SAP offers the so-called SAP BW/4HANA Model Transfer connection for the Data Warehouse Cloud (DWC). This makes it possible to integrate and reuse existing, including metadata (applications) from an SAP BW/4HANA system into the DWC without needing to set it up again manually.
Ingo Hilgefort from SAP has summarized very well in this blog through step by step instructions how this connection is to be set up. The amount of effort is distinctly more than with the ABAP live connection. This therefore begs the question as to just what the advantages of the Model Transfer connection are and what application scenarios it is suitable for. This blog contribution discusses this in detail.
SAP BW connection
The simplest form of access from the DWC to data in an SAP BW system is by using the SAP BW connection. In doing so it is possible to access individual tables, CDS views or data sources remotely or by means of replication. In the latter case the data is loaded cyclically into the DWC. Reporting is done on the data stored in the DWC. The tables can then be selected, filtered and combined with one another as desired in the DWC. Everything is possible, from a simple view of a table to a complex data model consisting of master and transaction data.
In practice, it is often the case that a BW data model already exists in the form of a query , which should be used in exactly the same way in the DWC. This query is thus based on multiple data sources: ADSOs and/or HANA Calculation Views for the transaction data, (as applicable) master data tables for navigation attributes and text tables for the texts (which may be time-or language-dependent, as applicable) on the metadata keys. Using the SAP BW connection, it is necessary to create all the objects individually in the DWC and then to combine them together by means of a view, for example. The number of objects and the associated amount of effort required to create them in the DWC quickly becomes large. The BW/4HANA Model Transfer connection is the best choice in such cases.
BW/4HANA Model Transfer connection
In the BW/4HANA Model Transfer connection whole data models are imported into the DWC on the basis of queries and hence all the objects can be created in an automated way. These are primarily all required BW sources, including connections, to be able to execute the query. The following looks in more detail as to which objects these are, and what is done with them.
Tables and views in the Data Builder
The corresponding remote tables with all the fields that are available in the BW are created in the data Builder for master data and transaction data objects.
The relevant tables of the BW Info objects (/BIC/P* and /BIC/M* and /BIC/T*) are taken over for the master data. A remote table is created for transaction data for the reporting provider that is used,, such as, for example, a HANA Composite Provider. In the same way, this is also possible via the SAP BW connection if the corresponding data source is imported into the Composite Provider instead of a table.
The corresponding views are also created for the remote tables with the BW/4HANA Model Transfer connection. In the case of master data the relevant views contain a selection of the active datasets and of the current calendar day as the reporting date. No language selection of the texts is done.
In the case of the views for the transaction data the navigation attributes of the BW Composite Provider are supplemented by a Left-Join with the corresponding master data views for the remote table described above. The view thus contains all the fields of the BW Composite Provider.
Data models in the Business Builder
The described views are combined with one another in two successive steps in the Business Builder.
First of all, texts and attributes are combined into an info object in a dimension. Analytic datasets are created for the transaction data, in which the existing dimensions are associated for the corresponding fields of the transaction data views.
In the following step a consumption model is then created that combines the characteristics and navigation attributes, including the associated texts and key figures of the query that had been imported at the beginning. Restricted and calculated key figures and elements of a key figures structure are also available as key figures.
A BW query is characterized by the fact that it contains a specific outline with specific selections and variables so that the user can extract the desired information as directly as possible. This task is handled in the DWC by the perspective, which at the same time is the last object presented here.
Perspectives are based on a consumption model and contain the characteristics and key figures that are actually to be displayed, in the same way as in the query that had been imported at the beginning. Query variables are not taken over, a constant value must already have been selected for release in the BW. However, it is possible add input parameters in the DWC perspective after the import operation. It is recommended that the perspectives should first of all be copied and the copies modified. Otherwise, the manual changes, such as for example after expanding the Composite Provider by another field, will be lost after the next import operation.
Summary
We showed how a data model that is represented by a BW query, can be filled with transaction data and the associated master data objects that have been imported into the DWC by using a SAP BW/4HANA Model Transfer connection. All the BW tables that are required for this are generated automatically. The generated DWV data model that ultimately can be consumed by the perspective is based on this.
It is also possible to use this in other DWC data models in addition to using the consumption models in the perspectives described here. The consumption models, and also individual tables or views, can be integrated into self-created models without any problems. In the case of sole use of the SAP BW connection all the tables must be imported individually and the model itself implemented. Even as a result if the number of objects can be kept down to be fewer, the amount of effort required is many times greater. The SAP BW/4HANA Model Transfer connection thus offers the option consume existing BW Queries into the DWC, quickly and without a great deal of effort. This is especially relevant if there are further data models that are implemented solely in the DWC and the user wishes to consume all the reports in the same system. A further application scenario is to combine the data of the BW query with additional data that only exists in the DWC.
