Ready to get started?

Learn more about the CData ODBC Driver for MariaDB or download a free trial:

Download Now

Access MariaDB Data as a Remote Oracle Database

Use the Oracle ODBC Gateway and Heterogeneous Services technology to access MariaDB data from your Oracle system.

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 MariaDB to create a database link from MariaDB to Oracle and to query MariaDB data through the SQL*Plus tool. You can also create the database link and execute queries from SQL Developer.

Connect to MariaDB as an ODBC Data Source

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

The Server and Port properties must be set to a MariaDB server. If IntegratedSecurity is set to false, then User and Password must be set to valid user credentials. Optionally, Database can be set to connect to a specific database. If not set, the tables from all databases are reported.


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 MariaDB 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.


If you are installing the CData ODBC Driver for MariaDB 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.


[CData MariaDB Source] Driver = CData ODBC Driver for MariaDB Description = My Description User = myUser Password = myPassword Database = NorthWind Server = myServer Port = 3306

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 MariaDB data just as you would an Oracle database. Set the following properties when working with MariaDB 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-mariadb/lib/cdata.odbc.mariadb.ini in a text editor and set the encoding.


[Driver] DriverManagerEncoding = UTF-8

Configure the ODBC Gateway, Oracle Net, and Oracle Database

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

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


    HS_FDS_CONNECT_INFO = "CData MariaDB 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:


    SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = mymariadbdb) (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:


    SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = mymariadbdb) (ORACLE_HOME = your-oracle-home) (PROGRAM = hsodbc) ) )
  3. Add the connect descriptor below in tnsnames.ora, located in oracle-home-directory/NETWORK/admin:


    mymariadbdb = (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521)) (CONNECT_DATA=(SID=mymariadbdb)) (HS=OK) )
  4. Restart the listener.
  5. Test the configuration with the following command:

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

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

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

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