How to connect to remote oracle database using typeorm in nestjs? - oracle

Question

I was wondering how to connect to remote oracle database from nestjs using typeorm.
I installed typeorm and oracle package using following command.
npm i --save #nestjs/typeorm typeorm oracle
npm install oracledb --save
and then tried configuring in app.module.ts using TypeOrmModule.forRoot but it was not succesfull.
Here are my configuration settings.
TypeOrmModule.forRoot({
type: 'oracle',
host: 'ip of hostname',
port: port number,
username: 'username',
password: 'password',
serviceName: 'servicename',
synchronize: false,
entities: []
})
Can anybody help me out what am I missing? Also would like to know how can I execute the query once this connection is succesfully? If any example that would be helpfull.

Answer 1

Got it.
one missing thing was database name.
Added
database: 'databasename' in above configuration and it worked.
But, still my question is how to use this connection in service to fetch/push the data from/to oracle databse?

Answer 2

If you provide a name in your connection details you should be able to refer to the database connection using that. Otherwise, if no name is provided I believe it assigns it the name 'default'.
Basically these are the steps you should perform to use the database connection: (examples below each)
Create a model - this is how TypeORM knows to create a table.
export class Photo {
id: number
name: string
description: string
filename: string
views: number
isPublished: boolean
}
Create an Entity. - this should match your model, with the appropriate decorators. At minimum you should have the #Entity() decorator before your class definition and #Column() before each field.
import { Entity, Column } from "typeorm"
#Entity()
export class Photo {
#Column()
id: number
#Column()
name: string
#Column()
description: string
#Column()
filename: string
#Column()
views: number
#Column()
isPublished: boolean
}
Create your data source - looks like you have already done this. But I would give it a name field and you will need to pass your entities into the entity array you have.
const AppDataSource = new DataSource({
type: "postgres",
name: "photos",
host: "localhost",
port: 5432,
username: "root",
password: "admin",
database: "test",
entities: [Photo],
synchronize: true,
logging: false,
})
Then you can use repositories to manage data in the database:
const photo = new Photo()
photo.name = "Me and Bears"
photo.description = "I am near polar bears"
photo.filename = "photo-with-bears.jpg"
photo.views = 1
photo.isPublished = true
const photoRepository = AppDataSource.getRepository(Photo)
await photoRepository.save(photo)
console.log("Photo has been saved")
const savedPhotos = await photoRepository.find()
console.log("All photos from the db: ", savedPhotos)
For more details I would spend some time reading through the typeORM website, all the examples I pulled were from there:
https://typeorm.io/