Liquibase Change Types dropDefaultValue

Liquibase supports default value with addDefaultValue Change Type to add a default value parameter to alter the existing definition for the specified column in a table.

Sometimes requirement is to drop some Default Value of the columns from the existing tables. Liquibase provides dropDefaultValue Change Type to drop existing defalt value.

Create Default Value

<?xml version="1.1" encoding="UTF-8" standalone="no"?>
<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog" xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext" xmlns:pro="http://www.liquibase.org/xml/ns/pro" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="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 http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
	<changeSet author="wesome" id="1692599548266-1">
		<createTable catalogName="appledb" tableName="apple">
			<column name="apple_id" type="BIGINT">
			</column>
			<column name="apple_name" type="VARCHAR(255)" />
		</createTable>
	</changeSet>
	<changeSet author="wesome" id="1692599548266-2">
		<addDefaultValue catalogName="appledb" columnDataType="varchar(20)" columnName="apple_name" defaultValue="Fuji" schemaName="appledb" tableName="apple" />
	</changeSet>
	<changeSet author="wesome" id="1692701200879-3">
		<insert catalogName="appledb" tableName="apple">
			<column name="apple_id" valueDate="1" />
		</insert>
	</changeSet>
</databaseChangeLog>

liquibase.properties (update changeLog File file format with SQL, XML, YAML, JSON as per changelog.mysql.)

changeLogFile=changelog.mysql.xml
liquibase.command.url:jdbc:mysql://localhost:3306/appleDb?createDatabaseIfNotExist=true&autoReconnect=true&useSSL=false&allowPublicKeyRetrieval=true
liquibase.command.username : root
liquibase.command.password : rootroot

Run command liquibase update

Liquibase adds the apple_id value as provided in the changeset and the default value of the apple_name column, the same can be verified by running the query

SELECT * FROM appleDb.apple;

 

Drop Default Value

<?xml version="1.1" encoding="UTF-8" standalone="no"?>
<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog" xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext" xmlns:pro="http://www.liquibase.org/xml/ns/pro" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="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 http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
	<changeSet author="wesome" id="1692701200879-4">
		<dropDefaultValue catalogName="appledb" columnDataType="VARCHAR(255)" columnName="apple_name" schemaName="appledb" tableName="apple" />
	</changeSet>
</databaseChangeLog>

liquibase.properties (update changeLog File file format with SQL, XML, YAML, JSON as per changelog.mysql.)

changeLogFile=changelog.mysql.xml
liquibase.command.url:jdbc:mysql://localhost:3306/appleDb?createDatabaseIfNotExist=true&autoReconnect=true&useSSL=false&allowPublicKeyRetrieval=true
liquibase.command.username : root
liquibase.command.password : rootroot

Run command liquibase update

default value in the table definition can be verified by running the query

desc appleDb.apple;