How to replace missing values with the last given Value

Hello,

i have a Database with the following scheme:

+-----------+----------------+
| Field      | Type            |
+-----------+----------------+
| object    | varchar(50) |
| attribute | int(11)         |
| value     | float            |
| date       | datetime      |
+-----------+----------------+

Object = manufacturing plant

attribute = Sensor name

Value = sensor value

date = timestamp (datetime)

The Idea is to only save an attribute, when the value hase changed (triggered by change)...

In Rapidminder i am able to transform the scheme back to the traditional scheme, where every attribute/Sensor has a collumn. Only problem i have, are the missing values. If there are no values it means the haven`t changed, so i`d like to replace the missing values with the last given value. Is there a way to accomplish this ?

If it is not clear what exacty my problem is, i can try to be more precise in explaining it.

Thank you for your reply/ help