Using Liquibase with MySQL

To test your connection, try running Liquibase with the JDBC driver located in the same directory as Liquibase:

liquibase
--driver=com.mysql.cj.jdbc.Driver
--classpath=mysql-connector-java-5.1.21-bin.jar
--url="jdbc:mysql://<IP OR HOSTNAME>:<PORT>/<SCHEMA NAME>?autoReconnect=true&useSSL=FALSE|TRUE" 
--changeLogFile=db.changelog-1.0.xml
--username=<MYSQL USERNAME>
--password=<MYSQL PASSWORD>generateChangeLog

Note: Formatted SQL changelogs generated by using Liquibase versions previous to 4.2 might cause issues because of the lack of space after a double dash ( -- ).

Tip: To fix those issues, add a space after the double dash. For example: -- liquibase formatted sql instead of --liquibase formatted sql and -- changeset myname:create-table instead of --changeset myname:create-table

Creating New Liquibase projects with MySQL – Windows

The purpose of this document is to guide you through the process of creating a new Liquibase project with MySQL on a Windows machine. In this tutorial, you will generate an example project and follow the instructions to apply and learn concepts associated with creating new Liquibase projects with MySQL.

Prerequisites

• If you have not installed the latest version of Liquibase, go to https://www.liquibase.org/download to install it.
• Ensure the liquibase.bat file's path is set to a location in the PATH System variable.
• Go to https://dev.mysql.com/downloads/connector/j/ and download the jdbc driver jar file for MySQL.
  

Note: Place the jdbc jar driver file in a known directory so you can locate it easily.

Example: C:\Users\Liquibase_Drivers\mysql-connector-java-5.1.48.jar

Tutorial

To create a Liquibase project with MySQL on your Windows machine, begin with the following steps:

• Create a new project folder and name it LiquibaseMySQL.
• In your LiquibaseMySQL folder, create a new text file and name it dbchangelog.xml. changelog files contain a sequence of changesets, each of which make small changes to the structure of your database. To add this change:
• Open the dbchangelog.xml file and update the changelog file with the following code snippet:

<?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"  
    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
    http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.8.xsd">
 </databaseChangeLog>

• In your LiquibaseMySQL folder, create another text file and name it liquibase.properties.
• Edit the liquibase.properties file to add the following properties:

 changeLogFile: C:\\Users\\Administrator\\LiquibaseMySQL\\dbchangelog.xml 
 url: jdbc:mysql://localhost:3306/my_schema
 username: root
 password: password
 driver: org.gjt.mm.mysql.Driver  
 classpath: ../../Liquibase_Drivers/mysql-connector-java-5.1.48.jar

As you are creating this project on Windows OS, you must specify the path with double slashes in the changeLogFile property. Also, use a relative path from your project directory to the driver jdbc jar file location in the classpath property.

Note: If you already have a Liquibase Pro key and want to apply it to your project, add the following property to your liquibase.properties file.

liquibaseProLicenseKey: <paste license key>

• Add a changeset to the changelog. changesets are uniquely identified by author and id attributes. Liquibase attempts to execute each changeset in a transaction that is committed at the end. In the dbchangelog.xml file, add a new department create table changeset as follows:

<?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" 
xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.8.xsd">

<changeSet id="1" author="bob"> 
        <createTable tableName="department">
            <column name="id" type="int">
            <constraints primaryKey="true" nullable="false"/> 
            </column> 
            <column name="name" type="varchar(50)">
            <constraints nullable="false"/>  
            </column>
            <column name="active" type="boolean"
            defaultValueBoolean="true"/> 
        </createTable>
   </changeSet>
</databaseChangeLog>

Note: This changeset is an XML format. The corresponding SQL statement should look like the following:

CREATE TABLE "department"
("id" number (*,0),
"name" VARCHAR2 (50 BYTE),
"active" NUMBER (1, 0) DEFAULT 1
 );

• Open the command prompt and navigate to the LiquibaseMySQL directory.
  Run the following command:

liquibase update

• From a database UI Tool (for example, MySQL Workbench), check your database changes under my_schema. You should see a new department table added to the database. For example:

SELECT * FROM my_schema.department;

ID	NAME	ACTIVE
NULL	NULL	NULL

Also, you should see two more tables:

• DATABASECHANGELOG tracking table – This table keeps a record of all the changesets that were deployed. This way, next time when you deploy again, the changesets in the changelog will be compared with the DATABASECHANGELOG tracking table and only the new changesets that were not found in the DATABASECHANGELOG will be deployed. You will notice that a new row was created in that table with the changeset information we have just deployed. For this example:

ID	AUTHOR	FILENAME	DATEEXECUTED	ORDEREXECUTED	EXECTYPE	MDSUM	…
1	bob	dbchangelog.xml	date&time	1	EXECUTED	checksumvalue	…

• DATABASECHANGELOGLOCK – This table is used internally by Liquibase to manage access to the changelog table during deployment.