Methodologies

Flyway:

• Migration Scripts: Flyway primarily uses plain SQL scripts to manage database migrations, though it also supports Java-based migrations. Each migration is a versioned SQL file that contains the changes you want to apply.
• Version Control: Migrations are applied sequentially based on their version number. Flyway keeps track of which migrations have been applied using a dedicated schema history table in the database.
• Convention Over Configuration: Flyway relies heavily on convention. For example, the naming of migration files (like V1__Create_users_table.sql) follows a specific pattern that Flyway expects.
• Simple Rollbacks: Flyway supports rollbacks, but it’s relatively simplistic. You can either use a separate undo migration script (manually written) or rely on rolling forward to fix issues.
• CI/CD Integration: Flyway is easy to integrate into CI/CD pipelines due to its straightforward and script-based approach.

Liquibase:

• ChangeSets: Liquibase uses the concept of "ChangeSets," which are units of change written in XML, YAML, JSON, or SQL. These ChangeSets describe the desired state of the database and can include more complex operations than Flyway.
• ChangeLog File: Liquibase uses a "ChangeLog" file to list the ChangeSets that should be applied. This file can be hierarchical, allowing for complex dependency management between different migrations.
• Rollback Scripts: Liquibase has more sophisticated rollback capabilities. Rollbacks can be defined in the same ChangeSet, allowing you to undo changes by simply running a command. Rollbacks can also be automated based on the ChangeSet.
• Database-Agnostic: Liquibase's ability to use abstract definitions means it can generate database-specific SQL, making it more database-agnostic than Flyway, which directly uses SQL scripts.
• Complexity Handling: Liquibase is well-suited for complex database environments with branching, merging, and other advanced scenarios.

Features

Flyway:

• Ease of Use: Simple and easy to set up, especially for teams that prefer SQL scripting.
• Lightweight: Flyway is lightweight, with a focus on convention over configuration.
• Speed: Faster execution due to its simple and direct approach.
• Tooling: Integrates well with many build tools like Maven, Gradle, and Ant, and is easy to integrate into CI/CD pipelines.
• Community Support: Has a strong community and good documentation, making it easy to find support and resources.