how to model multiple associations to one table

In my app plants are delivered to nurseries.

Deliveries can originate from nurseries or terminate there. Thus the deliveries table has two relations to the nurseries table with the corresponding fields being:

• from_nursery_id
• to_nursery_id

I can create an association for one of these in the delivery table:

static associations = {
  nursery: { type: 'belongs_to', key: 'from_nursery_id' }
}

But how can I build the second? An object cannot have two keys with the same name…

I had originally created them using other names:

static associations = {
  from_nursery: { type: 'belongs_to', key: 'from_nursery_id' },
  to_nursery: { type: 'belongs_to', key: 'to_nursery_id' }
}

Until watermelondb told me there were missing associations. Then I realized the key has to be the table name.

The same problem occurs at the other side of the relations, at the nursery table. There I originally had:

static associations = {
  from_delivery: { type: 'has_many', foreignKey: 'from_nursery_id' },
  to_delivery: { type: 'has_many', foreignKey: 'to_nursery_id' }
}

and it seems I can only add one of the two associations here too.

What will be the downsides of missing associations?

[KrisLau]

@radex Is this still not possible? I’m trying to do something similar

[g-nogueira]

As we are currently not able to execute joins (besides experimentalJoinTables and ), I believe the possibility to relate the same table multiple times is very important in many scenarios.

In my case, I have a “trainer_trainees” table that has the columns “trainer_id” and “trainee_id”. Both columns point to User.

BTW, thank you for the great work, @radex . After trying to use RxDB, I’ve being enjoying very much WatermlonDB for its simplicity.