Book Image

Supercharging Node.js Applications with Sequelize

By : Daniel Durante
4 (1)
Book Image

Supercharging Node.js Applications with Sequelize

4 (1)
By: Daniel Durante

Overview of this book

Continuous changes in business requirements can make it difficult for programmers to organize business logic into database models, which turns out to be an expensive operation as changes to the database may result in errors and incongruity within applications. Supercharging Node.js Applications with Sequelize helps you get to grips with Sequelize, a reliable ORM that enables you to alleviate these issues in your database and applications. With Sequelize, you'll no longer need to store information in flat files or memory. This book takes a hands-on approach to implementation and associated methodologies for your database that will have you up and running in no time. You'll learn how to configure Sequelize for your Node.js application properly, develop a better sense of understanding of how this ORM works, and find out how to manage your database from Node.js using Sequelize. Finally, you'll be able to use Sequelize as the database driver for building your application from scratch. By the end of this Node.js book, you'll be able to configure, build, store, retrieve, validate, and associate your data from a database to a Node.js application.
Table of Contents (16 chapters)
1
Part 1 – Installation, Configuration, and the Basics
4
Part 2 – Validating, Customizing, and Associating Your Data
10
Part 3 – Advanced Queries, Using Adapters, and Logging Queries

Using lifecycle events with associations and transactions

As the default behavior, Sequelize will execute lifecycle events without associating a transaction with any database queries that are invoked within the lifecycle’s scope. However, sometimes our project requires transactions to be used within lifecycle events, such as an accountant’s ledger or creating log entries. Sequelize offers a transaction parameter when calling certain methods, such as update, create, destroy, and findAll, that will allow us to use a transaction that was defined outside of the lifecycle’s scope to be used within the lifecycle itself.

Note

When calling beforeDestroy and afterDestroy on a model, Sequelize will intentionally skip destroying any associations with that model unless the onDelete parameter is set to CASCADE and the hooks parameter is set to true. This is due to Sequelize needing to explicitly delete each association row by row, which could cause congestion if we are...