Dear
The R/3 enhancement concept allows you to add your own functionality to SAPu2019s standard business applications without having to modify the original applications. These exits do not contain any functionality. Instead, the customer exits act as hooks. You can hang your own add-on functionality onto these hooks.
Five ways to enhance SAP BI Backend functioanlity using ABAP
1. Data Extraction
2. Data Stating
3. BEx variables
4. Virtual Infocubes, KF and Characteristics
5. ABAP in process chains
Regards