我之前已经尝试过了，但仍然有效，现在我又做了一次，但是没有成功。我使用虚拟环境。
db文件与init和放在同一目录中models。db.create_all()导入db后，我还在python shell中执行了。我执行时发生错误Students.query.all()。我现在真的很困惑。我将代码与现有项目进行了比较，这是相同的。我不明白为什么它不起作用。
Traceback (most recent call last):
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\base.py", line 1246, in _execute_context
cursor, statement, parameters, context
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\default.py", line 581, in do_execute
cursor.execute(statement, parameters)
sqlite3.OperationalError: no such table: students
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\orm\query.py", line 3211, in all
return list(self)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\orm\query.py", line 3367, in __iter__
return self._execute_and_instances(context)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\orm\query.py", line 3392, in _execute_and_instances
result = conn.execute(querycontext.statement, self._params)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\base.py", line 982, in execute
return meth(self, multiparams, params)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\sql\elements.py", line 287, in _execute_on_connection
return connection._execute_clauseelement(self, multiparams, params)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\base.py", line 1101, in _execute_clauseelement
distilled_params,
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\base.py", line 1250, in _execute_context
e, statement, parameters, cursor, context
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\base.py", line 1476, in _handle_dbapi_exception
util.raise_from_cause(sqlalchemy_exception, exc_info)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\util\compat.py", line 398, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb, cause=cause)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\util\compat.py", line 152, in reraise
raise value.with_traceback(tb)
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\base.py", line 1246, in _execute_context
cursor, statement, parameters, context
File "C:\Users\Martin\Desktop\regtry\venv\lib\site-packages\sqlalchemy\engine\default.py", line 581, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such table: students
[SQL: SELECT students.id AS students_id, students.last_name AS students_last_name, students.college AS students_college, students.email AS students_email
FROM students]
(Background on this error at: http://sqlalche.me/e/e3q8)
_ _初始化_ _.py：
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
main = Flask(__name__)
main.config['SECRET_KEY'] = '3bce79429ad6b79670e4e800fb4a57b9'
main.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///site.db'
db = SQLAlchemy(main)
from reg import routes
models.py：
from reg import db
class Students(db.Model):
id = db.Column(db.Integer, primary_key=True)
last_name = db.Column(db.String(60), nullable=False)
college = db.Column(db.String(60), nullable=False)
email = db.Column(db.String(120), unique=True, nullable=False)
def __repr__(self):
return f"Student('{self.last_name}','{self.college}','{self.email}')"
在shell中，在执行之前导入database和第models一个db.create_all()。显然，创建数据库而不导入模型时会发生错误。
我的错误是：
>>from APPFOLDER import db
>>db.create_all()
>>from APPFOLDER.models import MODELNAME
>>MODELNAME.query.all()
***ERROR MSG***
您应该做什么：
>>from APPFOLDER import db
>>from APPFOLDER.models import MODELNAME
>>db.create_all()
>>MODELNAME.query.all()
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我来说两句