Tag: flask-sqlalchemy

Best way to check if database already exists with flask-sqlalchemy, otherwise create

flask flask-sqlalchemy python sql sqlalchemy

I have a database app, and want to create the tables and database on the fly when starting the app for the first time. If the app is restarted, it should only create the database and tables if they do not exist, otherwise ignore this creation. I have a few questions. 1.) Is this a proper way of dealing with

AttributeError: ‘NoneType’ object has no attribute ’email’. Flask-sqlalchemy

attributeerror flask flask-sqlalchemy python sql

i’ve a strange problem… i do this: and gives me this problem: Who can help me?? thanks <3 Answer it means it didn’t find any users matching your filter

First row of all groups in Flask SQLAlchemy

flask-sqlalchemy postgresql python sql sqlalchemy

I want to group the database by gauge_id and then get the row having maximum time_col. This is my current code: But I am only able to get both gauge_id and time_col. When I add another column (reading), like this: it gives this error. How do I return the top row of each groups? Thanks in advance. Answer One way

ORM query many to many to one, Flask sql-alchemy

flask flask-sqlalchemy sql sqlalchemy

I have three flask-sqlalchemy-models. Books – unique entries by admin: class Book(db.Model): id = db.Column(db.Integer, primary_key=True, autoincrement=True) book_name = db.Column(db.String(20)…

Convert PostgreSQL COUNT … FILTER query to SQL Alchemy

flask-sqlalchemy postgresql sql sqlalchemy

I’m new to SQLAlchemy, and I would like to convert this PostgreSQL query: I have already tried this: Thank you in advance for your help Answer Thanks to @IljaEverilä’s comment, here is a more direct answer: (Original answer) I’m not sure if SQLAlchemy’s postgresql dialect specifically handles COUNT … FILTER, but you can accomplish the same thing using SUM and

Best practice for scaling SQL queries on joins?

flask-restx flask-sqlalchemy sql sqlalchemy

I’m writing a REST api that works with SQL and am constantly finding myself in similar situations to this one, where I need to return lists of objects with nested lists inside each object by querying over table joins. Let’s say I have a many-to-many relationship between Users and Groups. I have a User table and a Group table and

Flask SQLAlchemy query join

flask-sqlalchemy python sql sqlalchemy

I have 2 table like this: Then I try to making 2 kinds of query to get data for the relationship models. first, I make it like this: and the second one I use join statement on that: My questions are, what’s the difference in that query while in the second one I use the join statement but the result

Querying association table object directly

flask-sqlalchemy python sql sqlalchemy

I have to query the relationships directly, since I have to display them seperatly. task_user = db.Table( ‘pimpy_task_user’, db.Column(‘task_id’, db.Integer, db.ForeignKey(‘pimpy_task.id’)), …