public function set(array $columns_and_values) {
		// for each provided strict condition
		foreach($columns_and_values as $column => $value) {
			// secure the column name
			list($column, $placeholder) = Query\Convert::columnToPlaceholder($this->Quote ,$column);
			// save the condition
			$this->Updates[] = "{$column} = :{$placeholder}";
			// save the value (converted if necessary)
			$this->Values[":{$placeholder}"] = Query\Convert::valueForDatabase($column,$value);
		}
		// return self to the next method
		return $this;
	}