🚀 Using SAP Build Code + Joule with /cap-gen-app for CAP Development

🧠 What is Joule?

Joule is SAP’s generative AI assistant integrated into SAP Build Code and Business Application Studio (BAS). It helps developers build full-stack apps using natural language prompts and streamlines development tasks like data modeling, service generation, and deployment.

🛠️ Step-by-Step: Use /cap-gen-app in Joule

✅ 1. Prepare Your Environment

In BAS, launch a SAP Cloud Business Application dev space with:

• CAP Tools enabled
• Optional: HANA DB Integration and Fiori Tools

💬 2. Run /cap-gen-app: Prompt in Joule

Open Joule from the BAS sidebar and enter:

/cap-gen-app:
Create a CAP model for an online course platform.

Entities:
- Course: title, description, duration, category, instructor (1-to-1)
- Instructor: name, email, department, expertise
- Student: name, email, enrollment date
- Enrollment: student (1-to-1), course (1-to-1), status, enrollment date

Generate 5 sample records for each entity.
        

⚙️ 3. What Joule Will Do

Joule will automatically:

• Create a complete CAP project with folder structure
• Define CDS files for all entities and relationships
• Generate mock/sample data
• Set up a CAP service layer with CRUD logic
• Optionally scaffold deployment files for HANA or SQLite
• Optionally generate a basic Fiori app UI if prompted later

🚀 4. Deployment (Manual or One-Click)

You can now deploy using the terminal or BAS UI:

cds deploy --to hana
cf push
        

Or use right-click > Deploy options from BAS if your environment is connected to SAP BTP.

💡 Benefits of Using /cap-gen-app

Feature Value Speed Generate end-to-end CAP projects in seconds Clarity Describe your domain in plain English—Joule handles the technical part Best Practices Outputs clean, production-ready CDS and CAP code HANA Ready Supports .hdbcds deployment and BTP-native app architecture

Here’s a fully generated example CAP project structure and code based on the /cap-gen-app prompt for the online course platform domain.

✅ Joule Availability: BAS vs. Build Code

• SAP Build Code is essentially an enhanced version of BAS, bundled with Joule and preconfigured dev spaces for CAP/Fiori development.
• If you're using a standard BAS dev space (like the older “SAP Fiori” or “Basic” spaces): Joule will not be available.
• If you're using BAS under the SAP Build Code plan or preconfigured dev space, you’ll get:

🔍 Joule Access – SAP Business Application Studio (BAS) vs. SAP Build Code

ℹ️ Note: Joule is available in SAP Business Application Studio (BAS) only when SAP Build Code is enabled within it.

Example CAP Project: Online Course Platform

1. Project structure (simplified)

/course-platform
│
├── package.json
├── cds-config.json
├── srv/
│   └── cat-service.cds
├── db/
│   ├── data/
│   │   ├── courses.csv
│   │   ├── instructors.csv
│   │   ├── students.csv
│   │   └── enrollments.csv
│   └── schema.cds
└── README.md
        

2. CDS Model (db/schema.cds)

namespace courseplatform;

entity Course {
  key ID        : UUID;
  title        : String(100);
  description  : String(500);
  duration     : Integer;       // duration in minutes
  category     : String(50);
  instructor   : Association to Instructor;
}

entity Instructor {
  key ID        : UUID;
  name         : String(100);
  email        : String(100);
  department   : String(50);
  expertise    : String(200);
}

entity Student {
  key ID        : UUID;
  name         : String(100);
  email        : String(100);
  enrollmentDate : Date;
}

entity Enrollment {
  key ID        : UUID;
  student      : Association to Student;
  course       : Association to Course;
  status       : String(30);
  enrollmentDate : Date;
}
        

3. Service Definition (srv/cat-service.cds)

using { courseplatform as cp } from '../db/schema';

service CourseService {
  entity Courses     as projection on cp.Course;
  entity Instructors as projection on cp.Instructor;
  entity Students    as projection on cp.Student;
  entity Enrollments as projection on cp.Enrollment;
}
        

4. Sample Data (CSV files in db/data)

courses.csv

ID,title,description,duration,category,instructor_ID
1,Introduction to AI,Learn the basics of AI,120,Technology,101
2,Advanced JavaScript,Deep dive into JS,180,Programming,102
3,Project Management Essentials,Manage projects efficiently,90,Business,103
4,Creative Writing Workshop,Enhance your writing skills,60,Arts,104
5,Data Science 101,Intro to data science,150,Technology,101
        

instructors.csv

ID,name,email,department,expertise
101,Dr. Alice Smith,alice.smith@example.com,Technology,Artificial Intelligence
102,John Doe,john.doe@example.com,Programming,JavaScript, TypeScript
103,Mary Johnson,mary.johnson@example.com,Business,Project Management
104,Laura White,laura.white@example.com,Arts,Creative Writing
105,Mark Lee,mark.lee@example.com,Technology,Data Science
        

students.csv

ID,name,email,enrollmentDate
201,Kevin Brown,kevin.brown@example.com,2024-01-10
202,Sarah Wilson,sarah.wilson@example.com,2024-02-15
203,Michael Green,michael.green@example.com,2024-03-20
204,Emma Davis,emma.davis@example.com,2024-04-05
205,Oliver Miller,oliver.miller@example.com,2024-04-25
        

enrollments.csv

ID,student_ID,course_ID,status,enrollmentDate
301,201,1,Active,2024-01-12
302,202,2,Completed,2024-02-20
303,203,3,Active,2024-03-25
304,204,4,Pending,2024-04-07
305,205,5,Active,2024-04-27
        

Disclaimer: This article is intended for quick learning and introductory purposes only. For complete and detailed information, please refer to the official SAP documentation and resources.