Flyway vs Sequelize: What are the differences?

Key Differences between Flyway and Sequelize

Flyway and Sequelize are both popular database migration tools, but they have some key differences that are worth considering when choosing the appropriate tool for your project.

1. Language and Framework Support: Flyway is a database migration tool primarily designed for SQL-based databases, while Sequelize is an Object-Relational Mapping (ORM) tool specifically developed for Node.js and supports various databases such as MySQL, PostgreSQL, SQLite, and Microsoft SQL Server. This difference in language and framework support makes Flyway a better choice for projects that heavily rely on SQL scripts, while Sequelize is more suitable for Node.js projects that require an ORM.

2. Migration Workflow: Flyway follows a declarative approach to database migrations, where developers write SQL scripts that are executed in the order specified. On the other hand, Sequelize follows an imperative approach, where developers use JavaScript to define the migrations and their order of execution. The declarative approach of Flyway provides a simple and intuitive way to manage migrations, while Sequelize's imperative approach allows for more flexibility in defining complex migration workflows.

3. Versioning and Tracking: Flyway uses a version-based approach for tracking and managing migrations. Each migration script is associated with a version number, and Flyway automatically applies new migrations based on the version numbers. In contrast, Sequelize uses a timestamp-based approach, where each migration is associated with a timestamp that determines the order of execution. This difference in versioning and tracking mechanisms allows Flyway to easily handle sequential migrations, while Sequelize offers more granular control over the order of execution.

4. Migration Scripting: Flyway uses plain SQL scripts to define database migrations. These scripts can be written using any SQL dialect supported by the targeted database. Conversely, Sequelize provides a JavaScript-based migration API, allowing developers to write migrations using JavaScript code that can leverage the full power of the language. This difference in scripting languages gives Sequelize an advantage in terms of programmability and customization options.

5. Migration Rollbacks: Flyway allows for easy rollbacks by supporting backward migrations that undo the changes made by a specific migration script. This can be achieved by simply applying a rollback script associated with the original migration. In comparison, Sequelize does not provide built-in support for rollback operations. Instead, developers have to manually define and execute the reverse migrations to undo the changes made by previous migrations.

6. Community and Ecosystem: Flyway and Sequelize have active and growing communities, which provide support, documentation, and extensions/plugins for these tools. However, Sequelize benefits from the wider Node.js ecosystem, which offers additional libraries, utilities, and integrations that can enhance its functionality and make the development process more efficient.

In summary, Flyway is a SQL-based database migration tool suitable for projects heavily relying on SQL scripts, while Sequelize is an ORM tool specifically designed for Node.js projects. Flyway follows a declarative approach and offers version-based migration tracking, while Sequelize follows an imperative approach with timestamp-based migration tracking. Flyway uses SQL scripts, while Sequelize provides a JavaScript-based migration API. Flyway supports easy rollbacks, while Sequelize requires manual definition and execution of reverse migrations. The wider Node.js ecosystem further enhances the functionality of Sequelize.