Entities and CDS (Core Data Services) views are both components of the ABAP programming language used in SAP systems, but they serve different purposes and have different characteristics. Here's a breakdown of their differences:
Purpose:
Entities: Entities represent individual objects or business entities, such as a customer, product, or sales order. They define the structure and attributes of an object, including its properties, relationships, and behavior.
CDS Views: CDS views are used for defining data models and virtual data structures. They provide a way to define complex queries, aggregations, joins, and calculations over one or more database tables or other CDS views.
Data Access:
Entities: Entities are mainly used for data manipulation and persistence. They provide an abstraction layer over the underlying database tables and allow you to perform CRUD (Create, Read, Update, Delete) operations on the data.
CDS Views: CDS views are primarily used for data retrieval and reporting purposes. They define a virtual table-like structure that can be queried and consumed by various applications and reporting tools.
Structure and Definition:
Entities: Entities are defined using the ABAP Object-Oriented Programming (OOP) concepts. They can have attributes, associations (relationships to other entities), and methods (behavior).
CDS Views: CDS views are defined using the ABAP CDS syntax, which is a declarative language extension of SQL. They can include fields from one or more database tables or other CDS views, along with calculated fields, aggregations, and filters.
Extensibility:
Entities: Entities can be extended and enhanced by adding new attributes, relationships, or behavior using inheritance and other OOP concepts.
CDS Views: CDS views can be extended using CDS view annotations and annotations-based extensions. You can add additional fields, filters, and calculations to an existing CDS view without modifying its original definition.
Usage:
Entities: Entities are used primarily in ABAP development for implementing business logic and data persistence, such as creating or modifying database records.
CDS Views: CDS views are used for reporting, analytics, and providing data access to external systems or applications. They can be consumed by other ABAP programs, SAP Fiori apps, or external reporting tools.
In summary, entities are used for data manipulation and persistence, while CDS views are used for defining complex data models and virtual data structures for reporting and querying purposes. Entities focus on the individual objects, while CDS views provide a broader perspective on the data landscape.
