ ; ]
```

## Arguments

### data_source_name

Specifies the user-defined name for the data source. The name must be unique within the database in [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)].

### LOCATION = *`'<prefix>://<path[:port]>'`*

Provides the connectivity protocol and path to the external data source.

| External Data Source    | Location prefix | Location path                                         | Supported locations by product / service |
| ----------------------- | --------------- | ----------------------------------------------------- | ---------------------------------------- |
| Cloudera or Hortonworks | `hdfs`          | `<Namenode>[:port]`                                   | Starting with [!INCLUDE[ssSQL15](../../includes/sssql15-md.md)]                       |
| Azure Storage account(V2) | `wasb[s]`       | `<container>@<storage_account>.blob.core.windows.net` | Starting with [!INCLUDE[ssSQL15](../../includes/sssql15-md.md)]         Hierarchical Namespace **not** supported |
| [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]              | `sqlserver`     | `<server_name>[\<instance_name>][:port]`              | Starting with [!INCLUDE[sql-server-2019](../../includes/sssqlv15-md.md)]                       |
| Oracle                  | `oracle`        | `<server_name>[:port]`                                | Starting with [!INCLUDE[sql-server-2019](../../includes/sssqlv15-md.md)]                       |
| Teradata                | `teradata`      | `<server_name>[:port]`                                | Starting with [!INCLUDE[sql-server-2019](../../includes/sssqlv15-md.md)]                       |
| MongoDB or CosmosDB     | `mongodb`       | `<server_name>[:port]`                                | Starting with [!INCLUDE[sql-server-2019](../../includes/sssqlv15-md.md)]                       |
| ODBC                    | `odbc`          | `<server_name>[:port]`                                | Starting with [!INCLUDE[sql-server-2019](../../includes/sssqlv15-md.md)] - Windows only        |
| Bulk Operations         | `https`         | `<storage_account>.blob.core.windows.net/<container>` | Starting with [!INCLUDE[ssSQL17](../../includes/sssql17-md.md)]                        |
| Edge Hub         | `edgehub`         | Not Applicable | EdgeHub is always local to the instance of [Azure SQL Edge](/azure/azure-sql-edge/overview/). As such there is no need to specify a path or port value. Only available in Azure SQL Edge.                      |
| Kafka        | `kafka`         | `<Kafka IP Address>[:port]` | Only available in Azure SQL Edge.                      |

Location path:

- `<`Namenode`>` = the machine name, name service URI, or IP address of the `Namenode` in the Hadoop cluster. PolyBase must resolve any DNS names used by the Hadoop cluster. <!-- For highly available Hadoop configurations, provide the Nameservice ID as the `LOCATION`. -->
- `port` = The port that the external data source is listening on. In Hadoop, the port can be found using the `fs.defaultFS` configuration parameter. The default is 8020.
- `<container>` = the container of the storage account holding the data. Root containers are read-only, data can't be written back to the container.
- `<storage_account>` = the storage account name of the azure resource.
- `<server_name>` = the host name.
- `<instance_name>` = the name of the SQL Server named instance. Used if you have SQL Server Browser Service running on the target instance.

Additional notes and guidance when setting the location:

- The [!INCLUDE[ssDEnoversion](../../includes/ssdenoversion-md.md)] doesn't verify the existence of the external data source when the object is created. To validate, create an external table using the external data source.
- Use the same external data source for all tables when querying Hadoop to ensure consistent querying semantics.
- You can use the `sqlserver` location prefix to connect [!INCLUDE[sql-server-2019](../../includes/sssqlv15-md.md)] to another [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)], to [!INCLUDE[ssSDSfull](../../includes/sssdsfull-md.md)], or to Azure Synapse Analytics.
- Specify the `Driver={<Name of Driver>}` when connecting via `ODBC`.
- `wasbs` is optional but recommended for accessing Azure Storage Accounts as data will be sent using a secure TLS/SSL connection.
- `abfs` or `abfss` APIs are not supported when accessing Azure Storage Accounts.
- The Hierarchical Namespace option for Azure Storage Accounts(V2) is not supported. Please ensure that this option remains **disabled**.
- To ensure successful PolyBase queries during a Hadoop `Namenode` fail-over, consider using a virtual IP address for the `Namenode` of the Hadoop cluster. If you don't, execute an [ALTER EXTERNAL DATA SOURCE][alter_eds] command to point to the new location.

### CONNECTION_OPTIONS = *key_value_pair*

Specifies additional options when connecting over `ODBC` to an external data source.

The name of the driver is required as a minimum, but there are other options such as `APP='<your_application_name>'` or `ApplicationIntent= ReadOnly|ReadWrite` that are also useful to set and can assist with troubleshooting.

Refer to the `ODBC` product documentation for a list of permitted [CONNECTION_OPTIONS][connection_options]

### PUSHDOWN = *ON | OFF*

States whether computation can be pushed down to the external data source. It is on by default.

`PUSHDOWN` is supported when connecting to SQL Server, Oracle, Teradata, MongoDB, or ODBC at the external data source level.

Enabling or disabling push-down at the query level is achieved through a [hint][hint_pb].

### CREDENTIAL = *credential_name*

Specifies a database-scoped credential for authenticating to the external data source.

Additional notes and guidance when creating a credential:

- `CREDENTIAL` is only required if the data has been secured. `CREDENTIAL` isn't required for data sets that allow anonymous access.
- When `TYPE` = `BLOB_STORAGE` the credential must be created using `SHARED ACCESS SIGNATURE` as the identity. Furthermore, the SAS token should be configured as follows:
  - Exclude the leading `?` when configured as the secret
  - Have at least read permission on the file that should be loaded (for example `srt=o&sp=r`)
  - Use a valid expiration period (all dates are in UTC time).

For an example of using a `CREDENTIAL` with `SHARED ACCESS SIGNATURE` and `TYPE` = `BLOB_STORAGE`, see [Create an external data source to execute bulk operations and retrieve data from Azure Storage into SQL Database](#i-create-an-external-data-source-for-bulk-operations-retrieving-data-from-azure-storage)

To create a database scoped credential, see [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)][create_dsc].

### TYPE = *[ HADOOP | BLOB_STORAGE ]*

Specifies the type of the external data source being configured. This parameter isn't always required.

- Use HADOOP when the external data source is Cloudera, Hortonworks, or an Azure Storage account.
- Use BLOB_STORAGE when executing bulk operations from Azure Storage account using [BULK INSERT][bulk_insert], or [OPENROWSET][openrowset] with [!INCLUDE[ssSQLv14_md](../../includes/sssqlv14-md.md)].

> [!IMPORTANT]
> Do not set `TYPE` if using any other external data source.

For an example of using `TYPE` = `HADOOP` to load data from an Azure Storage account, see [Create external data source to access data in Azure Storage using the wasb:// interface](#e-create-external-data-source-to-access-data-in-azure-storage-using-the-wasb-interface) <!--[Create external data source to reference Azure Storage](#e-create-external-data-source-to-reference-azure-storage).-->

### RESOURCE_MANAGER_LOCATION = *'ResourceManager_URI[:port]'*

Configure this optional value when connecting to Hortonworks or Cloudera.

When the `RESOURCE_MANAGER_LOCATION` is defined, the Query Optimizer will make a cost-based decision to improve performance. A MapReduce job can be used to push down the computation to Hadoop. Specifying the `RESOURCE_MANAGER_LOCATION` can significantly reduce the volume of data transferred between Hadoop and [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)], which can lead to improved query performance.

If the Resource Manager isn't specified, pushing compute to Hadoop is disabled for PolyBase queries.

If the port isn't specified, the default value is chosen using the current setting for 'hadoop connectivity' configuration.

| Hadoop Connectivity | Default Resource Manager Port |
| ------------------- | ----------------------------- |
| 1                   | 50300                         |
| 2                   | 50300                         |
| 3                   | 8021                          |
| 4                   | 8032                          |
| 5                   | 8050                          |
| 6                   | 8032                          |
| 7                   | 8050                          |

For a complete list of supported Hadoop versions, see [PolyBase Connectivity Configuration (Transact-SQL)][connectivity_pb].

> [!IMPORTANT]  
> The RESOURCE_MANAGER_LOCATION value is not validated when you create the external data source. Entering an incorrect value may cause query failure at execution time whenever push-down is attempted as the provided value would not be able to resolve.

[Create external data source to reference Hadoop with push-down enabled](#c-create-external-data-source-to-reference-hadoop-with-push-down-enabled) provides a concrete example and further guidance.

## Permissions

Requires `CONTROL` permission on database in [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)].

## Locking

Takes a shared lock on the `EXTERNAL DATA SOURCE` object.

## Security

PolyBase supports proxy based authentication for most external data sources. Create a database scoped credential to create the proxy account.

When you connect to the storage or data pool in a SQL Server big data cluster, the user's credentials are passed through to the back-end system. Create logins in the data pool itself to enable pass through authentication.

Currently a SAS token with type `HADOOP` is unsupported. It's only supported with a storage account access key. Attempting to create an external data source with type `HADOOP` and a SAS credential fails with the following error:

`Msg 105019, Level 16, State 1 - EXTERNAL TABLE access failed due to internal error: 'Java exception raised on call to HdfsBridge_Connect. Java exception message: Parameters provided to connect to the Azure storage account are not valid.: Error [Parameters provided to connect to the Azure storage account are not valid.] occurred while accessing external file.'`

## Examples (Starting with [!INCLUDE[ssSQL15](../../includes/sssql15-md.md)])

> [!IMPORTANT]
> For information on how to install and enable PolyBase, see [Install PolyBase on Windows](../../relational-databases/polybase/polybase-installation.md)

### A. Create external data source in SQL Server 2019 to reference Oracle

To create an external data source that references Oracle, ensure you have a database scoped credential. You may optionally also enable or disable push-down of computation against this data source.

