Access Lakebase Data as a Remote Oracle Database

The Oracle Database Gateway for ODBC and Heterogeneous Services technology enable you to connect to ODBC data sources as remote Oracle databases. This article shows how to use the CData ODBC Driver for Lakebase to create a database link from Lakebase to Oracle and to query Lakebase data through the SQL*Plus tool. You can also create the database link and execute queries from SQL Developer.

Connect to Lakebase as an ODBC Data Source

Information for connecting to Lakebase follows, along with different instructions for configuring a DSN in Windows and Linux environments.

• 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.

Windows

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

Note: If you need to modify the DSN or create other Lakebase DSNs, you must use a system DSN and the bitness of the DSN must match your Oracle system. You can access and create 32-bit DSNs on a 64-bit system by opening the 32-bit ODBC Data Source Administrator from C:\Windows\SysWOW64\odbcad32.exe.

Linux

If you are installing the CData ODBC Driver for Lakebase in a Linux environment, the driver installation predefines a system DSN. You can modify the DSN by editing the system data sources file (/etc/odbc.ini) and defining the required connection properties.

/etc/odbc.ini

[CData Lakebase Source]
Driver = CData ODBC Driver for Lakebase
Description = My Description
DatabricksInstance = lakebase
Server = 127.0.0.1
Port = 5432
Database = my_database
InitiateOAuth = GETANDREFRESH

For specific information on using these configuration files, please refer to the help documentation (installed and found online).

Set Connection Properties for Compatibility with Oracle

The driver provides several connection properties that streamline accessing Lakebase data just as you would an Oracle database. Set the following properties when working with Lakebase data in SQL*Plus and SQL Developer. For compatibility with Oracle, you will need to set the following connection properties, in addition to authentication and other required connection properties.

• MapToWVarchar=False

  Set this property to map string data types to SQL_VARCHAR instead of SQL_WVARCHAR. By default, the driver uses SQL_WVARCHAR to accommodate various international character sets. You can use this property to avoid the ORA-28528 Heterogeneous Services data type conversion error when the Unicode type is returned.

• MaximumColumnSize=4000

  Set this property to restrict the maximum column size to 4000 characters.

• IncludeDualTable=True

  Set this property to mock the Oracle DUAL table. SQL Developer uses this table to test the connection.

Linux Configuration

In Linux environments, Oracle uses UTF-8 to communicate with the unixODBC Driver manager, whereas the default driver encoding is UTF-16. To resolve this, open the file /opt/cdata/cdata-driver-for-lakebase/lib/cdata.odbc.lakebase.ini in a text editor and set the encoding.

cdata.odbc.lakebase.ini

[Driver]
DriverManagerEncoding = UTF-8

Configure the ODBC Gateway, Oracle Net, and Oracle Database

Follow the procedure below to set up an ODBC gateway to Lakebase data that enables you to query live Lakebase data as an Oracle database.

1. Create the file initmylakebasedb.ora in the folder oracle-home-directory/hs/admin and add the following setting:

   initmylakebasedb.ora

   HS_FDS_CONNECT_INFO = "CData Lakebase Sys"

2. Add an entry to the listener.ora file. This file is located in oracle-home-directory/NETWORK/admin.

   If you are using the Database Gateway for ODBC, your listener.ora needs to have a SID_LIST_LISTENER entry that resembles the following:

   listener.ora

   SID_LIST_LISTENER =
     (SID_LIST =
       (SID_DESC =
         (SID_NAME = mylakebasedb)
         (ORACLE_HOME = your-oracle-home)
         (PROGRAM = dg4odbc)
       )
     )
   

   If you are using Heterogeneous Services, your listener.ora needs to have a SID_LIST_LISTENER entry that resembles the following:

   listener.ora

   SID_LIST_LISTENER =
     (SID_LIST =
       (SID_DESC =
         (SID_NAME = mylakebasedb)
         (ORACLE_HOME = your-oracle-home)
         (PROGRAM = hsodbc)
       )
     )
   

3. Add the connect descriptor below in tnsnames.ora, located in oracle-home-directory/NETWORK/admin:

   tnsnames.ora

   mylakebasedb  =
     (DESCRIPTION=
       (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))
       (CONNECT_DATA=(SID=mylakebasedb))
       (HS=OK)
     ) 
   

4. Restart the listener.

5. Test the configuration with the following command:

   tnsping mylakebasedb

6. Open SQL*Plus and create the database link with the command below:

   CREATE DATABASE LINK mylakebasedb CONNECT TO "user" IDENTIFIED BY "password" USING 'mylakebasedb';

You can now execute queries in SQL*Plus like the one below (note the double quotation marks around the table name):

SELECT * from "Orders"@mylakebasedb WHERE ShipCountry = 'USA';