SAP BW DataStore object (DSO)
A BW DataStore Object is the object which represents a flat physical table.
In a dataflow, it is typically used as an Enterprise Data Warehouse layer, to store (historical) transactional data before it is transferred to the reporting layer. It is also the object where the delta is processed and SID’s are generated.
For reporting it should only be used to list transactional data on the lowest level of detail.