Sequel vs Sequelize: What are the differences?

Introduction

Sequel and Sequelize are both popular Object Relational Mapping (ORM) libraries used in web development. While they serve the same purpose of mapping database tables to object-oriented models, they have some key differences that set them apart.

1. Database Compatibility: Sequel is a versatile ORM that supports a wide range of database systems, including relational databases like MySQL, PostgreSQL, and SQLite, as well as NoSQL databases like MongoDB. On the other hand, Sequelize is primarily designed for relational databases, with support for MySQL, PostgreSQL, SQLite, and SQL Server.

2. Language Support: Sequel is written in Ruby and provides a Ruby-like API for working with databases. It is commonly used in Ruby on Rails projects. On the contrary, Sequelize is written in JavaScript and primarily used with Node.js. It integrates seamlessly with Express.js and other Node.js frameworks.

3. Promises vs. Callbacks: Sequel primarily uses callbacks for asynchronous operations. On the other hand, Sequelize uses Promises, making it easier to handle asynchronous operations using modern JavaScript syntax. This can lead to cleaner and more readable code.

4. Table Creation: In Sequel, tables are typically defined using a DSL (Domain Specific Language) in the Ruby language. Developers have fine-grained control over the structure and behavior of tables. Sequelize, on the other hand, uses model definitions written in JavaScript, which are then used to automatically generate the corresponding database tables. This provides a more concise and easy-to-use approach for table creation.

5. Association Handling: Sequel provides a straightforward way to define associations between model classes, such as one-to-one, one-to-many, and many-to-many relationships. Sequelize, on the other hand, handles associations using special functions and decorators. This allows for more flexibility and provides additional features like eager loading.

6. Maturity and Community: Sequel has been around since 2007 and is a mature and well-established ORM with a large community of users. It has accumulated a wealth of documentation and resources. Sequelize, on the other hand, was released in 2010 and has gained popularity primarily in the Node.js and JavaScript communities. While it may not have the same level of maturity as Sequel, it has an active community and frequent updates.

In Summary, Sequel provides wide database compatibility, uses Ruby-like API, primarily uses callbacks, offers fine-grained table creation control, and has a more mature community. Sequelize, on the other hand, focuses on relational databases, uses JavaScript, primarily uses Promises, offers automatic table generation, provides rich association handling, and has gained popularity in the Node.js and JavaScript communities.