Скачать или смотреть How to Create Triggers in Node.js MySQL2 Without Using Sequelize

Learn how to create database triggers in Node.js using the MySQL2 library without relying on Sequelize. This guide offers step-by-step instructions and clear examples.
---
This video is based on the question https://stackoverflow.com/q/73122253/ asked by the user 'Jagadish Shrestha' ( https://stackoverflow.com/u/17437404/ ) and on the answer https://stackoverflow.com/a/73125533/ provided by the user 'Jagadish Shrestha' ( https://stackoverflow.com/u/17437404/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: create trigger in nodejs mysql2 without using sequalize

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Creating Triggers in Node.js with MySQL2: A Step-by-Step Guide

In database management, a trigger is a set of instructions that automatically executes in response to a specific event on a particular table or view. In this guide, we will explore how to create triggers in a Node.js application using the MySQL2 library, without the need for an ORM like Sequelize. If you've been facing challenges with delimiter issues while trying to create triggers, this guide will walk you through an alternative approach.

The Problem: Creating Triggers Without Sequelize

As you may know, the traditional way to create triggers in MySQL involves using a delimiter to separate multiple SQL statements. However, the MySQL2 library used in Node.js doesn't support this feature directly. Many developers encounter issues when trying to define triggers, as they may have come from environments like MySQL Workbench, where delimiters are easily managed.

Why the Delimiter Issue Occurs

The delimiter is crucial because it signifies the end of a statement in SQL. In scripting environments, like that provided by Node.js, there is no built-in support for handling delimiters. Therefore, we cannot simply input a multi-line SQL trigger script in the same way we do in other environments.

The Solution: Using String Concatenation

We can tackle the delimiter issue by using string concatenation in JavaScript. This allows us to construct the SQL trigger statement from separate lines, and then execute it as a single string. Here's a breakdown of how to do this effectively.

Step-by-Step Instructions

Construct the Trigger Statement

Instead of using a delimiter, we can simply concatenate strings using the + operator. Here’s how you can create a trigger that records updates to a supplier table:

[[See Video to Reveal this Text or Code Snippet]]

Execute the Query

After constructing the SQL string, you can use the db.query method to execute it. Here’s how the complete function looks:

[[See Video to Reveal this Text or Code Snippet]]

Full Code Example

Here’s a complete snippet for a function that creates a trigger in your database:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Creating triggers in Node.js using the MySQL2 library can be seamlessly accomplished by using string concatenation to bypass delimiter issues. This approach provides a straightforward way to handle database actions without the dependencies of an ORM like Sequelize. By following the steps outlined in this guide, you'll be able to effectively implement triggers in your applications, leading to better data integrity and responsiveness.

If you found this guide helpful, consider sharing it with your fellow developers who may also be navigating similar challenges. Happy coding!