Accessing same db.session across different modules in sqlalchemy

1. Am I importing too many things? Do I need to import all the sqlalchemy tools?

Sqlalchemy doesn't have it's own coding style, you've to follow Python coding style. If you don't use any module there is no point of importing it.

I don't see this has been used from sqlalchemy.orm import relationship, backref and this should be used while defining models, hence you don't need to import these modules.

2. Does my init constructor under class BaseAPI need to instantiate the DB session?

There is no hard rule that you've initiate session in your BaseAPI, you can even write your programme like this..

#!/usr/bin/env python

from sqlalchemy import create_engine
from sqlalchemy.orm import relationship, backref, sessionmaker
from datetime import datetime, timedelta
import notssdb.model
from base import User #importing from the module base.py -- doesn't work

engine = create_engine('sqlite:///./notssdb.db', echo=True) #in-memory sql engine 

# create a Session
Session = sessionmaker(bind=engine)
session = Session()


class BaseAPI(object):

# CREATE USER 

    def create_user(self, username, password, fullname):
        new_user = User(username, password, fullname)
        session.commit(new_user)
        print(username, password, fullname)

But it's not good practice to club your connection generation part with user manager, I would suggest you follow this way..

Note: This is just a sample code and I didn't execute this, you just have to follow this to structure your code.

First create seperate module for connection management, may be like connection_manager.py with the below content.

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

engine = create_engine('sqlite:///./notssdb.db', echo=True)

# create a Session
Session = sessionmaker(bind=engine)

class SessionManager(object):
    def __init__(self):
        self.session = Session()

And the create your user_manger.py and import your SessionManager here.

from base import User # this is your User model
from connection_manager import SessionManager

class UserManager(SessionManager):

    def create_user(self, username, password, fullname):
        new_user = User(username, password, fullname)
        self.session.commit(new_user)
        print(username, password, fullname)

    def delete_user(self, *args):
        pass # your code

This way you can make your code cleaner.