Скачать или смотреть How to Use a Single Transaction with Multiple Queries in NestJS-TypeORM

Learn how to effectively manage database transactions across multiple repositories in NestJS using TypeORM, similar to Sequelize.
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Managing Transactions in NestJS with TypeORM: A Comprehensive Guide

When building applications with a NestJS framework and using TypeORM as your ORM, one common challenge you might face is managing database transactions, especially when working with multiple queries across different repositories. This can be particularly tricky if you are transitioning from another ORM like Sequelize, where transaction management seems more straightforward.

In this guide, we will explore how to efficiently use a single transaction involving multiple queries with NestJS and TypeORM, enabling you to maintain data consistency throughout your operations.

Understanding the Challenge

In your NestJS application, suppose you have two entity services that interact with different database tables:

EntityOneService: Manages operations related to EntityOne

EntityTwoService: Manages operations related to EntityTwo

Here's what the basic service classes look like:

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

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

You want to execute queries against both repositories inside a single transaction to ensure that either all operations succeed or none at all. However, simply calling the find() methods from both services does not achieve this transactional integrity.

Using Transaction with TypeORM

To enable transactions in TypeORM, you'll need to leverage the EntityManager, which allows you to execute multiple operations in a transaction scope. Here’s a step-by-step guide:

Step 1: Create a Transaction

You can use the connection's transaction method to start a transaction. Here's how you can structure your operations:

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

Step 2: Utilizing withRepository

A powerful feature provided by TypeORM's transaction management is the withRepository method. This allows you to specify which repository you want to use within the context of your transaction.

Step 3: Implementing in BaseService

To make your BaseServices compatible with transaction management, you will need to adjust the methods to accept the EntityManager as a parameter. Here’s an example:

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

Now, every time you call findAll, you can pass the EntityManager to maintain the transaction context.

Complete Transaction Implementation

With all components working together, your transaction management might look like this:

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

Conclusion

By utilizing TypeORM's EntityManager and its withRepository method, you can conveniently manage your database operations within a single transaction. This bridges the gap for developers moving from Sequelize to TypeORM, ensuring that your application maintains data integrity while executing multiple queries.

If you would like an example implementation, feel free to reach out, and I can share a repository with you.

Final Thoughts

Managing transactions in NestJS with TypeORM may initially seem daunting, but with an understanding of the EntityManager and repository patterns, you can effectively control your database operations while ensuring that they run smoothly and cohesively. Happy coding!