```sql
-- Create a database master key if one does not already exist, using your own password. This key is used to encrypt the credential secret in next step.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '!MyC0mpl3xP@ssw0rd!' ;

-- Create a database scoped credential with Azure storage account key as the secret.
CREATE DATABASE SCOPED CREDENTIAL OracleProxyAccount
WITH
     IDENTITY = 'oracle_username',
     SECRET = 'oracle_password' ;

CREATE EXTERNAL DATA SOURCE MyOracleServer
WITH
  ( LOCATION = 'oracle://145.145.145.145:1521',
    CREDENTIAL = OracleProxyAccount,
    PUSHDOWN = ON
  ) ;
```

For additional examples to other data sources such as MongoDB, see [Configure PolyBase to access external data in MongoDB][mongodb_pb]

### B. Create external data source to reference Hadoop

To create an external data source to reference your Hortonworks or Cloudera Hadoop cluster, specify the machine name, or IP address of the Hadoop `Namenode` and port. <!-- Provide the Nameservice ID as the `LOCATION` for highly available configurations. -->

```sql
CREATE EXTERNAL DATA SOURCE MyHadoopCluster
WITH
  ( LOCATION = 'hdfs://10.10.10.10:8050' ,
    TYPE = HADOOP
  ) ;
```

### C. Create external data source to reference Hadoop with push-down enabled

Specify the `RESOURCE_MANAGER_LOCATION` option to enable push-down computation to Hadoop for PolyBase queries. Once enabled, PolyBase makes a cost-based decision to determine whether the query computation should be pushed to Hadoop.

```sql
CREATE EXTERNAL DATA SOURCE MyHadoopCluster
WITH
  ( LOCATION = 'hdfs://10.10.10.10:8020' ,
    TYPE = HADOOP ,
    RESOURCE_MANAGER_LOCATION = '10.10.10.10:8050'
  ) ;
```

### D. Create external data source to reference Kerberos-secured Hadoop

To verify if the Hadoop cluster is Kerberos-secured, check the value of hadoop.security.authentication property in Hadoop core-site.xml. To reference a Kerberos-secured Hadoop cluster, you must specify a database scoped credential that contains your Kerberos username and password. The database master key is used to encrypt the database scoped credential secret.

```sql
-- Create a database master key if one does not already exist, using your own password. This key is used to encrypt the credential secret in next step.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'S0me!nfo' ;

-- Create a database scoped credential with Kerberos user name and password.
CREATE DATABASE SCOPED CREDENTIAL HadoopUser1
WITH
     IDENTITY = '<hadoop_user_name>',
     SECRET = '<hadoop_password>' ;

-- Create an external data source with CREDENTIAL option.
CREATE EXTERNAL DATA SOURCE MyHadoopCluster
WITH
  ( LOCATION = 'hdfs://10.10.10.10:8050' ,
    CREDENTIAL = HadoopUser1 ,
    TYPE = HADOOP ,
    RESOURCE_MANAGER_LOCATION = '10.10.10.10:8050'
  );
```

### E. Create external data source to access data in Azure Storage using the wasb:// interface
In this example, the external data source is an Azure V2 Storage account named `logs`. The container is called `daily`. The Azure Storage external data source is for data transfer only. It doesn't support predicate push-down. Hierarchical namespaces are not supported when accessing data via the the `wasb://` interface.

This example shows how to create the database scoped credential for authentication to an Azure V2 Storage account. Specify the Azure Storage account key in the database credential secret. You can specify any string in database scoped credential identity as it isn't used during authentication to Azure Storage.

```sql
-- Create a database master key if one does not already exist, using your own password. This key is used to encrypt the credential secret in next step.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'S0me!nfo' ;

-- Create a database scoped credential with Azure storage account key as the secret.
CREATE DATABASE SCOPED CREDENTIAL AzureStorageCredential
WITH
  IDENTITY = '<my_account>' ,
  SECRET = '<azure_storage_account_key>' ;

-- Create an external data source with CREDENTIAL option.
CREATE EXTERNAL DATA SOURCE MyAzureStorage
WITH
  ( LOCATION = 'wasbs://daily@logs.blob.core.windows.net/' ,
    CREDENTIAL = AzureStorageCredential ,
    TYPE = HADOOP
  ) ;
```

### F. Create external data source to reference a SQL Server named instance via PolyBase connectivity ([!INCLUDE[sql-server-2019](../../includes/sssqlv15-md.md)])

To create an external data source that references a named instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)], you can use CONNECTION_OPTIONS to specify the instance name. In below example, `WINSQL2019` is the host name and `SQL2019` is the instance name.

