TL;DR
- Create database provider by useFactor here
- Create database module import database provider and export
- Create your entity and make own provider by inject database provider here
- import own provider to use in service
1) Create NestJS application with command line
nest new ${YOUR_APP_NAME}
cd ${YOUR_APP_NAME}
2) Create database folder for collect database connector
mkdir database
3) Make Database Provider by use useFactory
useFactory syntax allows for creating providers dynamically
You can connect multi database source
/*
<project path>/src/database/database.provider.ts
*/
import * as mongoose from 'mongoose';
export const firstDatabaseProvider = {
provide: '<Provider name>',
useFactory: async (): Promise<mongoose.Connection> => {
return await mongoose.createConnection('<MongoDB URI>')
}
}
export const secondDatabaseProvider = {
provide: '<Provider name>',
useFactory: async (): Promise<mongoose.Connection> => {
return await mongoose.createConnection('<MongoDB URI>')
}
}
4) Make Database module
/*
<project path>/src/database/database.module.ts
*/
import * as mongoose from 'mongoose';
import { firstDatabaseProvider, secondDatabaseProvider } from './database.provider';
@Module({
providers: [firstDatabaseProvider, secondDatabaseProvider],
exports: [firstDatabaseProvider, secondDatabaseProvider],
})
export class DatabaseModules {}
5) Run below command line to create CRUD application by nest-cli
nest g res ${YOUR_ENTITY}
cd ${YOUR_ENTITY}
6) Create entity provider by go to file ${YOUR_ENTITY}.provider.ts
You can learn how to create model, mongoose schema and mongoose document in NestJS docs Here
import { Connection } from 'mongoose';
import { Entity ,EntitySchema } from './entities/yourEntity';
// use second database
import { secondDatabaseProvider } from '../database/database.provider'
export const myEntityProviders = [
{
provide: '<First Entity Provider Name>',
useFactory: (connection: Connection) => connection.model(Entity.name, EntitySchema),
inject: [financialDocDBProvider.provide],
},
]
7) make service
// ${YOUR_ENTITY}.service.ts
import { Inject, Injectable } from '@nestjs/common';
import { Model } from 'mongoose';
import { myEntityDocument } from './entities/entity.entity';
import { myEntityProviders } from './entity.provider';
@Injectable()
export class EntityService {
constructor(@Inject(myEntityProviders[0].provide) private entityModel: Model<myEntityDocument>) {}
async create(): Promise<myEntityDocument> {
const newObj = new this.entityModel()
return newObj.save();
}
findAll(): Promise<myEntityDocument[]> {
return this.entityModel.find().exec();
}
}
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