demo-backend/document-service/app/services/dropdown_service.py

# --- Library Imports ---
from sqlalchemy.exc import SQLAlchemyError
from fastapi import HTTPException, status
from sqlalchemy import text

# --- User Imports ---
from app.schema.response_schema import ResponseSchema

class DocumentDropdownService:
    @staticmethod
    async def _fetch_data(query: str, success_message: str, db) -> dict:
        """
        Fetch data from the database.

        Parameters:
        - query: SQL query string
        - success_message: Success message string
        - db: Database session

        Returns:
        - ResponseSchema: Response object containing fetched data
        """
        try:
            # Execute the SQL query
            result = db.execute(text(query))
            column_names = result.keys()
            data = [dict(zip(column_names, row)) for row in result.fetchall()]

            return ResponseSchema(
                status=200,
                message=success_message,
                success=True,
                data=data,
            )
        except SQLAlchemyError as e:
            db.rollback()
            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(e))
        
    @staticmethod
    async def get_loanTypes(db):
        """
        Fetch document status data.

        Parameters:
        - db: Database session

        Returns:
        - ResponseSchema: Response object containing document status data
        """
        return await DocumentDropdownService._fetch_data(
            'SELECT * FROM "DocumentStatuses";', "Document status fetched successfully!", db
        )