Overview of SAP HANA Modeling
How can a modeler use the SAP HANA features?
Combining data in SAP HANA happens in memory and is therefore fast. Therefore, a data modeler doesn’t need to store result sets from calculations, join, or union operations in new tables. Instead, views with joins or unions of existing physical tables can be defined during a model design. Only the definition must be stored as an SAP HANA calculation view. This is called a native SAP HANA model.
Even values from different physical tables can be combined into one result during the query execution. If a query accesses a view, the select statement is split into several statements reading from the underlying tables.
The view is typically created in the same SAP HANA system as the physical data tables. When data from different sources must be combined, data from other source systems can be copied to SAP HANA. You can copy data in the following ways:
- Import through batch with a delay in availability. You can do this once or periodically.
- Real time replication using a change data capturing method (either trigger-based or log-based) from a source table.
It's not only possible to read from physical tables of the same SAP HANA system. Instead of copying data, it's possible to create a virtual table. For a virtual table, only the table structure and other metadata are imported, and a reference to the remote data is generated.
A virtual table can be used in a view. When the view is read, the data is read from the remote source, following the reference of the virtual table.
In a view, extra filter definitions can be created to restrict the table content. Calculations and aggregation methods can be defined. All these calculations are carried out with high speed in memory.
SAP HANA modeling offers the following key features:
Fast data processing on demand
When you use views instead of storing results, query results are calculated only if needed and based on the most recent values. Then, formulas that are rarely executed need only be evaluated on the latest data records chosen in a report. Currency and unit conversion is processed with the current conversion factor.
Flexible SQL based models
If you’re used to generating new values by using SQL statements, continue to build views and procedures with the full power of the SQL script. You can go beyond SAP BW/4HANA standard techniques, even without ABAP knowledge.
- More modeling features, such as:
- Fuzzy search. For example, to find the best match.
- Geospatial modeling. For example, answering the question: "What is the store closest to a particular customer?"
- SAP HANA Graph. For example, the shortest path.
Aggregation on existing tables
If you want to enable aggregation of results on any level of granularity, you can store the values on the most detailed level without redundancy, and let SAP HANA calculate sum values in memory. This is called lightweight modeling and consumption. You can access the result without intermediate tools based on open standards (SQL, MDX, ODATA).
Reduce the data footprint.
Data can be combined in a virtual data model using SAP HANA calculation views (column views) with filters and calculations. Less physical data storage space is needed.