database.py

import os
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

# sqlite connection
#SQLALCHEMY_DATABASE_URL = "sqlite:///./todos.db"

# postgres connection
SQLALCHEMY_DATABASE_URL = "postgresql://postgres:12345@localhost/postgres"

# postgres connection  heroku

"""HOST_DB_HEROKU = os.environ.get('HOST_DB_HEROKU')
DB_HEROKU = os.environ.get('DB_HEROKU')
DB_USER_HEROKU = os.environ.get('DB_USER_HEROKU')
DB_PASSWORD_HEROKU = os.environ.get('DB_PASSWORD_HEROKU')

SQLALCHEMY_DATABASE_URL = "postgresql://"+DB_USER_HEROKU+":"+DB_PASSWORD_HEROKU +"@"+HOST_DB_HEROKU+":5432/"+DB_HEROKU+""
"""


# mysql connection
#SQLALCHEMY_DATABASE_URL = "mysql+pymysql://root:test1234!@127.0.0.1:3306/todoapp"

engine = create_engine(
    #solo para sqlite
    #SQLALCHEMY_DATABASE_URL, connect_args = {"check_same_thread": False}
   
    SQLALCHEMY_DATABASE_URL
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()