```sql
CREATE EXTERNAL DATA SOURCE SQLServerInstance2
WITH (
  LOCATION = 'sqlserver://WINSQL2019' ,
  CONNECTION_OPTIONS = 'Server=%s\SQL2019' ,
  CREDENTIAL = SQLServerCredentials
) ;
```

Alternatively, you can use a port to connect to a [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] instance.

```sql
CREATE EXTERNAL DATA SOURCE SQLServerInstance2
WITH (
  LOCATION = 'sqlserver://WINSQL2019:58137' ,
  CREDENTIAL = SQLServerCredentials
) ;
```

### G. Create external data source to reference Kafka

In this example, the external data source is a Kafak server with IP address xxx.xxx.xxx.xxx and listenning on port 1900. The kafka external data source is only for data streaming and does not support predicate push down.

```sql
-- Create an External Data Source for Kafka
CREATE EXTERNAL DATA SOURCE MyKafkaServer WITH (
    LOCATION = 'kafka://xxx.xxx.xxx.xxx:1900'
)
go
```

### H. Create external data source to reference EdgeHub

In this example, the external data source is a EdgeHub running on the same edge device as Azure SQL Edge. The edgeHub external data source is only for data streaming and does not support predicate push down.

```sql
-- Create an External Data Source for Kafka
CREATE EXTERNAL DATA SOURCE MyEdgeHub WITH (
    LOCATION = 'edgehub://'
)
go
```

## Examples: Bulk Operations

> [!IMPORTANT]
> Do not add a trailing **/**, file name, or shared access signature parameters at the end of the `LOCATION` URL when configuring an external data source for bulk operations.

### I. Create an external data source for bulk operations retrieving data from Azure Storage

**Applies to:** [!INCLUDE[ssSQLv14_md](../../includes/sssqlv14-md.md)].
Use the following data source for bulk operations using [BULK INSERT][bulk_insert] or [OPENROWSET][openrowset]. The credential must set `SHARED ACCESS SIGNATURE` as the identity, mustn't have the leading `?` in the SAS token, must have at least read permission on the file that should be loaded (for example `srt=o&sp=r`), and the expiration period should be valid (all dates are in UTC time). For more information on shared access signatures, see [Using Shared Access Signatures (SAS)][sas_token].

```sql
CREATE DATABASE SCOPED CREDENTIAL AccessAzureInvoices
WITH
  IDENTITY = 'SHARED ACCESS SIGNATURE',
  -- Remove ? from the beginning of the SAS token
  SECRET = '******srt=sco&sp=rwac&se=2017-02-01T00:55:34Z&st=2016-12-29T16:55:34Z***************' ;

CREATE EXTERNAL DATA SOURCE MyAzureInvoices
WITH
  ( LOCATION = 'https://newinvoices.blob.core.windows.net/week3' ,
    CREDENTIAL = AccessAzureInvoices ,
    TYPE = BLOB_STORAGE
  ) ;
```

To see this example in use, see the [BULK INSERT][bulk_insert_example] example.

## See Also

- [ALTER EXTERNAL DATA SOURCE (Transact-SQL)][alter_eds]
- [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)][create_dsc]
- [CREATE EXTERNAL FILE FORMAT (Transact-SQL)][create_eff]
- [CREATE EXTERNAL TABLE (Transact-SQL)][create_etb]
- [sys.external_data_sources (Transact-SQL)][cat_eds]
- [Using Shared Access Signatures (SAS)][sas_token]

<!-- links to external pages -->
<!-- SQL Docs -->
[bulk_insert]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql
[bulk_insert_example]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql#f-importing-data-from-a-file-in-azure-storage
[openrowset]: https://docs.microsoft.com/sql/t-sql/functions/openrowset-transact-sql

[create_dsc]: https://docs.microsoft.com/sql/t-sql/statements/create-database-scoped-credential-transact-sql
[create_eff]: https://docs.microsoft.com/sql/t-sql/statements/create-external-file-format-transact-sql
[create_etb]: https://docs.microsoft.com/sql/t-sql/statements/create-external-table-transact-sql
[create_etb_as_sel]: https://docs.microsoft.com/sql/t-sql/statements/create-external-table-as-select-transact-sql?view=azure-sqldw-latest
[create_tbl_as_sel]: https://docs.microsoft.com/sql/t-sql/statements/create-table-as-select-azure-sql-data-warehouse?view=azure-sqldw-latest

[alter_eds]: https://docs.microsoft.com/sql/t-sql/statements/alter-external-data-source-transact-sql

[cat_eds]: https://docs.microsoft.com/sql/relational-databases/system-catalog-views/sys-external-data-sources-transact-sql
<!-- PolyBase docs -->
[intro_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-guide
[mongodb_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-configure-mongodb
[connectivity_pb]:https://docs.microsoft.com/sql/database-engine/configure-windows/polybase-connectivity-configuration-transact-sql
[connection_options]: https://docs.microsoft.com/sql/relational-databases/native-client/applications/using-connection-string-keywords-with-sql-server-native-client
[hint_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-pushdown-computation#force-pushdown

<!-- Azure Docs -->
[sas_token]: https://docs.microsoft.com/azure/storage/storage-dotnet-shared-access-signature-part-1

::: moniker-end
::: moniker range="=azuresqldb-current||=sqlallproducts-allversions"

:::row:::
    :::column:::
        [SQL Server](create-external-data-source-transact-sql.md?view=sql-server-2017)
    :::column-end:::
    :::column:::
        **_\* SQL Database \*_** &nbsp;
    :::column-end:::
    :::column:::
        [Azure Synapse<br />Analytics](create-external-data-source-transact-sql.md?view=azure-sqldw-latest)
    :::column-end:::
    :::column:::
        [Analytics Platform<br />System (PDW)](create-external-data-source-transact-sql.md?view=aps-pdw-2016-au7)
    :::column-end:::
:::row-end:::

&nbsp;

## Overview: Azure SQL Database

Creates an external data source for elastic queries. External data sources are used to establish connectivity and support these primary use cases:

- Bulk load operations using `BULK INSERT` or `OPENROWSET`
- Query remote SQL Database or Azure Synapse instances using SQL Database with [elastic query][remote_eq]
- Query a sharded Azure SQL Database using [elastic query][sharded_eq]

## Syntax

