This video tutorial focuses on how to write a start routine using HANA Script in BW4HANA. The presenter uses a system of BW4HANA to demonstrate the process. The tutorial covers the differences between ABAP routines and HANA script routines, the structure of the start routine, and how to perform a lookup in the start routine. The presenter also explains how to write the code for the start routine, how to activate it, and how to execute it.

Key Topics covered in the video session:

1. Introduction to the System and Scenario: The presenter introduces the BW4HANA system and the scenario for the tutorial. The scenario involves filtering data from a source based on certain criteria. The presenter explains the necessity of filtering data in the transformation rather than at the DTP level.
2. Writing the Start Routine: The presenter demonstrates how to write the start routine in HANA Studio. The start routine is written using AMDP, and the presenter explains the difference between ABAP routines and HANA script routines.
3. Understanding the Structure of the Start Routine: The presenter explains the structure of the start routine, including the use of IN and OUT tables. The presenter also explains the difference between the application layer and the database layer.
4. Performing a Lookup in the Start Routine: The presenter demonstrates how to perform a lookup in the start routine. This involves declaring the lookup table in the method declaration part of the routine and writing the SQL code for the lookup.
5. Activating and Executing the Start Routine: After writing the start routine, the presenter shows how to activate the routine and execute it using a DTP. The presenter also explains how to check the results of the routine.
6. Explaining the Differences between ABAP and HANA Script Routines: The presenter explains the differences between ABAP routines and HANA script routines. ABAP routines are executed at the application layer level, while HANA script routines are executed at the database level. This difference affects the speed and efficiency of the routines.
7. Conclusion: The presenter concludes the tutorial by summarizing the key points covered in the video. The presenter emphasizes the importance of understanding the differences between ABAP routines and HANA script routines and the benefits of using HANA script routines in BW4HANA.