public function reset($mapper = true) {
		if ($mapper)
			$this->mapper->reset();
		$this->fieldsCache=[];
		$this->saveCsd=[];
		$this->countFields=[];
		$this->preBinds=[];
		$this->grp_stack=null;
		// set default values
		if (($this->dbsType == 'jig' || $this->dbsType == 'mongo')
			&& !empty($this->fieldConf))
			foreach($this->fieldConf as $field_key => $field_conf)
				if (array_key_exists('default',$field_conf)) {
					$val = ($field_conf['default'] === \DB\SQL\Schema::DF_CURRENT_TIMESTAMP)
						? date('Y-m-d H:i:s') : $field_conf['default'];
					$this->set($field_key, $val);
				}
	}