Embodiments provide a multi-buffering system in an application layer to support unified read/write access to different data source types of an underlying database layer. In a particular embodiment, the database layer comprises both a multi-dimensional data source (e.g. a cube), and another data source type (e.g. a Data Store Object—DSO). An abstract buffer component of the multi-buffering system is specialized into a delta buffer configured to read/write data of the cube, and into an after image buffer configured to read/write data of the DSO. A storage mechanism component of the multi-buffering system is specialized into a cache store configured to read/write data of the cube, and a calculation scenario store configured to read/write data of the DSO. The after image buffer may support certain aggregation rules during a DSO read/write operation. The calculation scenario store may leverage capabilities of an in memory database during a DSO read/write operation.