Generate your changelog from an existing database

You can use the following example code. Be sure to:

• Navigate to your Liquibase project folder in the CLI.

• Set your_changelog_file_name to a name for the changelog file that will be generated, such as dbchangelog.

• Set your_file_extension to the format you'd like to use, such as dbchangelog.xml. Liquibase supports .sql, .yaml, .json, and .xml formats.

Note: After you create a Liquibase project using liquibase init project, Liquibase generates a standard project structure, including a file named example-changelog.sql. This file is only a sample, once you've generated your changelogs, you can delete it to avoid confusion.

By default, generate-changelog produces a single changelog file. In Liquibase Secure 5.2 and later, you can use --object-changelogs=all to automatically split the output into separate files organized by object type:

Liquibase creates a folder for each object type and generates a master changelog that references them all. Changesets are ordered so the changelog deploys without manual reordering.

Once you have your changelog file, populate the DATABASECHANGELOG tracking table with the changesets from this changelog.

Liquibase keeps track of your already deployed changes with the help of its DATABASECHANGELOG tracking table.

To create this table for the first time, use the changelog-sync command. The changelog-sync command will populate the DATABASECHANGELOG table with the changesets metadata as if you have been using Liquibase all along.

This command updates the tracking table so Liquibase knows your database is up to date with the changelog. It won’t make any schema changes.