Работа над простым веб-приложением, которое должно возвращать «Привет, (имя извлечено из базы данных)». Он говорит, что the object has no attribute for 'name' даже если имя указано как атрибут в классе. Не могу понять, почему он думает, что его там нет (если я не понимаю ошибку)?
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app=Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres@localhost:5432/example'
db = SQLAlchemy(app)
# initalizes the class/table
class Person(db.Model):
__tablename__ = 'persons'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(), nullable=False)
db.create_all()
@app.route('/')
def index():
person = Person.query.first()
return 'Hello ' + person.name
Ошибка:
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app
response = self.full_dispatch_request()
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
raise value
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
rv = self.dispatch_request()
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/Users/ZEMEL/Dropbox (Personal)/Code/hello/flask-hello-app.py", line 20, in index
return 'Hello ' + person.name
AttributeError: 'NoneType' object has no attribute 'name'