👀 Views: 476 💬 Answers: 1 📅 Created: 2025-06-06

fastapi sqlalchemy sqlite integrityerror Python

I'm working on a FastAPI application (version 0.68.0) that uses SQLAlchemy (version 1.4.22) for database interactions. While trying to create a new user in my database, I'm working with an `IntegrityError` that states `UNIQUE constraint failed: users.email`. This behavior occurs even when I ensure that the email being inserted is unique. Here’s the function that handles the user creation: ```python from fastapi import FastAPI, HTTPException from sqlalchemy.orm import Session from models import User from database import SessionLocal, engine app = FastAPI() @app.post("/users/") def create_user(user: UserCreate, db: Session = Depends(get_db)): db_user = db.query(User).filter(User.email == user.email).first() if db_user: raise HTTPException(status_code=400, detail="Email already registered") new_user = User(**user.dict()) db.add(new_user) db.commit() # This line raises the IntegrityError db.refresh(new_user) # Refreshing the instance return new_user ``` I've verified that the email is unique right before the commit operation, and I've also tried running the user creation in a transaction context to see if it makes a difference, but the behavior continues. My database is SQLite for local development. I’ve added logging to monitor the emails being checked and committed, and they seem correct. However, I still receive the same behavior every time I try to insert a user with a unique email. I even attempted to clear the database and restart the FastAPI server, but the scenario didn't resolve. Any insights into why this `IntegrityError` might be occurring? I suspect it could be related to session management or how the database connection is handled, but I’m not sure what to investigate next.