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Many-to-One

A many-to-one relation is the reverse of one-to-many. Many rows on this side, one row on the other.

Example​

Many orders belong to one user.

Protocol​

"orders": {
  "relations": {
    "user": {
      "type": "mto",
      "entity": "users",
      "prototable": "users",
      "fkfield": "user_id:id"
    }
  }
}

Note the fkfield reads in the opposite direction from otm: the order's user_id matches the user's id.

Query​

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

Response shape​

Like oto, the related side is a single object:

{
  "orders": [
    { "id": 100, "total": 99, "user": { "id": 1, "name": "Ada" } }
  ]
}

When to use it​

Use mto whenever you want to attach the parent record to each child:

  • Order → user
  • Comment → post
  • Trade → instrument
  • Position → account

Tip​

It's normal — and recommended — to declare both otm and mto for the same relationship from each side. The protocol is symmetrical: the user has orders (otm) and the order has user (mto).