[Python] SQLmodel & postgres could not locate a bind configured mapper for the session

I am using SQL model to create my tables and use as an ORM. I can create the tables fine but if I try any operation I get a sqlalchemy.exc.UnboundExecutionError: Could not locate a bind configured on mapper Mapper[User(user)], SQL expression or this Session. I have used SQLmodel with postgres before and never run in to this. Here is the code:

from contextlib import contextmanager
from logging import getLogger
from typing import Annotated, Generator

from fastapi import Depends, HTTPException
from opentelemetry import trace
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.orm import sessionmaker
from sqlmodel import SQLModel, Session as SQLModelSession, create_engine

from app.config import settings
# from telemetry import TracingContextManager
from app.auth.models import User
from app.orders.models import Order

logger = getLogger(__name__)
tracer = trace.get_tracer(__name__)

# Create engine with connection pooling for better performance under load
engine = create_engine(
settings.DATABASE_URL,
echo=settings.DB_ECHO, # Only enable echo in development
pool_pre_ping=True, # Check connection validity before using it
pool_recycle=3600, # Recycle connections after 1 hour
pool_size=10, # Maximum number of connections in the pool
max_overflow=20, # Maximum number of connections that can be created beyond pool_size
)

SessionLocal = None


def create_db_and_models() -> None:
"""Create database tables if they don't exist."""

try:
SQLModel.metadata.create_all(engine)
logger.info("Database tables created successfully")
except Exception as e:
logger.error(f"Error creating database tables: {e}")
raise


def get_session_local():
"""Get a new database session."""
global SessionLocal
if SessionLocal is None:
logger.info("Database session begun.")
SessionLocal = sessionmaker(class_=SQLModelSession, autoflush=False, bind=engine)
return SessionLocal


def get_session():
"""Dependency for FastAPI routes that need a database session."""
db = get_session_local()()
try:
yield db
logger.debug("Database session committed")
except SQLAlchemyError as e:
logger.error(f"Database error in request: {e}")
db.rollback()
raise HTTPException(status_code=500, detail="Database error")
except Exception as e:
logger.error(f"Unexpected error in database session: {e}")
db.rollback()
raise
finally:
logger.debug("Closing database session")
db.close()


# Dependency for FastAPI routes
DbSession = Annotated[SQLModelSession, Depends(get_session)]


if __name__ == "__main__":
create_db_and_models()


[Edit: I have tried using with Session(engine) as db too.

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