Foreign keys

Foreign keys are changed from inside altertable with three keys: add_foreign_key, modify_foreign_key and drop_foreign_key.

Add foreign key

add_foreign_key takes an array of constraints. name, from, references and to are required; on_delete is optional.


{
  "altertable": {
    "orders": {
      "add_foreign_key": [
        {
          "name": "orders_account_fk",
          "from": "account_id",
          "references": "accounts",
          "to": "id"
        }
      ]
    }
  }
}

Modify foreign key

modify_foreign_key has the same shape as add_foreign_key. Because a constraint cannot be changed in place, it is compiled to a drop of the existing constraint (by name) followed by adding it again with the new definition.


{
  "altertable": {
    "orders": {
      "modify_foreign_key": [
        {
          "name": "orders_account_fk",
          "from": "account_id",
          "references": "accounts",
          "to": "id",
          "on_delete": "cascade"
        }
      ]
    }
  }
}

Drop foreign key

drop_foreign_key takes an array of constraint names.


{
  "altertable": {
    "orders": {
      "drop_foreign_key": ["orders_account_fk"]
    }
  }
}