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SAP Developer Challenge - SAP Cloud Application Programming Model (Week 1)

Please note that this challenge is closed. The deadline for receiving a badge upon successful completion has passed. Check out this new challenge for the month of August.
Welcome to the first week of this month's SAP Developer Challenge. This week we are going to learn how to get started with the SAP Cloud Application Programming Model (CAP) and domain modeling. If you haven't read the announcement blog post for this challenge, please head over and do so.

The Challenge

The objective this week is to build a CAP service, that can track golf rounds. Yes, you read that right – golf rounds ️🏌🏽‍. This is a completely artificial scenario that we made up, but it lends itself pretty well to practice a few basic CAP features.
We have prepared a starter project (link to CodeSandbox below) that already contains the entity "Rounds" and exposes it via a service. It is your job to enrich this existing service.

This is what you have to do to successfully complete this week's challenge:
  1.  Go to the CodeSandbox and fork it. You have to have an account with CodeSandbox and be be signed in to be able to do that.
  2. Work on the project so it represents the following relationships:
        1. The service should track who entered a new round and when it was entered (hint: managed entities).
        2. A round consists of multiple holes. No hole can exists without its "parent" round (hint: compositions vs. associations).
        3. Each hole has a score, representing the number of shots it took a player to get the ball into the hole.
        4. Similarly, each hole has a par of 3, 4, or 5, representing the average amount of shots it takes a professional golfer to get the ball into the hole.
        5. Each hole consists of one or more shots. Similar to rounds and holes, no shot can exists without its "parent" hole (hint: compositions vs. associations).
        6. (Feel free to add more fields to the entities as you see fit.)
  3. Run the dev server using the predefined "dev" task. To do so, click on the little plus icon (+) to open the dev tools and click on "Tasks > dev".
  4. Wait for the server to start. Once done, click on "http://localhost:4004".
  5. Open the metadata of the "browse" service.
  6. Take a screen shot of the metadata and post it into this discussion thread. Hopefully it looks something like this (a few sections collapsed in the screen shot):




We have gathered a few helpful resources to get started. Also make sure to inspect the existing code in the starter project and try to understand what it does.

Note: If you encounter issues with your dev server not starting properly, check your cds syntax. Unfortunately, the CodeSandbox doesn't have syntax highlighting for cds and it may not provide clear error messages. One useful approach is to comment out sections of code until the server starts, then gradually uncomment to isolate the problematic line.

Good luck and happy learning!
168 REPLIES 168


@nicoschoenteich Week 1 challenge, close enough?

CAP result.png


Sweet! That looks perfect. Good job 💪

Galactic 1
Galactic 1

I think I misunderstood the 4th item But I tried it, what do you guys think?



Good job.

And yeah, score and par should be properties of the holes entity, not the shots 😉

Did you go for compositions or associations?

associations like:


entity Rounds : cuid {
holes : Association to many Holes on holes.rounds = $self;

entity Holes : cuid {
rounds: Association to Rounds;

Go with compositions instead, as shots shouldn't exists without their "parent" hole. Read more about the difference here:

Galactic 3
Galactic 3

Galactic 3
Galactic 3


Here is my submission for week 1:





Well done, did you go with a managed entity for the Rounds? Just curious why there is no "modifiedAt" and "modifiedBy"...


You're right, I completely forgot these fields... 😅. I've updated:


Tks! 😁


Galactic 2
Galactic 2

First time actually giving CAP a try. Is this it?



You bet this is it! Good job.

Galactic 3
Galactic 3

Hello, attached is the expected output. Is this appropriate for the exercise?



Galactic 4
Galactic 4

Hi Nico,

Here is my submission EDMX for Week#1's assignment, hope it is correct :).




Wises K.

Galactic 2
Galactic 2

Stellar 2
Stellar 2

Unable to open sandbox . Created a account as well.



Hm, that's not good. Can you maybe try again? Hope it was just something temporary... Where you able to fork the repository?

Galactic 3
Galactic 3



Why do we have score when wee could just see the length of the array of shots?

I think I got everything

Because we are just getting started 😉 Curious to see your implementation though!


Hi @nicoschoenteich  great idea, thanks for the post. Does this complete week 1 challenge?



Galactic 3
Galactic 3

My submission for week 1 challenge.  I added some validations using @assert annotations.

@nicoschoenteich does it look good?



Well done and good idea with add "@assert".

I'm curious, where is the annotation "CatalogService.Rounds/entered_at" coming from?

it's here, and I have added "@cds.on.insert: $now;" annotaiton on that field



Galactic 3
Galactic 3

Galactic 3
Galactic 3

Hi @nicoschoenteich ,

Here is my submission for Week 1. Thanks for the challenge.



Galactic 2
Galactic 2

My submission for week 1:



Galactic 2
Galactic 2


My submission: