code: function(field, value) {
      var tmp = this.callParent(field, value)
  
      if (typeof field === 'object') {
        this.relations = this.relations || {}
  
        Object.keys(this.definition.relations).forEach(function(relationName) {
          if (field[relationName] !== undefined)
            this[relationName] = field[relationName]
        }, this)
      }
  
      return tmp
    }
docs: set relational data via it's parent + check if the given record(s) have a primary key set => update instead of create!