feat: implement natural language to SQL query generation and execution API.

Author: rahul-aot

backend/app/api/query.py

@@ -29,7 +29,8 @@ def query_sql(payload: SQLQueryRequest):
 
     except ValueError as exc:
         raise HTTPException(status_code=400, detail=str(exc))
-    except Exception:
+    except Exception as exc:
+        print(exc)
         raise HTTPException(
             status_code=500,
             detail="Failed to process SQL query"

backend/app/services/sql_generator.py

@@ -21,9 +21,9 @@ def generate_sql(question: str) -> Dict[str, Any]:
     schema = load_database_schema()
     formatted_schema = format_schema_for_prompt(schema)
 
-    system_prompt = f"""
+    # We move the "Expert" rules to the system_instruction parameter
+    system_instruction = f"""
 You are an expert SQL assistant.
-
 You are given a PostgreSQL database schema.
 Your task is to generate a SINGLE, READ-ONLY SQL query
 that answers the user's question.
@@ -46,18 +46,12 @@ def generate_sql(question: str) -> Dict[str, Any]:
 }}
 """
 
+    # Corrected method call for the google-genai SDK
     response = client.models.generate_content(
         model=settings.GEMINI_MODEL,
-        contents=[
-            types.Content(
-                role="user",
-                parts=[
-                    types.Part(text=system_prompt),
-                    types.Part(text=f"\nUSER QUESTION:\n{question}")
-                ]
-            )
-        ],
-        generation_config=types.GenerationConfig(
+        contents=f"USER QUESTION: {question}",
+        config=types.GenerateContentConfig(
+            system_instruction=system_instruction,
             temperature=0.1,
             response_mime_type="application/json"
         )
@@ -68,9 +62,9 @@ def generate_sql(question: str) -> Dict[str, Any]:
     try:
         data = json.loads(raw_text)
     except json.JSONDecodeError as exc:
-        raise ValueError("Gemini returned invalid JSON") from exc
+        raise ValueError(f"Gemini returned invalid JSON: {raw_text}") from exc
 
     if "sql" not in data or "explanation" not in data:
         raise ValueError("Gemini response missing required fields")
 
-    return data
+    return data