Sqlalchemy db.create_all() erstellt keine Tabellen

Question

Ich befolge zurzeit this pattern, um zirkuläre Importe zu vermeiden. Dieses Muster scheint ziemlich nisch zu sein, so dass es schwierig war, eine Lösung zu finden, die googelt.

models.py

from sqlalchemy.orm import relationship 

db = SQLAlchemy() 

class Choice(db.Model): 
    id = db.Column(db.Integer, primary_key=True) 
    text = db.Column(db.String(32)) 
    votes = relationship("Vote") 

    def __init__(self, text): 
    self.text = text 

application.py

app = Flask(__name__) 
app.debug = True 

basedir = os.path.abspath(os.path.dirname(__file__)) 
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'db.sqlite3') 
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False 
db.init_app(app)  # Reinitialiez db.Model to avoid cyclical imports in models.py 

db_create.py

#!flask/bin/python 
from application import app, db 
from models import Choice 

db.init_app(app) 
db.create_all() 

db.session.add(Choice("Red")) 
db.session.add(Choice("Blue")) 
db.session.add(Choice("Green")) 

db.session.commit() 

Wenn ich separat laufen db_create.py, erhalte ich:

$ python db_create.py 
Traceback (most recent call last): 
    File "db_create.py", line 6, in <module> 
    db.create_all() 
    File "/home/ubuntu/.virtualenvs/paw-py/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 972, in create_all 
    self._execute_for_all_tables(app, bind, 'create_all') 
    File "/home/ubuntu/.virtualenvs/paw-py/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 949, in _execute_for_all_tables 
    app = self.get_app(app) 
    File "/home/ubuntu/.virtualenvs/paw-py/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 922, in get_app 
    raise RuntimeError('application not registered on db ' 
RuntimeError: application not registered on db instance and no application bound to current context 

Was soll ich tun? Was ist das beste Muster, um damit umzugehen? Ich habe sogar versucht, db.create_all() in meinem application.py nach if __name__ == '__main__' Zugabe, aber ich bin immer noch die gleichen Fehler

Answer 1

Flask-SQLAlchemy Sagen Sie immer die „aktuelle“ App mit app_context

with app.app_context(): 
    # your code here 
    db.create_all() 

ist