事务与迁移

import { DataSource, Entity, PrimaryGeneratedColumn, Column, Repository } from 'typeorm';

@Entity()
export class Account {
  @PrimaryGeneratedColumn() id: number;
  @Column({ type: 'decimal', precision: 10, scale: 2 }) balance: number;
}

async function runTransaction() {
  const AppDataSource = new DataSource({
    type: 'sqlite',
    database: ':memory:',
    entities: [Account],
    synchronize: true,
  });

  await AppDataSource.initialize();
  const accountRepo = AppDataSource.getRepository(Account);

  await AppDataSource.transaction(async manager => {
    const sender = await manager.save(accountRepo.create({ balance: 100 }));
    const receiver = await manager.save(accountRepo.create({ balance: 50 }));

    console.log(`Initial: Sender ${sender.balance}, Receiver ${receiver.balance}`);

    sender.balance -= 20;
    receiver.balance += 20;

    await manager.save(sender);
    // Simulate an error here to trigger rollback:
    // throw new Error('Failed to update receiver!');
    await manager.save(receiver);

    console.log(`Final: Sender ${sender.balance}, Receiver ${receiver.balance}`);
  });

  await AppDataSource.destroy();
}

// To run this in a Node.js context:
// runTransaction().catch(console.error);
// For CoddyKit, we just show the code.

import { Injectable } from '@nestjs/common';
import { Repository, EntityManager } from 'typeorm';
import { InjectRepository } from '@nestjs/typeorm';
import { Transaction } from 'typeorm'; // Import Transaction decorator

// Assume Account Entity is defined elsewhere
class Account { 
  id: number; 
  balance: number; 
}

@Injectable()
export class BankService {
  constructor(
    @InjectRepository(Account) private accountRepository: Repository<Account>,
  ) {}

  @Transaction()
  async transferFunds(
    senderId: number,
    receiverId: number,
    amount: number,
    @TransactionManager() manager?: EntityManager, // Manager is injected
  ): Promise<boolean> {
    const accountManager = manager || this.accountRepository.manager; // Use injected manager

    const sender = await accountManager.findOneBy(Account, { id: senderId });
    const receiver = await accountManager.findOneBy(Account, { id: receiverId });

    if (!sender || !receiver || sender.balance < amount) {
      throw new Error('Transfer failed: Invalid accounts or insufficient funds');
    }

    sender.balance -= amount;
    receiver.balance += amount;

    await accountManager.save(sender);
    await accountManager.save(receiver);

    console.log(`Transferred ${amount}. Sender: ${sender.balance}, Receiver: ${receiver.balance}`);
    return true;
  }
}

// Note: This code is illustrative within a NestJS service context. 
// It's not runnable as a standalone script without a full NestJS setup.

import { MigrationInterface, QueryRunner, Table } from 'typeorm';

export class MyNewMigration1678886400000 implements MigrationInterface {
  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.createTable(
      new Table({
        name: 'products',
        columns: [
          { name: 'id', type: 'int', isPrimary: true, isGenerated: true, generationStrategy: 'increment' },
          { name: 'name', type: 'varchar' },
          { name: 'price', type: 'decimal', precision: 10, scale: 2, default: 0 },
        ],
      }),
      true,
    );
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.dropTable('products');
  }
}