```syntaxsql
CREATE EXTERNAL DATA SOURCE <data_source_name>
WITH
  ( [ LOCATION = '<prefix>://<path>[:<port>]' ]
    [ [ , ] CREDENTIAL = <credential_name> ]
    [ [ , ] TYPE = { BLOB_STORAGE | RDBMS | SHARD_MAP_MANAGER } ]
    [ [ , ] DATABASE_NAME = '<database_name>' ]
    [ [ , ] SHARD_MAP_NAME = '<shard_map_manager>' ] )
[ ; ]
```

## Arguments

### data_source_name

Specifies the user-defined name for the data source. The name must be unique within the database in SQL Database.

### LOCATION = *`'<prefix>://<path[:port]>'`*

Provides the connectivity protocol and path to the external data source.

| External Data Source   | Location prefix | Location path                                         |
| ---------------------- | --------------- | ----------------------------------------------------- |
| Bulk Operations        | `https`         | `<storage_account>.blob.core.windows.net/<container>` |
| Elastic Query (shard)  | Not required    | `<shard_map_server_name>.database.windows.net`        |
| Elastic Query (remote) | Not required    | `<remote_server_name>.database.windows.net`           |

Location path:

- `<shard_map_server_name>` = The logical server name in Azure that is hosting the shard map manager. The `DATABASE_NAME` argument provides the database used to host the shard map and `SHARD_MAP_NAME` is used for the shard map itself.
- `<remote_server_name>` = The target logical server name for the elastic query. The database name is specified using the `DATABASE_NAME` argument.

Additional notes and guidance when setting the location:

- The [!INCLUDE[ssde_md](../../includes/ssde_md.md)] doesn't verify the existence of the external data source when the object is created. To validate, create an external table using the external data source.

### CREDENTIAL = *credential_name*

Specifies a database-scoped credential for authenticating to the external data source.

Additional notes and guidance when creating a credential:

- To load data from Azure Storage into [!INCLUDE[ssSDSfull](../../includes/sssdsfull-md.md)], use an Azure Storage Key.
- `CREDENTIAL` is only required if the data has been secured. `CREDENTIAL` isn't required for data sets that allow anonymous access.
- When the `TYPE` = `BLOB_STORAGE` the credential must be created using `SHARED ACCESS SIGNATURE` as the identity. Furthermore, the SAS token should be configured as follows:
  - Exclude the leading `?` when configured as the secret
  - Have at least read permission on the file that should be loaded (for example `srt=o&sp=r`)
  - Use a valid expiration period (all dates are in UTC time).

For an example of using a `CREDENTIAL` with `SHARED ACCESS SIGNATURE` and `TYPE` = `BLOB_STORAGE`, see [Create an external data source to execute bulk operations and retrieve data from Azure Storage into SQL Database](#c-create-an-external-data-source-for-bulk-operations-retrieving-data-from-azure-storage)

To create a database scoped credential, see [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)][create_dsc].

### TYPE = *[ BLOB_STORAGE | RDBMS | SHARD_MAP_MANAGER]*

Specifies the type of the external data source being configured. This parameter isn't always required.

- Use `RDBMS` for cross-database queries using elastic query from SQL Database.
- Use `SHARD_MAP_MANAGER` when creating an external data source when connecting to a sharded SQL Database.
- Use `BLOB_STORAGE` when executing bulk operations with [BULK INSERT][bulk_insert], or [OPENROWSET][openrowset].

> [!IMPORTANT]
> Do not set `TYPE` if using any other external data source.

### DATABASE_NAME = *database_name*

Configure this argument when the `TYPE` is set to `RDBMS` or `SHARD_MAP_MANAGER`.

| TYPE              | Value of DATABASE_NAME                                       |
| ----------------- | ------------------------------------------------------------ |
| RDBMS             | The name of the remote database on the server provided using `LOCATION` |
| SHARD_MAP_MANAGER | Name of the database operating as the shard map manager      |

For an example showing how to create an external data source where `TYPE` = `RDBMS` refer to [Create an RDBMS external data source](#b-create-an-rdbms-external-data-source)

### SHARD_MAP_NAME = *shard_map_name*

Used when the `TYPE` argument is set to `SHARD_MAP_MANAGER` only to set the name of the shard map.

For an example showing how to create an external data source where `TYPE` = `SHARD_MAP_MANAGER` refer to [Create a shard map manager external data source](#a-create-a-shard-map-manager-external-data-source)

## Permissions

Requires `CONTROL` permission on database in [!INCLUDE[ssSDSfull](../../includes/sssdsfull-md.md)].

## Locking

Takes a shared lock on the `EXTERNAL DATA SOURCE` object.

## Examples:

### A. Create a shard map manager external data source

To create an external data source to reference a SHARD_MAP_MANAGER, specify the SQL Database server name that hosts the shard map manager in SQL Database or a SQL Server database on a virtual machine.

```sql
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<password>' ;

CREATE DATABASE SCOPED CREDENTIAL ElasticDBQueryCred
WITH
  IDENTITY = '<username>',
  SECRET = '<password>' ;

CREATE EXTERNAL DATA SOURCE MyElasticDBQueryDataSrc
WITH
  ( TYPE = SHARD_MAP_MANAGER ,
    LOCATION = '<server_name>.database.windows.net' ,
    DATABASE_NAME = 'ElasticScaleStarterKit_ShardMapManagerDb' ,
    CREDENTIAL = ElasticDBQueryCred ,
    SHARD_MAP_NAME = 'CustomerIDShardMap'
  ) ;
```

For a step-by-step tutorial, see [Getting started with elastic queries for sharding (horizontal partitioning)][sharded_eq_tutorial].

### B. Create an RDBMS external data source

To create an external data source to reference an RDBMS, specifies the SQL Database server name of the remote database in SQL Database.

```sql
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<password>' ;

CREATE DATABASE SCOPED CREDENTIAL SQL_Credential
WITH
  IDENTITY = '<username>' ,
  SECRET = '<password>' ;

CREATE EXTERNAL DATA SOURCE MyElasticDBQueryDataSrc
WITH
  ( TYPE = RDBMS ,
    LOCATION = '<server_name>.database.windows.net' ,
    DATABASE_NAME = 'Customers' ,
    CREDENTIAL = SQL_Credential
  ) ;
```

For a step-by-step tutorial on RDBMS, see [Getting started with cross-database queries (vertical partitioning)][remote_eq_tutorial].

## Examples: Bulk Operations

> [!IMPORTANT]
> Do not add a trailing **/**, file name, or shared access signature parameters at the end of the `LOCATION` URL when configuring an external data source for bulk operations.

### C. Create an external data source for bulk operations retrieving data from Azure Storage

Use the following data source for bulk operations using [BULK INSERT][bulk_insert] or [OPENROWSET][openrowset]. The credential must set `SHARED ACCESS SIGNATURE` as the identity, mustn't have the leading `?` in the SAS token, must have at least read permission on the file that should be loaded (for example `srt=o&sp=r`), and the expiration period should be valid (all dates are in UTC time). For more information on shared access signatures, see [Using Shared Access Signatures (SAS)][sas_token].

