How to create Lakebase federated tables in MySQL

You can use the SQL Gateway to configure a MySQL remoting service and set up federated tables for Lakebase data. The service is a daemon process that provides a MySQL interface to the CData ODBC Driver for Lakebase: After you have started the service, you can create a server and tables using the FEDERATED Storage Engine in MySQL. You can then work with Lakebase data just as you would local MySQL tables.

Connect to Lakebase Data

If you have not already done so, provide values for the required connection properties in the data source name (DSN). You can use the built-in Microsoft ODBC Data Source Administrator to configure the DSN. This is also the last step of the driver installation. See the "Getting Started" chapter in the help documentation for a guide to using the Microsoft ODBC Data Source Administrator to create and configure a DSN.

• DatabricksInstance: The Databricks instance or server hostname, provided in the format instance-abcdef12-3456-7890-abcd-abcdef123456.database.cloud.databricks.com.
• Server: The host name or IP address of the server hosting the Lakebase database.
• Port (optional): The port of the server hosting the Lakebase database, set to 5432 by default.
• Database (optional): The database to connect to after authenticating to the Lakebase Server, set to the authenticating user's default database by default.

OAuth Client Authentication

To authenicate using OAuth client credentials, you need to configure an OAuth client in your service principal. In short, you need to do the following:

1. Create and configure a new service principal
2. Assign permissions to the service principal
3. Create an OAuth secret for the service principal

For more information, refer to the Setting Up OAuthClient Authentication section in the Help documentation.

OAuth PKCE Authentication

To authenticate using the OAuth code type with PKCE (Proof Key for Code Exchange), set the following properties:

• AuthScheme: OAuthPKCE.
• User: The authenticating user's user ID.

For more information, refer to the Help documentation.

Configure the SQL Gateway

See the SQL Gateway Overview to set up connectivity to Lakebase data as a virtual MySQL database. You will configure a MySQL remoting service that listens for MySQL requests from clients. The service can be configured in the SQL Gateway UI.

Create a FEDERATED Server and Tables for Lakebase Data

After you have configured and started the service, create a FEDERATED server to simplify the process of creating FEDERATED tables:

Create a FEDERATED Server

The following statement will create a FEDERATED server based on the ODBC Driver for Lakebase. Note that the username and password of the FEDERATED server must match a user account you defined on the Users tab of the SQL Gateway.

CREATE SERVER fedLakebase
FOREIGN DATA WRAPPER mysql
OPTIONS (USER 'sql_gateway_user', PASSWORD 'sql_gateway_passwd', HOST 'sql_gateway_host', PORT ####, DATABASE 'CData Lakebase Sys');

Create a FEDERATED Table

To create a FEDERATED table using our newly created server, use the CONNECTION keyword and pass the name of the FEDERATED server and the remote table (Orders). Refer to the following template for the statement to create a FEDERATED table:

CREATE TABLE fed_orders (
  ...,
  shipname  TYPE(LEN),
  shipcity  TYPE(LEN),
  ...,
)
ENGINE=FEDERATED
DEFAULT CHARSET=latin1
CONNECTION='fedLakebase/orders';

NOTE: The table schema for the FEDERATED table must match the remote table schema exactly. You can always connect directly to the MySQL remoting service using any MySQL client and run a SHOW CREATE TABLE query to get the table schema.

Execute Queries

You can now execute queries to the Lakebase FEDERATED tables from any tool that can connect to MySQL, which is particularly useful if you need to JOIN data from a local table with data from Lakebase. Refer to the following example:

SELECT 
  fed_orders.shipname, 
  local_table.custom_field 
FROM 
  local_table 
JOIN 
  fed_orders 
ON 
  local_table.foreign_shipname = fed_orders.shipname;