SQLAlchemy’s filter_by takes keyword arguments: filter_by(**kwargs) In other words, the function will allow you to give it any keyword parameter. This is why you can use any keyword that you want in your code: SQLAlchemy basically sees the arguments a dictionary of values. See the Python tutorial for more information on keyword arguments. So that … Read more
I haven’t used SQLAlchemy much so I figured I’d give it a shot. I didn’t try to use your models, I just wrote some new ones (similar enough though): likes = db.Table(‘likes’, db.Column(‘user_id’, db.Integer, db.ForeignKey(‘user.id’)), db.Column(‘post_id’, db.Integer, db.ForeignKey(‘post.id’)) ) class User(db.Model): id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String(20)) def __repr__(self): return “<User(‘%s’)>” % self.username class … Read more
Your code has the line from app.models import User in __init__.py. The problem is that app.models has from . import db. This is a circular import: __init__ tries to import User, which tries to import db, which isn’t defined until after __init__ tries to import User. To solve this, move your local app imports below … Read more
I fixed the problem with the help of the Application Factory pattern. I declare the database in a third module and configure it later in the same module in which I start the application. This results in the following imports: database.py → app.py views.py → app.py database.py → views.py There is no circular import. It … Read more
results is a tuple and I want it to be of type dict() Updated answer for SQLAlchemy 1.4: Version 1.4 has deprecated the old engine.execute() pattern and changed the way .execute() operates internally. .execute() now returns a CursorResult object with a .mappings() method: import sqlalchemy as sa # … with engine.begin() as conn: qry = … Read more
flask_sqlalchemy doesn`t allow you to use it outside of a Flask context. However, you can create models via SQLAlchemy itself. So your database.py file would look like this: from sqlalchemy import MetaData, Column, Integer, String from sqlalchemy.ext.declarative import declarative_base metadata = MetaData() Base = declarative_base(metadata=metadata) class Job(Base): __tablename__ = ‘job’ job_id = Column(Integer, primary_key=True) description … Read more
I just got done setting up a Flask app and I dealt with this kind of problem. I strongly suspect the problem here is that the instance of db that you are creating in __init__.py is unaware of the contents of models.py, including the User class. The db object in __init__.py is a totally separate … Read more
In most cases not defining a constructor in your model class gives you the correct behavior. Flask-SQLAlchemy’s base model class (which is also SQLAlchemy’s declarative base class) defines a constructor that just takes **kwargs and stores all the arguments given, so it isn’t really necessary to define a constructor. If you do need to define … Read more
The main feature of the Flask-SQLAlchemy is proper integration with Flask application – it creates and configures engine, connection and session and configures it to work with the Flask app. This setup is quite complex as we need to create the scoped session and properly handle it according to the Flask application request/response life-cycle. In … Read more