DB partitioning vs semantic partition objects

Hi,

I have some question about DB partitioning and semantic partition objects. I checked online but still I'm confuse.

I would like to understand the following things.

1) what is the difference between DB partitioning and semantic partition objects

2) what are the scenarios there we can specifically say here we need to use DB partioning or semantic partion object.

3) can you create db partion on semantic partion object base cube

Please reply me.

Thanks