Liquibase Changelog file

ChangeLog file list all the changes in the Database. This ledger helps Liquibase to understand the current status of the Database and execute changes that need to be applied.

ChangeLog file divides the individual small change into ChangeSet, and each Database operation is stored sequentially in ChangeSet. For example, Database creation is 1 change set and table creation is another ChangeSet.

It is a best practice to add only one Change Type per changeset.

A complex Database schema can be subdivided into multiple individuals ChangeLog files. ChangeLog file allows preconditions, contexts, labels, and many other attributes.

Liquibase allows to pass the ChangeLog file dynamically with --changelog-file argument in the command line (CLI), or else the ChangeLog file can be set as JAVA_OPTS in Environment Variable.

ChangeLog file format

Liquibase supports ChangeLog files in native SQL format or platform-agnostic XML, YAML, or JSON formats. it determines the format by the file extension. ChangeLog can include another ChangeLog file or include All multiple small ChangeLog files from a folder in XML, YAML, or JSON formats only SQL doesn't support file inclusion.

changelog.mysql.sql

-- liquibase formatted sql

-- changeset wesome:1692352309572-1
CREATE TABLE apple (apple_id BIGINT NOT NULL, apple_name VARCHAR(255) NULL, CONSTRAINT PK_APPLE PRIMARY KEY (apple_id));

changelog.mysql.yaml

databaseChangeLog:
  - changeSet:
      id: 1692352255676-1
      author: wesome (generated)
      changes:
        - createTable:
            columns:
              - column:
                  constraints:
                    nullable: false
                    primaryKey: true
                  name: apple_id
                  type: BIGINT
              - column:
                  name: apple_name
                  type: VARCHAR(255)
            tableName: apple

changelog.mysql.json

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "1692352264594-1",
        "author": "wesome (generated)",
        "changes": [
          {
            "createTable": {
              "columns": [
                {
                  "column": {
                    "constraints": {
                      "nullable": false,
                      "primaryKey": true
                    },
                    "name": "apple_id",
                    "type": "BIGINT"
                  }
                },
                {
                  "column": {
                    "name": "apple_name",
                    "type": "VARCHAR(255)"
                  }
                }
              ],
              "tableName": "apple"
            }
          }
        ]
      }
    }
  ]
}

changelog.mysql.xml

<?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 (generated)" id="1692352246983-1">
        <createTable tableName="apple">
            <column name="apple_id" type="BIGINT">
                <constraints nullable="false" primaryKey="true"/>
            </column>
            <column name="apple_name" type="VARCHAR(255)"/>
        </createTable>
    </changeSet>
</databaseChangeLog>

Liquibase supports the use of multiple different changelog file formats at a time.

The ChangeLog file name is stored in the liquibase.properties file. Liquibase migrator detects the ChangeLog file format from the file extension.

It checks for global preconditions first, then includes all ChangeLog files specified with the include tag. run each change set and store the executed changes in DATABASECHANGELOG table.