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Creating an SAP CAPM Demo Project and Working with Custom Functions Concepts in SAP CAPM – Part 3

In the previous two parts of this blog series, we discussed the different languages and notations in the Core Data Services (CDS) (An Introduction to CDS in the SAP CAPM; and Decoding CDS Query Language). In part three, we will look at how to create a simple CAPM project, implement custom functions in Cloud Application Programming Model and invoke the functions in the local host.  

The basic flow of an SAP CAPM Project: The CAPM Project is a Full-Stack application

A CAPM project is a Multi-Target application because it runs at different run times. For example, the persistence layer runs in the HANA DB run time, the service layer runs in the Node.js run time and The UX/UI layer runs in the Browser run time.

Step 1: Prerequisites for a CAPM project


Step 2: Creating a small demo CAPM Project.

Go to your project folder location in VS code/BAS terminal and execute the command in terminal “cds init <ProjectName>” (cds init customer)


In SAP BAS we can create the CAPM project through the Template option.

After executing the above command the project is created in your selected location like the below structure.

  • Create a DB file with “.cds” extension in the db folder for DB model (entities), like below .

   Ex:  data-models.cds in db folder

                SAP CAPM      

  • Create a Service file with “.cds” extension in the srv folder for service calls, like below .

Ex: custservice.cds in srv folder.

  • Execute  npm install command in the project terminal.
  • Run the application using “cds run (or) cds watch” in the project terminal.

You should now be able to see the below screen


Metadata result:


V4 Results: 


  • Create a .csv file for the temp data: Add the .csv file with dummy data like below;

  • Run again will get result like below

V4 Results: 



The Function implementation in a SAP CAPM Project

Now we will be implementing custom functions in the Cloud Application Programming Model and invoking the functions in localhost. 

Note: The custom functions are used to do additional activities in CRUD operations.

  1. Within service definitions, you can additionally specify actions and functions.
  2. In SAP CAP, we have two types of functions (Bound Functions and Unbound Functions)
  3. We Need to Create One “.JS”  file with the same name as the “.cds” in the srv folder in order to implement the custom logic.

Bound Functions

The Actions and functions can also be bound to individual entities of a service, enclosed in an additional actions block.


Note: Multi params Example

function boundedFunction(msg:String, data:String) returns String;

In the above example, we have defined the Bound function in the .cds file which is bound to the individual entity customer.

Now, implementing custom logic to Bounded functions. (The next most important step is creating a function definition in the .js file.)

The file location is: srv→ custservice.js

Run URL: 

//Without params

//With params”)

Result Data: 

Unbound Functions

 The notion of actions and functions in CDS is adopted at the service level. Here no involvement of entities.



Lets implement custom logic in custservice.js


Run URL:

// Without params

// With params



Note: From the CDS perspective, I recommend preferring unbound actions/functions. This is because these are far more straightforward to implement and invoke. Because you now know how to create custom functions and implement the custom functions in SAP CAPM, you will have no problem using the function concept and implementing custom logic in your code.



Ravi Krishna Thota is a Developer based out of Mindset’s Hyderabad office. He's been a front-end developer in the SAP space for over 3 years now and has spent the last 1 year as a NodeJS back-end developer with a strong focus on SAP Fiori. Ravi is extremely passionate about learning all things new in the SAP spectrum. When he is not working, you will usually find him hanging out with his friends or lounging in front of the TV.

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