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Relations

Once relations are declared in the protocol, you can walk them inside any projection — at any depth.

A user with their orders​

mydb.users{
  id,
  name,
  orders{id, total, status}
}

orders here isn't a column. It's a relation defined on the users entity in the protocol. ONQL fetches the related rows and embeds them in the response.

Nest as deeply as you like​

mydb.users{
  id,
  name,
  orders{
    id,
    total,
    items{name, qty, price}
  }
}

Filter inside a relation​

You can apply a filter to the related table the same way you would on a top-level table:

mydb.users{
  id,
  name,
  orders[status = "paid"]{id, total}
}

For a one-to-one relation, the result is a single object instead of an array:

mydb.users{
  id,
  name,
  profile{avatar_url, bio}
}

Reverse traversal​

Walking from the "many" side to the "one" side works exactly the same way:

mydb.orders{
  id,
  total,
  user{id, name}
}

Whether the underlying relation is oto, otm, mto, or mtm, the syntax in your query is identical. The shape of the response (array vs object) follows from the relation type.

What's next​

Time to crunch numbers with aggregates.