Connect to SingleStore Data as an External Data Source using PolyBase

PolyBase for SQL Server allows you to query external data by using the same Transact-SQL syntax used to query a database table. When paired with the CData ODBC Driver for SingleStore, you get access to your SingleStore data directly alongside your SQL Server data. This article describes creating an external data source and external tables to grant access to live SingleStore data using T-SQL queries.

NOTE: PolyBase is only available on SQL Server 19 and above, and only for Standard SQL Server.

CData Connect Cloud provides a pure SQL Server interface for SingleStore, allowing you to query data from SingleStore without replicating the data to a natively supported database. Using optimized data processing out of the box, CData Connect Cloud pushes all supported SQL operations (filters, JOINs, etc.) directly to SingleStore, leveraging server-side processing to return the requested SingleStore data quickly.

Configure SingleStore Connectivity for PolyBase

Connectivity to SingleStore from PolyBase is made possible through CData Connect Cloud. To work with SingleStore data from PolyBase, we start by creating and configuring a SingleStore connection.

1. Log into Connect Cloud, click Connections and click Add Connection
2. Select "SingleStore" from the Add Connection panel
3. Enter the necessary authentication properties to connect to SingleStore.

   The following connection properties are required in order to connect to data.

   • Server: The host name or IP of the server hosting the SingleStore database.
   • Port: The port of the server hosting the SingleStore database.
   • Database (Optional): The default database to connect to when connecting to the SingleStore Server. If this is not set, tables from all databases will be returned.

   Connect Using Standard Authentication

   To authenticate using standard authentication, set the following:

   • User: The user which will be used to authenticate with the SingleStore server.
   • Password: The password which will be used to authenticate with the SingleStore server.

   Connect Using Integrated Security

   As an alternative to providing the standard username and password, you can set IntegratedSecurity to True to authenticate trusted users to the server via Windows Authentication.

   Connect Using SSL Authentication

   You can leverage SSL authentication to connect to SingleStore data via a secure session. Configure the following connection properties to connect to data:

   • SSLClientCert: Set this to the name of the certificate store for the client certificate. Used in the case of 2-way SSL, where truststore and keystore are kept on both the client and server machines.
   • SSLClientCertPassword: If a client certificate store is password-protected, set this value to the store's password.
   • SSLClientCertSubject: The subject of the TLS/SSL client certificate. Used to locate the certificate in the store.
   • SSLClientCertType: The certificate type of the client store.
   • SSLServerCert: The certificate to be accepted from the server.

   Connect Using SSH Authentication

   Using SSH, you can securely login to a remote machine. To access SingleStore data via SSH, configure the following connection properties:

   • SSHClientCert: Set this to the name of the certificate store for the client certificate.
   • SSHClientCertPassword: If a client certificate store is password-protected, set this value to the store's password.
   • SSHClientCertSubject: The subject of the TLS/SSL client certificate. Used to locate the certificate in the store.
   • SSHClientCertType: The certificate type of the client store.
   • SSHPassword: The password that you use to authenticate with the SSH server.
   • SSHPort: The port used for SSH operations.
   • SSHServer: The SSH authentication server you are trying to authenticate against.
   • SSHServerFingerPrint: The SSH Server fingerprint used for verification of the host you are connecting to.
   • SSHUser: Set this to the username that you use to authenticate with the SSH server.
4. Click Create & Test
5. Navigate to the Permissions tab in the Add SingleStore Connection page and update the User-based permissions.

Add a Personal Access Token

If you are connecting from a service, application, platform, or framework that does not support OAuth authentication, you can create a Personal Access Token (PAT) to use for authentication. Best practices would dictate that you create a separate PAT for each service, to maintain granularity of access.

1. Click on your username at the top right of the Connect Cloud app and click User Profile.
2. On the User Profile page, scroll down to the Personal Access Tokens section and click Create PAT.
3. Give your PAT a name and click Create.
4. The personal access token is only visible at creation, so be sure to copy it and store it securely for future use.

Create an External Data Source for SingleStore Data

After configuring the connection, you need to create a credential database for the external data source.

Creating a Credential Database

Execute the following SQL command to create credentials for the external data source connected to SingleStore data.

NOTE: Set IDENTITY to your Connect Cloud username and set SECRET to your Personal Access Token.

CREATE DATABASE SCOPED CREDENTIAL ConnectCloudCredentials
WITH IDENTITY = 'yourusername', SECRET = 'yourPAT';

Create an External Data Source for SingleStore

Execute a CREATE EXTERNAL DATA SOURCE SQL command to create an external data source for SingleStore with PolyBase:

CREATE EXTERNAL DATA SOURCE ConnectCloudInstance
WITH ( 
  LOCATION = 'sqlserver://tds.cdata.com:14333',
  PUSHDOWN = ON,
  CREDENTIAL = ConnectCloudCredentials
);

Create External Tables for SingleStore

After creating the external data source, use CREATE EXTERNAL TABLE statements to link to SingleStore data from your SQL Server instance. The table column definitions must match those exposed by CData Connect Cloud. You can use the Data Explorer in Connect Cloud to see the table definition.

Sample CREATE TABLE Statement

Execute a CREATE EXTERNAL TABLE SQL command to create the external table(s), using the collation and setting the LOCATION to three-part notation for the connection, catalog, and table. The statement to create an external table based on a SingleStore Orders would look similar to the following.

CREATE EXTERNAL TABLE Orders(
  ShipName COLLATE [nvarchar](255) NULL,
  ShipCity COLLATE [nvarchar](255) NULL,
  ...
) WITH ( 
  LOCATION='SingleStore1.SingleStore.Orders',
  DATA_SOURCE=ConnectCloudInstance
);

Having created external tables for SingleStore in your SQL Server instance, you are now able to query local and remote data simultaneously. To get live data access to 100+ SaaS, Big Data, and NoSQL sources directly from your SQL Server database, try CData Connect Cloud today!