NodeJS
How to connect multiple database in NodeJS
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Why do we use multiple databases ?
Multiple databases are useful in various situation
1) Microservice architecture: when each service has its own database.
2) Data segregation: You may need separate databases for different modules (e.g., userProducts, users).
3) Different Database Types: Connecting to both SQL and NoSQL databases in the same project.
Prerequisites
- NodeJS installed.
- TypeORM and the required database drivers installed.
- Basic knowledge of NodeJS and TypeORM.
connect multiple database in node with typeORM
Follow This Steps:
1) Step 1: Install Required Dependencies.
Note: Ensure you have TypeORM and the necessary database drivers for the databases you’re connecting. Example, PostgreSQL and MySQL.
npm install typeorm @nestjs/typeorm pg mysql2
2) Step 2: Create the Project
/src /entities userCart.ts userProducts.ts /modules userCart.module.ts product.module.ts app.module.ts main.ts /ormconfig ormconfig.userCart.ts ormconfig.product.ts Package.json
3) Step 3: Create ORM Configuration Files
- ormconfig.userCart.ts for userCart database
import { DataSource } from 'typeorm';
import { userCarts } from '../oc/src/shared/entity/userCarts'; export const userCartDataSource = new DataSource({ type: 'postgres', // database you want to use host: 'localhost', port: 5432, username: 'userCart_db_user', password: 'userCart_db_password', database: 'userCart_db', entities: [userCarts], synchronize: true, });
- ormconfig.product.ts for product database
import { DataSource } from 'typeorm';import { userProducts } from '/oc/src/shared/entity/userProducts';export const ProductDataSource = new DataSource({ type: 'mysql', // database you want to use host: 'localhost', port: 3306, username: 'userProducts_db_user', password: 'userProducts_db_password', database: 'userProducts_db', entities: [userProducts], synchronize: true,}); Step 4: Create Entities for Each Database
- userCart.ts Entity for the userCart Database
import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';
@Entity() export class userCart { @PrimaryGeneratedColumn() id: number; @Column(type: 'decimal',{ precision: 7, scale: 3, nullable: true}) totalItem: number;}Product.ts Entity for the Product Database import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';
@Entity()
export class userProducts {
@PrimaryGeneratedColumn()
id: number;
@Column()
name: string; }
Step 5: Initialize Data Sources in Your Application
- made configuration in your app.module.ts
import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';import { userCartModule } from 'oc/module/userCart.module';import { ProductModule } from 'oc/module/userProducts.module';import { UserDataSource } from 'oc/ormconfig/ormconfig.userCart';import { ProductDataSource } from 'oc/ormconfig/ormconfig.userProducts';@Module({ imports: [ // Import the userCart database connection TypeOrmModule.forRootAsync({ useFactory: () => userCartDataSource.options, }), // Import the product database connection TypeOrmModule.forRootAsync({ useFactory: () => ProductDataSource.options, }), userCartModule, ProductModule, ],})
export class AppModule {} Step 6: Implement Modules for userCart and Product
- user.module.ts
import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';import { userCart } from '../oc/src/shared/entity/userCarts';import { userCartService } from 'oc/user.service';@Module({ imports: [TypeOrmModule.forFeature([userCart])], providers: [userCartService],})export class userCartModule {}
product.module.ts
import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';import { userProducts } from '../oc/src/shared/entity/userProducts';import { userProductservice } from 'oc/product.service';@Module({ imports: [TypeOrmModule.forFeature([userProducts])], providers: [userProductservice],})export class ProductModule {}Step 7: Implement Services for Handling CRUD Operations
user.service.ts
import { Injectable } from '@nestjs/common';import { InjectRepository } from '@nestjs/typeorm';import { Repository } from 'typeorm';import { userCart } from '../oc/src/shared/entity/userCarts';@Injectable()export class userCartService { constructor( @InjectRepository(userCart) private userCartRepository: Repository<userCart>, ) {} finduserCartDetails(): Promise<userCart[]> { return this.userCartRepository.find(); }}product.service.ts
import { Injectable } from '@nestjs/common';import { InjectRepository } from '@nestjs/typeorm';import { Repository } from 'typeorm';import { userProducts } from '../oc/src/shared/entity/userProducts';@Injectable()export class userProductsService { constructor( @InjectRepository(userProducts) private userProductsRepository: Repository<userProducts>, ) {} findAll(): Promise<userProducts:[]> { return this.productRepository.find(); } create(product: userProducts): Promise<userProducts> { return this.productRepository.save(product); }}
Step 8: Run Your Application
npm run start
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