Скачать или смотреть Inserting Data in PostgreSQL with Relation: A Guide for TypeORM and NestJS Users

Learn how to efficiently insert related data in PostgreSQL using TypeORM and NestJS. This guide offers a step-by-step approach to managing entity relationships correctly.
---
This video is based on the question https://stackoverflow.com/q/65967969/ asked by the user 'Asking' ( https://stackoverflow.com/u/12540500/ ) and on the answer https://stackoverflow.com/a/65994568/ provided by the user 'hp10' ( https://stackoverflow.com/u/5370109/ ) 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: Insert data in database depending by relation

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.
---
Inserting Data in PostgreSQL with Relation: A Guide for TypeORM and NestJS Users

In the world of web development, managing databases efficiently is crucial, especially when you are dealing with entity relationships. If you're using TypeORM with NestJS to manage a PostgreSQL database, you might encounter challenges when trying to insert related data. In this post, we will delve into a specific problem and provide a clear solution to help you manage your data relationships seamlessly.

The Problem: Inserting Related Data

When working with entities in TypeORM, such as a Cars entity that has a one-to-many relationship with CarsColors, you might find yourself in a situation where you want to insert a new color for a specific car based on its carId. For instance:

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

The above code attempts to insert a new color for a car identified by carId, but unfortunately, the new entry in the CarsColors table ends up with a carId of null. This occurs because the where clause does not apply to the insert operation, leaving you with references that don’t connect properly.

The Solution: Direct Insertion into CarsColors

The solution here is simple and efficient: instead of trying to filter the insert operation by carId, you should directly insert the new color into the CarsColors entity while specifying the carId. Here's how you can do that clearly:

Step-by-Step Code Example

Establish the Database Connection: Ensure that your TypeORM connection is established before performing any queries.

Insert Color with carId: Use the following code snippet to insert the new color directly into the CarsColors entity while associating it with the relevant carId:

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

Key Points to Remember

Direct Insertion: Always insert related entities directly into their corresponding tables, specifying all required fields, such as foreign keys.

Cascade Operations: Understand when to use cascade operations. They can help with related entities but focus on the immediate data insertion first.

Testing: After executing your insert command, ensure to test your queries to confirm that the data appears as expected in the database.

Conclusion

By directly inserting related data into the appropriate entity, you can avoid the pitfall of null foreign keys and maintain the integrity of your database relationships. Using TypeORM with NestJS offers a powerful way to manage your PostgreSQL database, but it's essential to handle relational data correctly.

Now you're equipped to tackle similar issues in your TypeORM projects confidently. Happy coding!