private function initScope(array $columns, array $fetch){
		$scope = [];
		foreach( $columns as $name=>$value ){
			$scope[$name] = ( isset($fetch[$name]) ) ? new Attribute($fetch[$name], false) : new Attribute($value, true);
			// Allow set null to field.
			if( $value === null ) $scope[$name]->allowNull();
		}
		return $scope;
	}