TypeORM: How to Connect to Multiple Database

In TypeORM, you can simply connect to multiple databases simultaneously just by creating multiple data sources.

The Steps

1. Setup your data sources:

xport const dataSourceOne = new DataSource({
  database: 'kindacode_example',
  entities: [User, Post, Comment],
  type: 'postgres',
  port: 5432,
  host: 'localhost',
  username: 'snowball',
  password: '123456',
  synchronize: true,
});

export const dataSourceTwo = new DataSource({
  database: 'other_db',
  entities: [Product, Order],
  type: 'postgres',
  port: 5432,
  host: 'localhost',
  username: 'badman',
  password: 'supersecret',
  synchronize: true,
});

2. The next step is to initialize the connections (usually placed in the entry file of your project like app.js, index.js, server.js, etc):

import { dataSourceOne } from '...';
import { dataSourceTwo } from '...';

/* Put these lines in an async function */
await dataSourceOne.initialize();
await dataSourceTwo.initialize();

3. And you can do communication with the database as follows:

import { dataSourceOne } from '...';
import { dataSourceTwo } from '...';

/* Place these code lines in an async function */
const userRepository = dataSourceOne.getRepository(User);
const users = await userRepository.find();
console.log(users);

const productRepsoitory = dataSourceTwo.getRepository(Product);
const products = await productRepsoitory.find();
console.log(products);

Note that connected database types can be different (PostgreSQL, MySQL, MongoDB, etc). If you run into errors, try to update typeorm to the latest version.

Further reading:

• TypeORM: ORDER BY Multiple Columns
• TypeORM: How to Execute Raw SQL Queries
• TypeORM Upsert: Update If Exists, Create If Not Exists
• TypeORM: Find Rows Where Column Value is IN an Array
• TypeORM: Selecting Rows with Null Values

You can also check out our database topic page for the latest tutorials and examples.