DDL with MariaDB Connector/R2DBC (Native API)

Overview

Java developers can use MariaDB Connector/R2DBC to connect to MariaDB database products using the Reactive Relational Database Connectivity (R2DBC) API. R2DBC operations are non-blocking, which makes R2DBC more scalable than Java's standard JDBC API.

DDL (Data Definition Language) refers to all SQL-schema statements in the SQL standard (ISO/IEC 9075-2:2016).

Some examples of DDL include ALTER TABLE, CREATE TABLE, DROP TABLE, CREATE DATABASE, and TRUNCATE.

DDL Operations

With R2DBC, DDL statements are performed with the following classes:

Class	Description
io.r2dbc.spi.Statement	Creates a statement to execute on the server.
io.r2dbc.spi.Result	Contains the result-set from the server.

Code Example: ALTER TABLE

ALTER TABLE is a DDL (Data Definition Language) operation that makes changes to an existing table. The following example changes the example table created in Setup for Examples.

//Module Imports import org.mariadb.r2dbc.MariadbConnectionConfiguration; import org.mariadb.r2dbc.MariadbConnectionFactory; import io.r2dbc.spi.Connection; import reactor.core.publisher.Mono;  //Main Application Class public class App {  // Connection Configuration  private static MariadbConnectionConfiguration conf;  private static MariadbConnectionFactory connFactory;  private static Connection conn;   // Main Process  public static void main(String[] args) {  // Initialize Connection Factory  initConnectionFactory();   // Alter Contacts Table  alterContactsTable();  }   public static void initConnectionFactory() {  try {  // Configure the Connection  conf = MariadbConnectionConfiguration.builder()  .host("192.0.2.1").port(3306)  .username("db_user").password("db_user_password")  .database("test").build();   // Instantiate a Connection Factory  connFactory = new MariadbConnectionFactory(conf);  }  catch (java.lang.IllegalArgumentException e) {  System.err.println("Issue encountered while creating connection factory");  e.printStackTrace();  }  }   public static void alterContactsTable() {  try {  //Initialize a Connection  conn = connFactory.create().block();   //Create and run a Statement  Mono.from(  conn.createStatement("ALTER TABLE test.contact CHANGE COLUMN first_name f_name VARCHAR(25)").execute()  ).subscribe();  }  // Catch Exception  catch (java.lang.IllegalArgumentException e) {  System.err.println("Issue altering contact table");  e.printStackTrace();  } finally {  // Close Connection  conn.close();  }  } }

Confirm the table was properly altered by using MariaDB Client to execute a DESC statement on the same table:

DESC test.contact;

+-----------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------+-------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | f_name | varchar(25) | YES | | NULL | | | last_name | varchar(25) | YES | | NULL | | | email | varchar(25) | YES | | NULL | | +-----------+-------------+------+-----+---------+----------------+

Code Example: TRUNCATE TABLE

The following example shows how to truncate the example table created in Setup for Examples.

TRUNCATE is a DDL (Data Definition Language) operation that deletes all data from an existing table and resets the AUTO_INCREMENT column counter to 0:

//Module Imports import org.mariadb.r2dbc.MariadbConnectionConfiguration; import org.mariadb.r2dbc.MariadbConnectionFactory; import io.r2dbc.spi.Connection; import reactor.core.publisher.Mono;  //Main Application Class public class App {   // Connection Configuration  private static MariadbConnectionConfiguration conf;  private static MariadbConnectionFactory connFactory;  private static Connection conn;   // Main Process  public static void main(String[] args) {  //Initialize Connection Factory  initConnectionFactory();   // Truncate table  truncateTable();  }   public static void initConnectionFactory() {  try {  // Configure the Connection  conf = MariadbConnectionConfiguration.builder()  .host("192.0.2.1").port(3306)  .username("db_user").password("db_user_password")  .database("test").build();   // Instantiate a Connection Factory  connFactory = new MariadbConnectionFactory(conf);  }  catch (java.lang.IllegalArgumentException e) {  System.err.println("Issue encountered while getting connection");  e.printStackTrace();  } finally {  // ...  }  }   public static void truncateTable() {  try {   //Initialize a Connection  conn = connFactory.create().block();   // Initialize and run a Statement   Mono.from(  conn.createStatement("TRUNCATE test.contact").execute()  ).subscribe();  }  // Catch Exception  catch (java.lang.IllegalArgumentException e) {  System.err.println("Issue truncating contact table");  e.printStackTrace();  } finally {  // Close Connection  conn.close();  }  } }

Confirm the table was properly truncated by using MariaDB Client to execute a SELECT statement on the same table:

SELECT * FROM test.contact;

Empty set (0.000 sec)

_{This page is: Copyright © 2025 MariaDB. All rights reserved.}