Hopefully I used the right verbiage in the question to describe the problem, but I will detail it more extensively below.

I am writing a SQL Alchemy database package that I want to then extend across different database projects. The example below would be I define the database package to have a User and Post with primitive values and then I import and extend it in another package with more features.

Although the database sets up the extended models and I am able to populate it correctly. Querying the features results in the models pointing at the original package instead of the new one. Semi-working, excerpt example below:

The following is the database package with the primitive models. Let’s say the file is models.py.

from sqlalchemy import Column, Integer, String, ForeignKey, Table
from sqlalchemy.orm import relationship, backref
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class User(Base):
    __tablename__ = "author"
    id = Column(Integer, primary_key=True)
    first_name = Column(String)
    last_name = Column(String)
    posts = relationship("model.Post", backref=backref("author"), enable_typechecks=False)

class Post(Base):
    __tablename__ = "book"
    id = Column(Integer, primary_key=True)
    user_id = Column(Integer, ForeignKey("author.author_id"))
    user = relationship("model_example.User", backref=backref("book"))
    title = Column(String)

These models would be extended in this new project, lets say the file is project1_models.py

from models import Base, User, Post
from sqlalchemy import Column, String

class User(User, Base):
    address = Column(String)

class Post(Post, Base):
    content = Column(String)

So although when I populate the database of the with project1_models.py models, the database features the correct columns, when I query Post.content or User.address I get a traceback error that the object doesn’t have that attribute and the type is models.Post instead of project1_models.Post

I am thinking this problem is happening because in the models.py I explicitly set the relationship to model.Post so SQL Alchemy is tying that relationship to models.Post instead of project1_models.Post.

My project is a little more complex than the example, so I want to avoid having to redefine the relationships every time I start a project while using my database package.