Refactor database models and schemas to allow nullable fields; update init_database function for improved initialization.

app/main.py

@@ -1,7 +1,7 @@
 import io
 
 import pandas as pd
-from db.db import db_dependency, init_database
+from db.db import Base, db_dependency, engine
 from dotenv import load_dotenv
 from fastapi import FastAPI, File, Form, UploadFile
 from pydantic import BaseModel
@@ -11,6 +11,13 @@ from services.llm_parser import InvestorProcessor
 from services.querying import QueryProcessor
 
 load_dotenv()
+
+
+def init_database():
+    """Initialize the database by creating all tables"""
+    Base.metadata.create_all(bind=engine)
+
+
 init_database()
 
 app = FastAPI()
@@ -34,7 +41,9 @@ def health():
 
 
 @app.post("/parse-csv", tags=["CSV Upload"], response_model=list[dict])
-async def parse_csv(db: db_dependency, file: UploadFile = File(...), is_investor: int = Form(...)):
+async def parse_csv(
+    db: db_dependency, file: UploadFile = File(...), is_investor: int = Form(...)
+):
     # Read uploaded CSV with pandas
     content = await file.read()
     df = pd.read_csv(io.StringIO(content.decode("utf-8")))