Issue
I’m using the declarative Base in flask_sqlalchemy. In my database.py file I have the following:
from sqlalchemy import create_engine
# from sqlalchemy.orm import scoped_session, sessionmaker
# from sqlalchemy.ext.declarative import declarative_base
# from flask_sqlalchemy import SQLAlchemy
# engine = create_engine("postgresql://postgres:@localhost/video_comparisons", convert_unicode=True)
# db_session = scoped_session(sessionmaker(autocommit=False,
# autoflush=False,
# bind=engine))
# Base = declarative_base()
# Base.query = db_session.query_property()
# Session = sessionmaker(bind = engine)
# db = SQLAlchemy()
# def init_db():
# # import all modules here that might define models so that
# # they will be registered properly on the metadata. Otherwise
# # you will have to import them first before calling init_db()
# import yourapplication.models
# Base.metadata.create_all(bind=engine)
Now, each of my models imports the Base object from database.py. This avoids circular imports.
Next, I’m trying to wire up the Flask migration module, which should work like this:
db = SQLAlchemy(app)
migrate = Migrate(app, db)
manager = Manager(app)
manager.add_command('db', MigrateCommand)
As you can see, I need to pass db into the Migrate constructor. But I don’t have a db object, because I’m using the declarative Base, not creating it with db = SQLAlchemy(app).
What’s the best way to do this? In the docs, I can’t see how to connect the Migrate object to the database with this syntax.
Thanks,
Louise
Solution
You have to import the db object from database.py 🙂
Answered By – Louise
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