CREATE LINK

Syntax

CREATE LINK [IF NOT EXISTS] [db_name.]connection_name AS
{ S3 | AZURE | GCS | HDFS | HTTP | KAFKA | MONGODB | MYSQL }
CREDENTIALS 'credentials_json'
[ CONFIG 'configuration_json' ]
[ DESCRIPTION 'description' ]

Remarks

db_name is the name of the SingleStore Helios database. It is an optional parameter. If not specified, the connection link is created in the current (context) database.
CONFIG and CREDENTIALS can be specified in either order (CONFIG followed by CREDENTIALS or CREDENTIALS followed by CONFIG).
The CONFIG and CREDENTIALS expect json formatted information. Refer to the examples below. For more configuration examples, refer to BACKUP DATABASE.
connection_name is a user defined name of the connection link.
Only users with CREATE LINK permission can create a connection link.
description specifies the details related to the connection link.
Commands such as BACKUP, RESTORE, CREATE PIPELINE, and SELECT support connection links. Refer to any of these commands for details on the credentials_json and configuration_json clauses.
This command causes implicit commits. Refer to COMMIT for more information.
This command can be used to create regular and encrypted HTTP links. Refer to Using HTTP connection links for more information and examples.
Refer to the Permission Matrix for the required permission.

Examples

AWS S3 Example

The configuration_json and credentials_json for AWS connections look like this:

CREDENTIALS '{
  "aws_access_key_id": "replace_with_your_access_key_id",
  "aws_secret_access_key": "replace_with_your_secret_access_key"
  [, "aws_session_token": "replace_with_your_temp_session_token"]
  [, "role_arn":"replace_with_your_role_arn"]
}'

CONFIG: ‘{
  "region": "your_region",
  "endpoint_url": "http://other_endpoint"
  [,"x-amz-server-side-encryption":"<encryption_type>" [, "x-amz-server-side-encryption-aws-kms-key-id":"<optional_key>" ] |
  "x-amz-server-side-encryption-customer-algorithm":"<encryption_type>",
  "x-amz-server-side-encryption-customer-key":"<encrypted_or_unencrypted_key>",
  "x-amz-server-side-encryption-customer-key-MD5":"<key>"
  ]
}'

For other options for the CONFIG clause (disable_gunzip, request_payer, and others) see CREATE PIPELINE.

The following example demonstrates how to create an S3 connection link product_S3 to the database Orderdb.

SQL

CREATE LINK Orderdb.product_S3 AS S3
CREDENTIALS '{"aws_access_key_id":"your_access_key_id",
              "aws_secret_access_key":"your_secret_access_key"}'
CONFIG '{"region":"us-east-1"}'
DESCRIPTION 'Products ordered in December';

Azure Example

The credentials_json for Azure looks like this:

CREDENTIALS '{
  "account_name": "your_account_name",
  "account_key": "encrypted_key"
}';

The following example shows how to create an Azure connection link.

SQL

CREATE LINK [db_name.]connection_name AS AZURE
CREDENTIALS '{
  "account_name": "your_account",
  "account_key": "encrypted_key"
}';

For more information about Azure credentials, see Azure Blob Pipeline Syntax.

GCS Example

The credentials_json for GCS looks like this:

CREDENTIALS '{
  "access_id": "your_google_access_key", 
  "secret_key": "your_google_secret_key"
};

The following example demonstrates how to create a GCS connection link called mylink.

SQL

CREATE LINK mylink AS GCS CREDENTIALS '{
  "access_id": "your_google_access_key",
  "secret_key": "your_google_secret_key"
}';

For more information about GCS credentials, see CREATE PIPELINE.

HDFS Example

The login for HDFS cluster is performed via a keytab file, so typically credentials_json is left blank and config_json is used. The following example demonstrates how to create an HDFS link called mylink:

SQL

CREATE LINK mylink AS HDFS
CREDENTIALS ''
CONFIG '{
      "hadoop.security.authentication": "kerberos",
      "kerberos.user": "user@masked_host",
      "kerberos.keytab": "/opt/software/adkeytabs/user.keytab",
      "dfs.client.use.datanode.hostname": true,
      "dfs.datanode.kerberos.principal": "hdfs/_HOST@masked_host",
      "dfs.namenode.kerberos.principal": "hdfs/_HOST@masked_host"       
}';

For more information about HDFS credentials, see Advanced HDFS Pipeline Mode.

HTTP Example

The following example demonstrates how to create an HTTP link.

SQL

CREATE LINK test AS HTTP CREDENTIALS '{"headers": {"Authorization": "Basic cm9vdDp0ZXN0aW5nCg=="}}';

Refer to Using HTTP connection links for more information and examples.

Kafka Example

The credentials_json and config_json for Kafka can be complex. See CREATE PIPELINE for more information.

The following example demonstrates how to create a Kafka connection link for Confluent Cloud.

SQL

CREATE LINK mylink AS KAFKA
CONFIG '{
  "security.protocol": "sasl_ssl",
  "sasl.mechanism": "PLAIN"
}'
CREDENTIALS '{
  "sasl.username": "your_sasl_username",
  "sasl.password": "your_sasl_secret_key"
}';

MongoDB® Example

Here's a sample syntax to create a link to a MongoDB® endpoint:

SQL

CREATE LINK <linkname> AS MONGODB
CONFIG '{
  "mongodb.hosts":"<Hostname>",
  "collection.include.list": "<Collection list>",
  "mongodb.ssl.enabled":"true",
  "mongodb.authsource":"admin"}'
CREDENTIALS '{
  "mongodb.user":"<username>",
  "mongodb.password":"<password>"}';

For more information, refer to Replicate MongoDB® Collections using SQL.

MySQL Example

Here's a sample syntax to create a link to a MySQL endpoint:

SQL

CREATE LINK <linkname> AS MYSQL 
CONFIG '{
  "database.hostname": "<Hostname>", 
  "database.exclude.list": "<database_list>", 
  "database.port": 3306, 
  "database.ssl.mode":"required"}' 
CREDENTIALS '{
  "database.password": "<password>", 
  "database.user": "<username>"}';

For more information, refer to Replicate Data from MySQL.