Many-to-Many Relationship

[blalan05]

Is your feature request related to a problem? Please describe.
I'd like to create complex relationship with through tables.

User
id
name

UserToType
userId
userTypeId

UserType
id
name

Describe the solution you'd like
Add the ability to define Many-to-Many relationships

Describe alternatives you've considered
I think its possible to define through table manually, then use the relationship definition like One-to-Many.

Additional context
Add any other context or screenshots about the feature request here.

[kk7771]

Is there any progress? I also encountered the same problem.
@noam-honig

[noam-honig]

Hi @balan05 & @Vincent1016 - sorry for not replying earlier

In the current version of remult, you can do that with a 'through' table

@Entity('users')
class User {
  @Fields.cuid()
  id = ''
  @Fields.string()
  name = ''
}
@Entity('UserTypes')
class UserType {
  @Fields.cuid()
  id = ''
  @Fields.string()
  name = ''
}
@Entity<UserToType>('UsersToTypes', {
  id: (e) => [e.userId, e.typeId],
})
class UserToType {
  @Fields.string()
  userId = ''
  @Fields.string()
  typeId = ''
}

You can employ advanced filtering techniques as detailed in:
https://remult.dev/docs/techniques-regarding-one-to-many-relations.html

You can also add many to one relations to the mix - but in that case, at the current version, I recommend adding a separate id column for good measure

@Entity<UserToType>('UsersToTypes')
class UserToType {
  @Fields.cuid()
  id = ''
  @Field(() => User, { lazy: true //to only load when requested 
    })
  userId!: User
  @Field(() => UserType)
  typeId!: UserType
}

You can use lazy to control if the other row is loaded by default or not - see:
https://remult.dev/docs/lazy-loading-of-related-entities.html#lazy-loading-of-related-entities

We are currently planning some improvements in the relations area, stay tuned

[kk7771]

@noam-honig
good job。 remult is great.

[mihaa1]

Hi @balan05 & @Vincent1016 - sorry for not replying earlier

In the current version of remult, you can do that with a 'through' table

@Entity('users')
class User {
  @Fields.cuid()
  id = ''
  @Fields.string()
  name = ''
}
@Entity('UserTypes')
class UserType {
  @Fields.cuid()
  id = ''
  @Fields.string()
  name = ''
}
@Entity<UserToType>('UsersToTypes', {
  id: (e) => [e.userId, e.typeId],
})
class UserToType {
  @Fields.string()
  userId = ''
  @Fields.string()
  typeId = ''
}

You can employ advanced filtering techniques as detailed in: https://remult.dev/docs/techniques-regarding-one-to-many-relations.html

You can also add many to one relations to the mix - but in that case, at the current version, I recommend adding a separate id column for good measure

@Entity<UserToType>('UsersToTypes')
class UserToType {
  @Fields.cuid()
  id = ''
  @Field(() => User, { lazy: true //to only load when requested 
    })
  userId!: User
  @Field(() => UserType)
  typeId!: UserType
}

You can use lazy to control if the other row is loaded by default or not - see: https://remult.dev/docs/lazy-loading-of-related-entities.html#lazy-loading-of-related-entities

We are currently planning some improvements in the relations area, stay tuned

Hey,
Related - when using relations as in docs - should an underlying foreign key be created?
Im using postgres - either I'm missing something or it is not created

[noam-honig]

Hi @mihaa1

No, at this time we do not generate a foreign key in the db by default - we only generate the structure to store the data, and leave it to the developer to create the meta data objects such as indexes, foreign keys etc...

You can easily do that as part of the version update process discussed in:
#162

[mihaa1]

Hi @mihaa1

No, at this time we do not generate a foreign key in the db by default - we only generate the structure to store the data, and leave it to the developer to create the meta data objects such as indexes, foreign keys etc...

You can easily do that as part of the version update process discussed in: #162

Thanks.
Rules of relations are enforced by code then inside remult?
e.g. creating relation with non existent id

[noam-honig]

Not at this time - I enforce it in my application code, not by remult.

…

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