TM1 Forum

Does a cube lose data if you change the type of an element?

We have changed an element within a dimension by mistake from simple to consolidated . When changing back to the simple element it appears that we have lost the data within the cube against the element - Is this the case and if so would we need to go to a backup and copy over an older version of the cube?

Yes this is expected behavior. When changing an element type from N to C what happens in the background is destruction of the leaf element and creation of a new consolidated element of same name. As in TM1 cubes numeric data is only stored at leaf level any data associated with the old leaf element will be lost.

This is why any changes of element type in TM1 need to be really well planned and any numeric data usually needs to be migrated prior to the actual element substitution.

Sorry if it's too obvious, but I wanted to add that you see 0 on the new consolidated element, since there are no children.
Hence, TM1's normal behaviour of consolidations showing the sum of the components, is working. It's only adding up nothing given the absence of components.

You may not have to go to backup. This used to work as long as you hadn't issued a SaveData since the dimension was updated:

1. Go to the data directory and copy the .cub file to another location
2. Restore the N level element to it's proper place with the dimension editor.
3. Stop the TM1 Server.
4. Copy the .cub file from step 1 back into the data directory.
5. Restart the TM1 Server.

I haven't had to do this in a while but it used to work, at least up to version 9.4. I doubt IBM has changed this.

thanks folks...problem now resolved