Getting Started with Liquibase and Ant

Apache Ant is a Java library and command-line build tool for Java applications. Liquibase has a set of Ant tasks to automate your database changes at build time.

Note: Liquibase Ant tasks are implemented on the <database> type. For more information about the attributes you can configure for the <database> type, see Ant.

To use Liquibase with Ant:

Ensure you have installed Ant. To verify that Ant is installed, run ant -version at the command prompt. You will get the output that looks like Apache Ant(TM) version 1.10.11 compiled on July 10 2021. Liquibase Ant tasks require Ant 1.7.1 or later versions.
Create a Liquibase project directory to store all Liquibase and Ant files.
Create an Ant build file called build.xml to specify your configuration settings with tasks, targets, and dependencies. The build.xml file also lets you define the needed Liquibase properties. See the example of the build.xml example with a basic configuration.
Include Liquibase in your Ant classpath and load it by adding the <taskdef> task in the build.xml file:

<project basedir="the/runtime/location/of/Ant" name="example" xmlns:liquibase="antlib:liquibase.integration.ant">
     <taskdef resource="liquibase/integration/ant/antlib.xml" uri="antlib:liquibase.integration.ant">
     <classpath path="the/path/to/the/liquibase.jar;the/path/to/the/driver.jar" />
     </taskdef>
</project>

Tip: You can put the Liquibase JAR in your ANT_HOME/lib folder.

Create a text file called changelog.sql in your Liquibase project directory. Liquibase also supports the .xml, .yaml, or .json changelog formats.
Add changesets to your changelog file. Use the following examples depending on the format of the changelog you created:

XML example:

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
    xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext"
    xmlns:pro="http://www.liquibase.org/xml/ns/pro"
    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd
        http://www.liquibase.org/xml/ns/pro http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd">
    <changeSet id="1" author="Liquibase">
    <createTable tableName="test_table">
           <column name="test_id" type="int">
                 <constraints primaryKey="true"/>
           </column>
           <column name="test_column" type="varchar"/>
    </createTable>
    </changeSet>
</databaseChangeLog>

SQL example:

-- liquibase formatted sql

-- changeset liquibase:1
CREATE TABLE test_table (test_id INT, test_column VARCHAR, PRIMARY KEY (test_id))

YAML example:

databaseChangeLog:
- changeSet:
    id: 1
    author: Liquibase
    changes:
    - createTable:
        columns:
        - column:
            name: test_column
            type: INT
            constraints:  
                primaryKey:  true  
                nullable:  false  
                tableName: test_table

JSON example:

{ 
  "databaseChangeLog": [
  {
    "changeSet": {
      "id": "1",
      "author": "Liquibase",
      "changes": [
        {
          "createTable": {
            "columns": [
            {
              "column": 
              {
                "name": "test_column",
                "type": "INT",
                "constraints": 
              {
                "primaryKey": true,
                "nullable": false
                }
                }
              }]
            ,
            "tableName": "test_table"
          }
        }]
      }
    }]
  }

Execute the updateDatabase task by including the values in your Ant build.xml file:

<target name="updateDatabase" depends="prepare">
    <liquibase:updateDatabase changeLogFile="com/example/changelog.sql">
    <liquibase:database driver="org.postgresql.Driver" 
        url="${db.url}" 
        user="${db.user}" 
        password="${db.pass}"/>
    </liquibase:updateDatabase>
</target>

Run the following in the CLI to implement the task and update your database:

ant -f build.xml updateDatabase

After your first update, you will see a new table along with the DATABASECHANGELOG table and DATABASECHANGELOGLOCK table added to the database.

build.xml example:

<project name="liquibase-test" basedir="." xmlns:liquibase="antlib:liquibase.integration.ant">
<!-- The "prepare" target configures the classpath and properties Liquibase will use during task execution.-->
<!-- Liquibase targets must include a "depends" attribute to ensure the prepare target executes before the Liquibase task.-->
    <target name="prepare">

        <taskdef resource="liquibase/integration/ant/antlib.xml" uri="antlib:liquibase.integration.ant">
               <classpath path="lib\liquibase.jar;lib\postgresql-42.2.18.jar"/>
        </taskdef>

<!-- set global properties for Liquibase Tasks -->
<!-- Liquibase properties can be referenced using a "${}" string replacement within a liquibase.database change.-->
        <property name="db.url" value="jdbc:postgresql://localhost:8080/example"/>
        <property name="db.user" value="user"/>
        <property name="db.pass" value="password"/>
        <property name="db.driver" value="org.postgresql.Driver"/>
        <!-- Alternatively, a database instance can be created and referenced with databaseref in a Liquibase task.-->
        <liquibase:database id="my-database" url="${db.url}" user="${db.user}" password="${db.pass}" driver="org.postgresql.Driver"/>
    </target>

<!-- Liquibase Tasks -->
    <!-- The updateDatabase target shows using the individual database connection properties.-->
        <target name="updateDatabase" depends="prepare">
              <liquibase:updateDatabase  changeLogFile="com/example/changelog.sql">
              <liquibase:database driver="${db.driver}" url="${db.url}"  user="${db.user}"  password="${db.pass}"/>
        </liquibase:updateDatabase>
    </target>
</project>

Getting Started with Liquibase and Ant

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