What is Liquibase?
Liquibase is an open source library to track database changes.
What does that mean? We all have worked in projects where the typical database change management process was to write DDL, DML scripts in sql files which were source controlled and database changes were executed by self or by some other dedicated team. But there wasn’t really a nice way to define sequence of these changes, it was followed as best practice in the project. We always had to write sql for rollbacks as well and migration to other database was a painful task.
Liquibase tries to address all these issues in an elegant way. Liquibase scripts are typically written in xml format (may be because xml is more readable), though other formats like json and yaml are also supported. Database changes are defined in change log files as small change sets which are uniquely identified by change set name and author. Sequence is defined in master change log file. Rollbacks are handled in most of the cases by Liquibase itself. And since these scripts are database agnostic, migrations to other databases are relatively smooth. As of now, Liquibase supports most of the popular database including MySQL, Oracle, DB2 and PostgreSQL.