```sql
CREATE DATABASE SCOPED CREDENTIAL AccessAzureInvoices
WITH
  IDENTITY = 'SHARED ACCESS SIGNATURE',
  -- Remove ? from the beginning of the SAS token
  SECRET = '******srt=sco&sp=rwac&se=2017-02-01T00:55:34Z&st=2016-12-29T16:55:34Z***************' ;

CREATE EXTERNAL DATA SOURCE MyAzureInvoices
WITH
  ( LOCATION = 'https://newinvoices.blob.core.windows.net/week3' ,
    CREDENTIAL = AccessAzureInvoices ,
    TYPE = BLOB_STORAGE
  ) ;
```

To see this example in use, see [BULK INSERT][bulk_insert_example].

## See Also

- [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)][create_dsc]
- [CREATE EXTERNAL TABLE (Transact-SQL)][create_etb]
- [sys.external_data_sources (Transact-SQL)][cat_eds]
- [Using Shared Access Signatures (SAS)][sas_token]
- [Introduction to elastic query][intro_eq]

<!-- links to external pages -->
<!-- SQL Docs -->
[bulk_insert]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql
[bulk_insert_example]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql#f-importing-data-from-a-file-in-azure-storage
[openrowset]: https://docs.microsoft.com/sql/t-sql/functions/openrowset-transact-sql
[create_dsc]: https://docs.microsoft.com/sql/t-sql/statements/create-database-scoped-credential-transact-sql
[create_etb]: https://docs.microsoft.com/sql/t-sql/statements/create-external-data-source
[alter_eds]: https://docs.microsoft.com/sql/t-sql/statements/alter-external-data-source-transact-sql
[cat_eds]: https://docs.microsoft.com/sql/relational-databases/system-catalog-views/sys-external-data-sources-transact-sql
<!-- PolyBase docs -->
[intro_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-guide
[mongodb_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-configure-mongodb
[connectivity_pb]:https://docs.microsoft.com/sql/database-engine/configure-windows/polybase-connectivity-configuration-transact-sql
[connection_options]: https://docs.microsoft.com/sql/relational-databases/native-client/applications/using-connection-string-keywords-with-sql-server-native-client
[hint_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-pushdown-computation#force-pushdown
<!-- Elastic Query Docs -->
[intro_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-overview/
[remote_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started-vertical/
[remote_eq_tutorial]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started-vertical/
[sharded_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started/
[sharded_eq_tutorial]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started/

<!-- Azure Docs -->
[azure_ad]: https://docs.microsoft.com/azure/data-lake-store/data-lake-store-authenticate-using-active-directory
[sas_token]: https://docs.microsoft.com/azure/storage/storage-dotnet-shared-access-signature-part-1

::: moniker-end
::: moniker range="=azure-sqldw-latest||=sqlallproducts-allversions"

:::row:::
    :::column:::
        [SQL Server](create-external-data-source-transact-sql.md?view=sql-server-2017)
    :::column-end:::
    :::column:::
        [SQL Database](create-external-data-source-transact-sql.md?view=azuresqldb-current)
    :::column-end:::
    :::column:::
        **_\* Azure Synapse<br />Analytics \*_** &nbsp;
    :::column-end:::
    :::column:::
        [Analytics Platform<br />System (PDW)](create-external-data-source-transact-sql.md?view=aps-pdw-2016-au7)
    :::column-end:::
:::row-end:::

&nbsp;

## Overview: Azure Synapse Analytics

Creates an external data source for PolyBase. External data sources are used to establish connectivity and support the following primary use case: Data virtualization and data load using [PolyBase][intro_pb]

> [!IMPORTANT]  
> To create an external data source to query a SQL Analytics resource using Azure SQL Database with [elastic query][remote_eq], see [SQL Database](create-external-data-source-transact-sql.md?view=azuresqldb-current).

## Syntax

```syntaxsql
CREATE EXTERNAL DATA SOURCE <data_source_name>
WITH
  ( [ LOCATION = '<prefix>://<path>[:<port>]' ]
    [ [ , ] CREDENTIAL = <credential_name> ]
    [ [ , ] TYPE = HADOOP ]
[ ; ]
```

## Arguments

### data_source_name

Specifies the user-defined name for the data source. The name must be unique within the [!INCLUDE[ssazure_md](../../includes/ssazure_md.md)] in [!INCLUDE[ssSDW](../../includes/sssdw-md.md)].

### LOCATION = *`'<prefix>://<path[:port]>'`*

Provides the connectivity protocol and path to the external data source.

| External Data Source        | Location prefix | Location path                                         |
| --------------------------- | --------------- | ----------------------------------------------------- |
| Azure Data Lake Store Gen 1 | `adl`           | `<storage_account>.azuredatalake.net`                 |
| Azure Data Lake Store Gen 2 | `abfs[s]`       | `<container>@<storage_account>.dfs.core.windows.net`  |
| Azure V2 Storage account    | `wasb[s]`       | `<container>@<storage_account>.blob.core.windows.net` |

Location path:

- `<container>` = the container of the storage account holding the data. Root containers are read-only, data can't be written back to the container.
- `<storage_account>` = the storage account name of the azure resource.

Additional notes and guidance when setting the location:

- The default option is to use `enable secure SSL connections` when provisioning Azure Data Lake Storage Gen 2. When this is enabled, you must use `abfss` when a secure TLS/SSL connection is selected. Note `abfss`works for unsecure TLS connections as well.
- Azure Synapse doesn't verify the existence of the external data source when the object is created. . To validate, create an external table using the external data source.
- Use the same external data source for all tables when querying Hadoop to ensure consistent querying semantics.
- `wasbs` is recommended as data will be sent using a secure TLS connection
- Hierarchical Namespaces aren't supported with Azure V2 Storage Accounts when accessing data via PolyBase using the wasb:// interface.

### CREDENTIAL = *credential_name*

Specifies a database-scoped credential for authenticating to the external data source.

Additional notes and guidance when creating a credential:

- To load data from Azure Storage or Azure Data Lake Store (ADLS) Gen 2 into SQL DW, use an Azure Storage Key.
- `CREDENTIAL` is only required if the data has been secured. `CREDENTIAL` isn't required for data sets that allow anonymous access.

To create a database scoped credential, see [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)][create_dsc].

### TYPE = *HADOOP*

Specifies the type of the external data source being configured. This parameter isn't always required.

- Use HADOOP when the external data source is Azure Storage, ADLS Gen 1, or ADLS Gen 2.

For an example of using `TYPE` = `HADOOP` to load data from Azure Storage, see [Create external data source to reference Azure Data Lake Store Gen 1 or 2 using a service principal](#b-create-external-data-source-to-reference-azure-data-lake-store-gen-1-or-2-using-a-service-principal).

## Permissions

Requires `CONTROL` permission on the database.

## Locking

Takes a shared lock on the `EXTERNAL DATA SOURCE` object.

## Security

PolyBase supports proxy based authentication for most external data sources. Create a database scoped credential to create the proxy account.

When you connect to the storage or data pool in a SQL Server big data cluster, the user's credentials are passed through to the back-end system. Create logins in the data pool itself to enable pass through authentication.

Currently a SAS token with type `HADOOP` is unsupported. It's only supported with a storage account access key. Attempting to create an external data source with type `HADOOP` and a SAS credential fails with the following error:

`Msg 105019, Level 16, State 1 - EXTERNAL TABLE access failed due to internal error: 'Java exception raised on call to HdfsBridge_Connect. Java exception message: Parameters provided to connect to the Azure storage account are not valid.: Error [Parameters provided to connect to the Azure storage account are not valid.] occurred while accessing external file.'`

## Examples:

### A. Create external data source to access data in Azure Storage using the wasb:// interface
In this example, the external data source is an Azure V2 Storage account named `logs`. The container is called `daily`. The Azure Storage external data source is for data transfer only. It doesn't support predicate push-down. Hierarchical namespaces are not supported when accessing data via the the `wasb://` interface.

This example shows how to create the database scoped credential for authentication to Azure Storage. Specify the Azure Storage account key in the database credential secret. You can specify any string in database scoped credential identity as it isn't used during authentication to Azure storage.

