lib/components/dataInterface/connectors/db/Model.php
public function findPrimaryKeys($params = [])
    {
        $q = $this->find($params);
        $q->select($this->_tableName . '.' . $this->meta->schema->primaryKey[0]);

        return $q->column($this->interface->db);
    }
public function findPrimaryKeys($params = [])
    {
        $q = $this->find($params);
        $q->select($this->_tableName . '.' . $this->meta->schema->primaryKey[0]);

        return $q->column($this->interface->db);
    }
Return the primary keys (used in lazy loading).

@param array $params find params for the query [optional]

@return array keys from the data source items