Many-to-one / one-to-many relations

import {Entity, PrimaryGeneratedColumn, Column, OneToMany} from "typeorm";
import {Photo} from "./Photo";
@Entity()
export class User {
    @PrimaryGeneratedColumn()
    id: number;
    @Column()
    name: string;
    @OneToMany(type => Photo, photo => photo.user)
    photos: Photo[];

Here we added @OneToMany to the photos property and specified the target relation type to be Photo.You can omit @JoinColumn in a @ManyToOne / @OneToMany relation.@OneToMany cannot exist without @ManyToOne.If you want to use @OneToMany, @ManyToOne is required. However, the inverse is not required: If you only care about the @ManyToOne relationship, you can define it without having @OneToMany on the related entity.Where you set @ManyToOne - its related entity will have “relation id” and foreign key.

This example will produce following tables:

const photo1 = new Photo();
photo1.url = "me.jpg";
await connection.manager.save(photo1);
const photo2 = new Photo();
photo2.url = "me-and-bears.jpg";
await connection.manager.save(photo2);
const user = new User();
user.name = "John";
user.photos = [photo1, photo2];
await connection.manager.save(user);

or alternative you can do:

With cascades enabled you can save this relation with only one save call.

const userRepository = connection.getRepository(User);
const users = await userRepository.find({ relations: ["photos"] });
// or from inverse side
const photoRepository = connection.getRepository(Photo);

Or using QueryBuilder you can join them:

With eager loading enabled on a relation you don’t have to specify relation or join it - it will ALWAYS be loaded automatically.