I need to save an entity, which is related to another entity that has 2 foreign keys on NESTusing TypeORM

Question

I'm going to simplify this, I have 3 entities.

//1er entity
@Entity()
export class Song{

@PrimaryGeneratedColumn('uuid')
SongId: string;

@Column()//this is a UserId
Owner: string;

@OneToMany( type => Lyric, lyric => lyric.Song, {
cascade: true
})//I supposed different versions
Lyrics: Lyric[];
}

//2nd entity
@Entity()
export class Usuario {

@PrimaryGeneratedColumn('uuid')
UsuarioId: string;

@ManyToMany(type => Song, song => Song.songId)
@JoinTable()
Songs: Song[] | null;

@OneToMany( type => Lyric, lyric => lyric.User)
Lyrics: Lyric[] | null;

//3er entity
@Entity()
export class Lyric{
@PrimaryGeneratedColumn('uuid')
LyricId: string;

@Colum()
lyric: string;    

@ManyToOne( type => User, user => user.Lyrics)
User: User;

@ManyToOne( type => Song, song => song.Lyrics)
Song: Song;
}

So I have my user created, no songs or lyrics, but I have his id

user = {
UserId = '0433bd30-e21d-4581-8906-a5ee1a5b23d4',
Songs = [],
Lyrics = []
}

When I am creating a song I need my UserId and my lyric or lyrics

const song= this.repository.create({
userId,
Lyrics
})

I was trying this on my Lyrics

Lyrics = [
{
UserId: userId,
Lyric: 'hello, hello, this is the lyric, etc etc'
},
{
UserId: userId,
Lyric: 'hello again, hello, this is the lyric, etc etc'
},
]

So i try to save my song

await this.repository.save(cancion)

All it's ok, but my Lyric entity only get the SongId and UserId is empty

enter image description here

So what Im doing righ now is make two saves, but idw if I can get this doing only one

That's what Im doing right now

Lyrics.forEach(async lyric=> {
const newLyricWithUserAndSong : CreateLyricDto = {
SongId: song.songId,// this is my first save await this.repository.save(song)
...lytic
}

await this.lyricService.create(newLyricWithUserAndSong )

I think there is a bad configuration with the entities, when I save a song everything works correctly, but my lyrics entity only takes SongId and UserId is empty

What do u think about it?

Answer 1

Part #1

@PrimaryGeneratedColumn('uuid')
SongId: string;

and

@ManyToMany(type => Song, song => Song.songId)
@JoinTable()
Songs: Song[] | null;

There is no property songId on Song. There is a property SongId.

---

Part #2

Check better this part:

const newLyricWithUserAndSong : CreateLyricDto = {
SongId: song.songId,// this is my first save await this.repository.save(song)
...lyric
}

If lyric comes with empty/undefined SongId, it will get overwritten, because it comes after SongId. Besides SongId and songId are different props.

---

Part #3

What's the use of defining reverse relationship to Lyrics on User? Leave user on Lyrics only, and you'll still be able to fetch lyrics for given user. And there will be one entity to save. Similarly, only Lyrics need relation to Song. Song doesn't need to have reverse relation with lyrics. If I'm getting your struggle well, that should save you a loooooot of hassle. You'll only update Lyrics, and still be able to fetch lyrics for song, songs for one lyrics, user for lyrics, and lyrics for user.

Besides, that's what TypeORM does, I guess?

---

Part #4

Switch to MikroORM :D