If you are building an application with Spring Boot, handling the database changes becomes a nightmare over time. The more changes you add, the more changes you have to maintain for your database. Liquibase is the best solution out there. In this post, we will show how to handle database changes using liquibase.

What is Liquibase?

Liquibase is an open-source library to track, manage, and apply database changes. Liquibase tracks the changes to database through an XML configuration where a developer will usually add changesets.

Each changeset will have an id and author attributes. Liquibase uses a changelog to track the database changes. Every changeset you add, that will get added in the changelog. Changelog is a ledger of all the changes you are doing to database.

How does Liquibase work?

To track database changes, you will write an XML file that is platform-independent. This XML file will be used on the command line to translate into scripts for your database engine.

We can also use a maven or Gradle plugin to include database changes in the build configuration.

Liquibase uses its own tables to track changes. Those tables will be part of the schema you are building for consistency purposes. It records the hash of each changeset.

How to write a changeset?

Previously, I mentioned you can write a changeset using XML. But liquibase also offers the support for JSON or YAML.

As part of this post, I will show how I add a changeset and generate scripts for the database.

Create an XML changelog file db.changelog-master.xml for our database under folder src\main\resources\db. Usually, if you start using liquibase from the start of the project, you will create an initial changelog file that will generate initial scripts. You can track every change after that through a change set.

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