app/database.py

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from app.config import setting

SQLALCHEMY_DATABASE_URL=f"postgresql://{setting.database_username}:{setting.database_password}@{setting.database_hostname}:{setting.database_port}/{setting.database_name}"
engine = create_engine(SQLALCHEMY_DATABASE_URL)
SessionMaker = sessionmaker(autoflush=False,autocommit=False,bind=engine)

Base = declarative_base()

def get_db():
    db =  SessionMaker()
    try:
        yield db
    finally:
        db.close()