```sql
-- Create a database master key if one does not already exist, using your own password. This key is used to encrypt the credential secret in next step.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'S0me!nfo' ;

-- Create a database scoped credential with Azure storage account key as the secret.
CREATE DATABASE SCOPED CREDENTIAL AzureStorageCredential
WITH
  IDENTITY = '<my_account>',
  SECRET = '<azure_storage_account_key>' ;

-- Create an external data source with CREDENTIAL option.
CREATE EXTERNAL DATA SOURCE MyAzureStorage
WITH
  ( LOCATION = 'wasbs://daily@logs.blob.core.windows.net/' ,
    CREDENTIAL = AzureStorageCredential ,
    TYPE = HADOOP
  ) ;
```

### B. Create external data source to reference Azure Data Lake Store Gen 1 or 2 using a service principal

Azure Data Lake Store connectivity can be based on your ADLS URI and your Azure Active directory Application's service principal. Documentation for creating this application can be found at [Data lake store authentication using Active Directory][azure_ad].

```sql
-- If you do not have a Master Key on your DW you will need to create one.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<password>' ;

-- These values come from your Azure Active Directory Application used to authenticate to ADLS
CREATE DATABASE SCOPED CREDENTIAL ADLS_credential
WITH
  -- IDENTITY = '<clientID>@<OAuth2.0TokenEndPoint>' ,
  IDENTITY = '536540b4-4239-45fe-b9a3-629f97591c0c@https://login.microsoftonline.com/42f988bf-85f1-41af-91ab-2d2cd011da47/oauth2/token' ,
  -- SECRET = '<KEY>'
  SECRET = 'BjdIlmtKp4Fpyh9hIvr8HJlUida/seM5kQ3EpLAmeDI=' 
;

-- For Gen 1 - Create an external data source
-- TYPE: HADOOP - PolyBase uses Hadoop APIs to access data in Azure Data Lake Storage.
-- LOCATION: Provide Data Lake Storage Gen 1 account name and URI
-- CREDENTIAL: Provide the credential created in the previous step
CREATE EXTERNAL DATA SOURCE AzureDataLakeStore
WITH
  ( LOCATION = 'adl://newyorktaxidataset.azuredatalakestore.net' ,
    CREDENTIAL = ADLS_credential ,
    TYPE = HADOOP
  ) ;

-- For Gen 2 - Create an external data source
-- TYPE: HADOOP - PolyBase uses Hadoop APIs to access data in Azure Data Lake Storage.
-- LOCATION: Provide Data Lake Storage Gen 2 account name and URI
-- CREDENTIAL: Provide the credential created in the previous step
CREATE EXTERNAL DATA SOURCE AzureDataLakeStore
WITH
  -- Please note the abfss endpoint when your account has secure transfer enabled
  ( LOCATION = 'abfss://data@newyorktaxidataset.dfs.core.windows.net' , 
    CREDENTIAL = ADLS_credential ,
    TYPE = HADOOP
  ) ;
```

### C. Create external data source to reference Azure Data Lake Store Gen 2 using the storage account key

```sql
-- If you do not have a Master Key on your DW you will need to create one.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<password>' ;

CREATE DATABASE SCOPED CREDENTIAL ADLS_credential
WITH
-- IDENTITY = '<storage_account_name>' ,
  IDENTITY = 'newyorktaxidata' ,
-- SECRET = '<storage_account_key>'
  SECRET = 'yz5N4+bxSb89McdiysJAzo+9hgEHcJRJuXbF/uC3mhbezES/oe00vXnZEl14U0lN3vxrFKsphKov16C0w6aiTQ=='
;

-- Note this example uses a Gen 2 secured endpoint (abfss)
CREATE EXTERNAL DATA SOURCE <data_source_name>
WITH
  ( LOCATION = 'abfss://2013@newyorktaxidataset.dfs.core.windows.net' ,
    CREDENTIAL = ADLS_credential ,
    TYPE = HADOOP
  ) ;
```

### D. Create external data source to reference Polybase connectivity to Azure Data Lake Store Gen 2 using abfs://

There is no need to specify SECRET when connecting to Azure Data Lake Store Gen2 account with [Managed Identity](/azure/active-directory/managed-identities-azure-resources/overview
) mechanism.

```sql
-- If you do not have a Master Key on your DW you will need to create one
CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<password>' ;

--Create database scoped credential with **IDENTITY = 'Managed Service Identity'**

CREATE DATABASE SCOPED CREDENTIAL msi_cred 
WITH IDENTITY = 'Managed Service Identity' ;

--Create external data source with abfss:// scheme for connecting to your Azure Data Lake Store Gen2 account

