I've been working with Sequelize on the PairUp project for a little bit now. I've talked about transactions, migrations, and data integrity. However, I didn't quite put together why Sequelize specifically has a unique approach and implementation of certain features like transactions or data validation.

Sequelize provides built-in support for data validation and transactions, through its Model and Transaction objects. Since I have spoken about transactions in a previous post, let's dive into model objects. In Sequelize, Model objects represent tables in the database and define their attributes, associations, and methods for accessing and manipulating data. Model objects are defined using the sequelize.define() method and are typically stored in separate files in a ‘models’ directory.

While there are some comparisons between Sequelize and other popular ORM libraries we can break down the differences between it and another ORM called TypeORM that are worth mentioning.

1. Model definition: In TypeORM, model entities are defined using decorators, whereas in Sequelize, model objects are defined using a JavaScript-based API. This means that defining models in TypeORM involves writing more boilerplate code, whereas Sequelize provides a more concise and flexible syntax.

2. Validation: TypeORM provides built-in support for validation using decorators, whereas Sequelize provides a validation API for defining constraints on model attributes. TypeORM's validation is more powerful and flexible but requires more code to set up and use.

3. Database migrations: TypeORM provides powerful tools for database schema migrations, whereas Sequelize relies on third-party tools like sequelize-cli for database migrations. TypeORM's migration tools make it easier to manage schema changes over time, whereas Sequelize's approach requires more manual intervention.

The Image I have shared in this post shows an example of a model object. In it, we define a User model using the sequelize.define() method with two attributes, name, and email, which are defined as DataTypes.STRING and are marked as required using the allowNull option.

Hopefully, this helps shine a light on some unique attributes Sequelize possesses!

Remember, there’s something special about everyone and everything!

Have a good day. Be well.

WORKING PROJECT PAIRUP

https://github.com/timmyichen/dev-directory

Sequelize:

https://sequelize.org/docs/v6/core-concepts/model-instances/