Improvement: Optimize Fetch All Roles API (#164)

[baydre]

Description

This PR improves the /api/v1/organisations endpoint by optimizing the get_roles_for_organisation function.
Changes include:

• Remove unnecessary tuple creation and improve query efficiency.
• Enhanced error handling, ensuring a structured response for failures.
• Maintaining response format consistency as per project requirements.
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Related Issue (Link to issue ticket)

​​Closes #164

Motivation and Context

The improvement ensures:

• Faster query execution by eliminating unnecessary tuple creation.
• Better error handling, returning meaningful error messages instead of generic failures.
• Compliance with the standard API response format.

This improves overall system performance and maintainability.​

How Has This Been Tested?

• Unit Tests:

  • Tested successful retrieval of all roles (200 OK).
  • Simulated a database error to test server error handling (500 Internal Server Error).

• Manual Testing:

  • Used Postman and curl to verify API responses.

• Environment:

  • OS: Ubuntu 20.04
  • Python: 3.10
  • Database: PostgreSQL

Screenshots (if appropriate - Postman, etc):

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Types of changes

• Improvement Feature (enhances an existing feature)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
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Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Notes for Reviewers

• Please verify the performance improvement in the updated query execution.
• Check error handling updates to confirm structured responses.

🚀 Looking forward to feedback! 😃

[samuelogboye]

LGTM.

But hope this is not your grading PR?