CREATE EXTERNAL DATA SOURCE ext_datasource_with_abfss 
WITH 
  ( TYPE = HADOOP , 
    LOCATION = 'abfss://myfile@mystorageaccount.dfs.core.windows.net' , 
    CREDENTIAL = msi_cred
  ) ;
```

## See Also

- [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)][create_dsc]
- [CREATE EXTERNAL FILE FORMAT (Transact-SQL)][create_eff]
- [CREATE EXTERNAL TABLE (Transact-SQL)][create_etb]
- [CREATE EXTERNAL TABLE AS SELECT (Azure Synapse Analytics)][create_etb_as_sel]
- [CREATE TABLE AS SELECT (Azure Synapse Analytics)][create_tbl_as_sel]
- [sys.external_data_sources (Transact-SQL)][cat_eds]
- [Using Shared Access Signatures (SAS)][sas_token]

<!-- links to external pages -->
<!-- SQL Docs -->
[bulk_insert]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql
[bulk_insert_example]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql#f-importing-data-from-a-file-in-azure-storage
[openrowset]: https://docs.microsoft.com/sql/t-sql/functions/openrowset-transact-sql

[create_dsc]: https://docs.microsoft.com/sql/t-sql/statements/create-database-scoped-credential-transact-sql
[create_eff]: https://docs.microsoft.com/sql/t-sql/statements/create-external-file-format-transact-sql
[create_etb]: https://docs.microsoft.com/sql/t-sql/statements/create-external-data-source
[create_etb_as_sel]: https://docs.microsoft.com/sql/t-sql/statements/create-external-table-as-select-transact-sql?view=azure-sqldw-latest
[create_tbl_as_sel]: https://docs.microsoft.com/sql/t-sql/statements/create-table-as-select-azure-sql-data-warehouse?view=azure-sqldw-latest

[alter_eds]: https://docs.microsoft.com/sql/t-sql/statements/alter-external-data-source-transact-sql

[cat_eds]: https://docs.microsoft.com/sql/relational-databases/system-catalog-views/sys-external-data-sources-transact-sql
<!-- PolyBase docs -->
[intro_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-guide
[mongodb_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-configure-mongodb
[connectivity_pb]:https://docs.microsoft.com/sql/database-engine/configure-windows/polybase-connectivity-configuration-transact-sql
[connection_options]: https://docs.microsoft.com/sql/relational-databases/native-client/applications/using-connection-string-keywords-with-sql-server-native-client
[hint_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-pushdown-computation#force-pushdown
<!-- Elastic Query Docs -->
[intro_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-overview/
[remote_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started-vertical/
[remote_eq_tutorial]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started-vertical/
[sharded_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started/
[sharded_eq_tutorial]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started/

<!-- Azure Docs -->
[azure_ad]: https://docs.microsoft.com/azure/data-lake-store/data-lake-store-authenticate-using-active-directory
[sas_token]: https://docs.microsoft.com/azure/storage/storage-dotnet-shared-access-signature-part-1

::: moniker-end
::: moniker range=">=aps-pdw-2016||=sqlallproducts-allversions"

:::row:::
    :::column:::
        [SQL Server](create-external-data-source-transact-sql.md?view=sql-server-2017)
    :::column-end:::
    :::column:::
        [SQL Database](create-external-data-source-transact-sql.md?view=azuresqldb-current)
    :::column-end:::
    :::column:::
        [Azure Synapse<br />Analytics](create-external-data-source-transact-sql.md?view=azure-sqldw-latest)
    :::column-end:::
    :::column:::
        **_\* Analytics<br />Platform System (PDW) \*_** &nbsp;
    :::column-end:::
:::row-end:::

&nbsp;

## Overview: Analytics Platform System

Creates an external data source for PolyBase queries. External data sources are used to establish connectivity and support the following use case: Data virtualization and data load using [PolyBase][intro_pb]

## Syntax

```syntaxsql
CREATE EXTERNAL DATA SOURCE <data_source_name>
WITH
  ( [ LOCATION = '<prefix>://<path>[:<port>]' ]
    [ [ , ] CREDENTIAL = <credential_name> ]
    [ [ , ] TYPE = HADOOP ]
    [ [ , ] RESOURCE_MANAGER_LOCATION = '<resource_manager>[:<port>]' )
[ ; ]
```

## Arguments

### data_source_name

Specifies the user-defined name for the data source. The name must be unique within the server in [!INCLUDE[ssPDW](../../includes/sspdw-md.md)].

### LOCATION = *`'<prefix>://<path[:port]>'`*

Provides the connectivity protocol and path to the external data source.

| External Data Source    | Location prefix | Location path                                         |
| ----------------------- | --------------- | ----------------------------------------------------- |
| Cloudera or Hortonworks | `hdfs`          | `<Namenode>[:port]`                                   |
| Azure Storage Account   | `wasb[s]`       | `<container>@<storage_account>.blob.core.windows.net` |

Location path:

- `<Namenode>` = the machine name, name service URI, or IP address of the `Namenode` in the Hadoop cluster. PolyBase must resolve any DNS names used by the Hadoop cluster. <!-- For highly available Hadoop configurations, provide the Nameservice ID as the `LOCATION`. -->
- `port` = The port that the external data source is listening on. In Hadoop, the port can be found using the `fs.defaultFS` configuration parameter. The default is 8020.
- `<container>` = the container of the storage account holding the data. Root containers are read-only, data can't be written back to the container.
- `<storage_account>` = the storage account name of the azure resource.

Additional notes and guidance when setting the location:

- The PDW engine doesn't verify the existence of the external data source when the object is created. To validate, create an external table using the external data source.
- Use the same external data source for all tables when querying Hadoop to ensure consistent querying semantics.
- `wasbs` is recommended as data will be sent using a secure TLS connection.
- Hierarchical Namespaces are not supported when used with Azure Storage accounts over wasb://.
- To ensure successful PolyBase queries during a Hadoop `Namenode` fail-over, consider using a virtual IP address for the `Namenode` of the Hadoop cluster. If you don't, execute an [ALTER EXTERNAL DATA SOURCE][alter_eds] command to point to the new location.

### CREDENTIAL = *credential_name*

Specifies a database-scoped credential for authenticating to the external data source.

Additional notes and guidance when creating a credential:

- To load data from Azure Storage into Azure Synapse or PDW, use an Azure Storage Key.
- `CREDENTIAL` is only required if the data has been secured. `CREDENTIAL` isn't required for data sets that allow anonymous access.

### TYPE = *[ HADOOP ]*

Specifies the type of the external data source being configured. This parameter isn't always required.

- Use HADOOP when the external data source is Cloudera, Hortonworks, or Azure Storage.

For an example of using `TYPE` = `HADOOP` to load data from Azure Storage, see [Create external data source to reference Hadoop](#a-create-external-data-source-to-reference-hadoop).

### RESOURCE_MANAGER_LOCATION = *'ResourceManager_URI[:port]'*

Configure this optional value when connecting to Hortonworks or Cloudera.

When the `RESOURCE_MANAGER_LOCATION` is defined, the query optimizer will make a cost-based decision to improve performance. A MapReduce job can be used to push down the computation to Hadoop. Specifying the `RESOURCE_MANAGER_LOCATION` can significantly reduce the volume of data transferred between Hadoop and SQL, which can lead to improved query performance.

If the Resource Manager isn't specified, pushing compute to Hadoop is disabled for PolyBase queries.

If the port isn't specified, the default value is chosen using the current setting for 'hadoop connectivity' configuration.

| Hadoop Connectivity | Default Resource Manager Port |
| ------------------- | ----------------------------- |
| 1                   | 50300                         |
| 2                   | 50300                         |
| 3                   | 8021                          |
| 4                   | 8032                          |
| 5                   | 8050                          |
| 6                   | 8032                          |
| 7                   | 8050                          |

For a complete list of supported Hadoop versions, see [PolyBase Connectivity Configuration (Transact-SQL)][connectivity_pb].

> [!IMPORTANT]
> The `RESOURCE_MANAGER_LOCATION` value is not validated when you create the external data source. Entering an incorrect value may cause query failure at execution time whenever push-down is attempted as the provided value would not be able to resolve.

[Create external data source to reference Hadoop with push-down enabled](#b-create-external-data-source-to-reference-hadoop-with-push-down-enabled) provides a concrete example and further guidance.

## Permissions

Requires `CONTROL` permission on database in [!INCLUDE[ssPDW](../../includes/sspdw-md.md)].

> [!NOTE]
> In previous releases of PDW, create external data source required `ALTER ANY EXTERNAL DATA SOURCE` permissions.

## Locking

Takes a shared lock on the `EXTERNAL DATA SOURCE` object.

## Security

PolyBase supports proxy based authentication for most external data sources. Create a database scoped credential to create the proxy account.

Currently a SAS token with type `HADOOP` is unsupported. It's only supported with a storage account access key. Attempting to create an external data source with type `HADOOP` and a SAS credential fails with the following error:

`Msg 105019, Level 16, State 1 - EXTERNAL TABLE access failed due to internal error: 'Java exception raised on call to HdfsBridge_Connect. Java exception message: Parameters provided to connect to the Azure storage account are not valid.: Error [Parameters provided to connect to the Azure storage account are not valid.] occurred while accessing external file.'`

## Examples:

### A. Create external data source to reference Hadoop

To create an external data source to reference your Hortonworks or Cloudera Hadoop cluster, specify the machine name, or IP address of the Hadoop `Namenode` and port. <!-- Provide the Nameservice ID as the `LOCATION` for highly available configurations. -->

