Hello World program - SAP CDS programming - a brief

While a traditional "Hello, World!" program focuses on outputting text, SAP CDS focuses on defining data models. So, instead of printing "Hello, World!", we'll create a simple CDS view that fetches data from a database table.

Here's a basic example to get you started:

@AbapCatalog.sqlViewName: 'ZHELLO_WORLD'  define view ZHello_World as select from spfli {       carrid,      connid,      cityfrom,      cityto  } where carrid = 'LH';  

Explanation:

• @AbapCatalog.sqlViewName: 'ZHELLO_WORLD': This line defines the name of the SQL view that will be created in the database. In SAP systems, it's convention to start custom objects with "Z".
• define view ZHello_World: This line defines a CDS view named ZHello_World.
• select from spfli: This line specifies that the data will be selected from the database table spfli (a standard SAP table containing flight connection information).
• { carrid, connid, cityfrom, cityto }: This line selects the fields carrid, connid, cityfrom, and cityto from the spfli table.
• where carrid = 'LH': This line filters the data to only include flights with the airline code 'LH' (Lufthansa).

To run this code:

1. Access an SAP system: You'll need access to an SAP system with ABAP Development Tools (ADT) installed.
2. Create a new ABAP package: Create a new package in your SAP system to store your development objects.
3. Create a new CDS view: In ADT, create a new CDS view file within your package.
4. Copy and paste the code: Copy and paste the code above into the CDS view file.
5. Activate the CDS view: Save and activate the CDS view. This will create the corresponding SQL view in the database.
6. Preview the data: In ADT, you can preview the data by right-clicking on the CDS view and selecting "Open Data Preview". This will show you the data that is fetched by the view.

This example demonstrates the basic syntax of CDS views and how to select data from a database table. You can build upon this foundation to create more complex CDS views with joins, aggregations, and other features.

This is just a starting point for learning SAP CDS programming. There are many other concepts and features to explore, such as:

• Annotations: Annotations are used to add metadata to CDS views, which can be used for various purposes, such as defining OData services or UI elements.
• Associations: Associations define relationships between different CDS views.
• Functions and expressions: CDS views can include functions and expressions to perform calculations and manipulate data.

I recommend exploring the following resources to learn more about SAP CDS programming:

• SAP Help Portal: The SAP Help Portal provides comprehensive documentation on CDS views.
• SAP Community Network: The SAP Community Network is a great place to ask questions and get help from other SAP developers.
• OpenSAP: OpenSAP offers free online courses on various SAP topics, including CDS views.

By studying these resources and practicing with your own examples, you can gain a deeper understanding of SAP CDS programming and its capabilities.