Lecture Notes on Implementing Entity Set and Entity Type for Items

Introduction

• Discussion on implementing and testing item entity sets and types.
• Previous implementation discussed was for header entity set.

Error Handling

• Initial attempt to access item results in an error: "method is not implemented."
• Identified methods to implement for handling multiple and single entries.

Backend Implementation Steps

1. Access Backend System

   • Navigate to the method section and check inherited methods.
   • Look for item entity set get entities method.

2. Method Redefinition

   • Right-click on the method and select "Redefine."
   • Activate the method after redefining.

3. Code Implementation

   • Remove commented lines of code.
   • Execute the SQL command:

     SELECT * FROM VBRP INTO TABLE ET  
     

     • Limit results to 13 records.
   • Perform syntax check and activate the code.

4. Testing in Frontend

   • Test the implementation in the frontend.
   • Verify that data is now available (previous error resolved):
     • Displays item details including billing number and item number.

5. Data Format Testing

   • Test JSON format output using URL query:
     • Append ?format=json to the request URL.

6. Count Functionality

   • Count of entries should return 13 (hard coded).
   • Test functionality to read a single entry using primary key.

7. Backend Implementation for Single Entry

   • Navigate back to backend, redefine get entity method.
   • Generate code and remove unnecessary sections.
   • Read key from the table:

     READ TABLE ITKEY_TAB INTO LS_KEY_TAB  
     

   • Assign values to local variables for processing.

8. Select Logic

   • Check if primary key values are not initial.
   • Execute SQL command for single entry:

     SELECT SINGLE * FROM VBRP INTO ET  
     WHERE VBELN = LV_VBELN AND POSNR = LV_POSNR  
     

   • Perform syntax check and activate the method.

Frontend Testing for Single Entry

• Execute the corrected single entry request.
• Verify successful retrieval of one entry (details of VBELN and item).

Conclusion

• Key Points:
  • Multiple selects require redefining get entity set method.
  • Single entity retrieval requires redefining get entity method.
• Completion of steps 7 and 8 for item entity type and set implementation.