Core Data Services (CDS) as the name suggests, is a service directly by HANA core. To present CDS in a very understandable manner, CDS is a view of one or multiple tables and can be enriched with metadata which makes it even more useful than just a pile of dumb data. Just to mention some pointers which will help to understand why CDS framework is more useful:
- CDS artifacts are present and execute on database(HANA or other) layer. This strategy is called code push down where Application layer logic can be easily moved to Database layer for execution. This has many performance advantages if used carefully.
- CDS can be assigned to authorization object and visibility can be easily controlled
- CDS view can be easily consumed by oData service
- CDS view can provide semantic information to each field which is particularly helpful when information is to be displayed on browser
- CDS can be buffered just like a transparent table
- CDS can be enabled for Search
- CDS can be used to define Data Hierarchy and relationships which is particularly helpful is navigation and drill downs
HANA is in memory database and performance capabilities can be leveraged only when calculations are done in-memory. If the business logic is fully written on the application layer, this defeats the purpose of in-memory computation. New HANA artifacts like CDS, AMDP(ABAP Managed Database Procedure), CTE(Common Table Expressions) etc. fully complement code push down and are designed for performance optimization.