```sql
CREATE EXTERNAL DATA SOURCE MyHadoopCluster
WITH
  ( LOCATION = 'hdfs://10.10.10.10:8050' ,
    TYPE = HADOOP
  ) ;
```

### B. Create external data source to reference Hadoop with push-down enabled

Specify the `RESOURCE_MANAGER_LOCATION` option to enable push-down computation to Hadoop for PolyBase queries. Once enabled, PolyBase makes a cost-based decision to determine whether the query computation should be pushed to Hadoop.

```sql
CREATE EXTERNAL DATA SOURCE MyHadoopCluster
WITH
  ( LOCATION = 'hdfs://10.10.10.10:8020'
    TYPE = HADOOP
    RESOURCE_MANAGER_LOCATION = '10.10.10.10:8050'
) ;
```

### C. Create external data source to reference Kerberos-secured Hadoop

To verify if the Hadoop cluster is Kerberos-secured, check the value of hadoop.security.authentication property in Hadoop core-site.xml. To reference a Kerberos-secured Hadoop cluster, you must specify a database scoped credential that contains your Kerberos username and password. The database master key is used to encrypt the database scoped credential secret.

```sql
-- Create a database master key if one does not already exist, using your own password. This key is used to encrypt the credential secret in next step.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'S0me!nfo' ;

-- Create a database scoped credential with Kerberos user name and password.
CREATE DATABASE SCOPED CREDENTIAL HadoopUser1
WITH
  IDENTITY = '<hadoop_user_name>' ,
  SECRET = '<hadoop_password>' ;

-- Create an external data source with CREDENTIAL option.
CREATE EXTERNAL DATA SOURCE MyHadoopCluster
WITH
  ( LOCATION = 'hdfs://10.10.10.10:8050' ,
    CREDENTIAL = HadoopUser1 ,
    TYPE = HADOOP ,
    RESOURCE_MANAGER_LOCATION = '10.10.10.10:8050'
  ) ;
```

### D. Create external data source to access data in Azure Storage using the wasb:// interface

In this example, the external data source is an Azure V2 Storage account named `logs`. The container is called `daily`. The Azure Storage external data source is for data transfer only. It doesn't support predicate push-down. Hierarchical namespaces are not supported when accessing data via the the `wasb://` interface.

This example shows how to create the database scoped credential for authentication to Azure storage. Specify the Azure storage account key in the database credential secret. You can specify any string in database scoped credential identity as it isn't used during authentication to Azure storage.

```sql
-- Create a database master key if one does not already exist, using your own password. This key is used to encrypt the credential secret in next step.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'S0me!nfo' ;

-- Create a database scoped credential with Azure storage account key as the secret.
CREATE DATABASE SCOPED CREDENTIAL AzureStorageCredential
WITH
  IDENTITY = '<my_account>' ,
  SECRET = '<azure_storage_account_key>' ;

-- Create an external data source with CREDENTIAL option.
CREATE EXTERNAL DATA SOURCE MyAzureStorage
WITH
  ( LOCATION = 'wasbs://daily@logs.blob.core.windows.net/'
    CREDENTIAL = AzureStorageCredential
    TYPE = HADOOP
  ) ;
```


## See Also

- [CREATE DATABASE SCOPED CREDENTIAL (Transact-SQL)][create_dsc]
- [CREATE EXTERNAL FILE FORMAT (Transact-SQL)][create_eff]
- [CREATE EXTERNAL TABLE (Transact-SQL)][create_etb]
- [sys.external_data_sources (Transact-SQL)][cat_eds]
- [Using Shared Access Signatures (SAS)][sas_token]

<!-- links to external pages -->
<!-- SQL Docs -->
[bulk_insert]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql
[bulk_insert_example]: https://docs.microsoft.com/sql/t-sql/statements/bulk-insert-transact-sql#f-importing-data-from-a-file-in-azure-storage
[openrowset]: https://docs.microsoft.com/sql/t-sql/functions/openrowset-transact-sql

[create_dsc]: https://docs.microsoft.com/sql/t-sql/statements/create-database-scoped-credential-transact-sql
[create_eff]: https://docs.microsoft.com/sql/t-sql/statements/create-external-file-format-transact-sql
[create_etb]: https://docs.microsoft.com/sql/t-sql/statements/create-external-data-source
[create_etb_as_sel]: https://docs.microsoft.com/sql/t-sql/statements/create-external-table-as-select-transact-sql?view=azure-sqldw-latest
[create_tbl_as_sel]: https://docs.microsoft.com/sql/t-sql/statements/create-table-as-select-azure-sql-data-warehouse?view=azure-sqldw-latest

[alter_eds]: https://docs.microsoft.com/sql/t-sql/statements/alter-external-data-source-transact-sql

[cat_eds]: https://docs.microsoft.com/sql/relational-databases/system-catalog-views/sys-external-data-sources-transact-sql
<!-- PolyBase docs -->
[intro_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-guide
[mongodb_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-configure-mongodb
[connectivity_pb]:https://docs.microsoft.com/sql/database-engine/configure-windows/polybase-connectivity-configuration-transact-sql
[connection_options]: https://docs.microsoft.com/sql/relational-databases/native-client/applications/using-connection-string-keywords-with-sql-server-native-client
[hint_pb]: https://docs.microsoft.com/sql/relational-databases/polybase/polybase-pushdown-computation#force-pushdown
<!-- Elastic Query Docs -->
[intro_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-overview/
[remote_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started-vertical/
[remote_eq_tutorial]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started-vertical/
[sharded_eq]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started/
[sharded_eq_tutorial]: https://azure.microsoft.com/documentation/articles/sql-database-elastic-query-getting-started/

<!-- Azure Docs -->
[azure_ad]: https://docs.microsoft.com/azure/data-lake-store/data-lake-store-authenticate-using-active-directory
[sas_token]: https://docs.microsoft.com/azure/storage/storage-dotnet-shared-access-signature-part-1

::: moniker-end