I have a setup for my NestJS application in which I am using typeorm with a PostgreSQL database. In the setup, I am using repository mode to query the database. Now I want to use database transactions with my queries, but I am not able to use transactions because I am using one transaction with multiple queries from different repositories, and a transaction uses an entity manager, which has to be used to query the database in order to access the same transaction for all the queries in the scope.

Entity One

@Injectable()
export class EntityOneService extends BaseService<EntityOne> {
  repository: Repository<EntityOne>;
  constructor(private connection: Connection) {
    super();
    this.repository = this.connection.getRepository(EntityOne);
  }
}

Entity Two

import { Injectable } from '@nestjs/common';
import { Connection, Repository } from 'typeorm';

import { EntityTwo } from '../entities/lesson.entity';
import { BaseService } from './baseService/base-service.service';

@Injectable()
export class EntityTwoService extends BaseService<EntityTwo> {
  repository: Repository<EntityTwo>;
  constructor(private connection: Connection) {
    super();
    this.repository = this.connection.getRepository(EntityTwo);
  }
}

This is how to initialize the repository from a database table. Now I want to query the database using transaction in repository mode.

const entityOne = await this.entityOneService.find()
const entityTwo = await this.entityTwoService.find()

I want to query both with the same transaction. I have user sequelize before typeorm, and in sequelize there is a method named transaction which can used as follows.

this.sequelize.transaction(async transaction => {
    const entityOne = await this.entityOneService.findAll({transaction})
    const entityTwo = await this.entityTwoService.findAll({transaction})
})

I want to do something like that in typeorm, if possible how can I implement it?

CodePudding user response：

Transactions

• Creating and using transactions
• Using QueryRunner to create and control state of single database connection

Creating and using transactions

Transactions are created using DataSource or EntityManager. Examples:

await myDataSource.transaction(async (transactionalEntityManager) => {
  // execute queries using transactionalEntityManager
});

or

await myDataSource.manager.transaction(async (transactionalEntityManager) => {
  // execute queries using transactionalEntityManager
});

Everything you want to run in a transaction must be executed in a callback:

await myDataSource.manager.transaction(async (transactionalEntityManager) => {
  await transactionalEntityManager.save(users);
  await transactionalEntityManager.save(photos);
  // ...
});

Using QueryRunner to create and control state of single database connection

QueryRunner provides a single database connection. Transactions are organized using query runners. Single transactions can only be established on a single query runner. You can manually create a query runner instance and use it to manually control transaction state. Example:

// create a new query runner
const queryRunner = dataSource.createQueryRunner();

// establish real database connection using our new query runner
await queryRunner.connect();

// now we can execute any queries on a query runner, for example:
await queryRunner.query("SELECT * FROM users");

// we can also access entity manager that works with connection created by a query runner:
const users = await queryRunner.manager.find(User);

// lets now open a new transaction:
await queryRunner.startTransaction();

try {
  // execute some operations on this transaction:
  await queryRunner.manager.save(user1);
  await queryRunner.manager.save(user2);
  await queryRunner.manager.save(photos);

  // commit transaction now:
  await queryRunner.commitTransaction();
} catch (err) {
  // since we have errors let's rollback changes we made
  await queryRunner.rollbackTransaction();
} finally {
  // you need to release query runner which is manually created:
  await queryRunner.release();
}

There are 3 methods to control transactions in QueryRunner:

• startTransaction - starts a new transaction inside the query runner instance.
• commitTransaction - commits all changes made using the query runner instance.
• rollbackTransaction - rolls all changes made using the query runner instance back.

Source: https://typeorm.io/transactions

CodePudding user response：

https://stackoverflow.com/a/70140732 I think this is an example for a solution with multiple repositories.