As explained in External SAP HANA Views and Navigation Attributes, navigation attributes are not always supported in External SAP HANA Views. In the following we take a closer look at examples where navigation attributes are based on compounded characteristics. Basically we have three scenarios when it is about the mapping of compounded characteristics in a HCPR. Let's use an example for discussing these possibilities: the delivered characteristic 0REGION is compounded with 0COUNTRY(called compounding father) which means that only the concatenated value defines a region in a unique way. Our sample HCPR is based on three ADSOs and contains 0REGION and 0COUNTRY:
HCPR Mapping:
- PartProvider ADSO1: simple one-to-one mapping
- 0REGION and 0COUNTRY from ADSO1 are assigned to 0REGION and 0COUNTRY on HCPR level.
- PartProvider ADSO2: CMP problem
- only 0COUNTRY from ADSO2 is assigned to 0COUNTRY on HCPR level. This mapping leads to the so called CMP problem, see CMP(Compounding) Problem.
- PartProvider ADSO3: unsupported mapping
- only 0REGION from ADSO3 is assigned to 0REGION on HCPR level. In general this mapping is not supported since it might lead to misleading/unexpected query results.
The mappings 2 and 3 have consequences which lead to the fact that navigation attributes of 0REGION cannot be used in the External Hana view of the HCPR:
Page under Construction.....
Example to Mapping Variant 2
Example to Mapping Variant 3
The following simple HCPR uses the mapping variant 3 regarding the characteristic STPE_REG which is compounded with 0COUNTRY: the partprovider STPE_AD11 contains STPE_REG and 0COUNTRY, but only STPE_REG is mapped in the HCPR. In addition we activate the navigation attribute STPE_REG__STPEDSTR3:
If you check the definition of the HCPR you get the warning "InfoProvider HMOD & CMP is not defined correctly. Compounding of "STPE Region"[STPE_REG] is incorrect - BRAIN 152" displayed. Normally it makes no sense to omit the mapping of 0country since only the concatenated value defines a region in a unique way. The system allows the activation but it is highly recommend to avoid such scenarios since it might lead to misleading/unexpected query results. In addition it means that it is not possible to join the master data table of STPE_REG on the partprovider level(to get the attribute values) which can lead to performance problems. In addition such a navigation attribute cannot be used in a corresponding External SAP Hana view. See also example below.
After activation you can find the warning "Navigation attribute STPE_REG__STPEDSTR3 is excluded from the external SAP HANA view - RS2HANA_VIEW 151" in the log:
We now run the so called Adhoc Query in Transaction RSRT and take a look at the statements used to retrieve data from the database. When we add the navigation attribute to the drilldown we can see that the system creates a Hana calculation view on the fly where the HCPR is joined with the master data table(X-table) of STPE_REG. Such a join on the top level of the HCPR can have a negative impact on the query performance. In addition such a procedure cannot be included into an External SAP Hana view and therefore corresponding navigation attributes are excluded from the External SAP HANA view.
