无法使用FLASK + SQLALCHEMY将数据插入Mysql [英] Unable to insert data into Mysql Using FLASK+SQLALCHEMY

问题描述

我用html创建了一个表单，其中包含一些基本信息，例如网站，链接，名称，姓氏，电子邮件和价格.我正在尝试从html表单向我的sql数据库添加新列.

I have created a form in html with some basic information like Website, Link, Name, Last_name, email and price. I am trying to add new columns into my sql database from the html forms.

##以这种方式执行时，效果很好:

##When I do it in this way it works fine:

 from flask import Flask
 from flask_sqlalchemy import SQLAlchemy

 app=Flask(__name__)
 app.config['SQLALCHEMY_DATABASE_URI']='mysql://root:password@localhost/db_name'
 db=SQLAlchemy(app)

 class Feedback(db.Model):
      __tablename__='user'
      website=db.Column('website',db.String(20))
      link=db.Column('link',db.String(200))
      name=db.Column('name',db.String(20),primary_key=True)
      l_name=db.Column('l_name',db.String(20))
      email_=db.Column('email_',db.String(40))
      price=db.Column('price',db.Integer)

      def __init__(self,a,b,c,d,e,f):
           self.website=a
           self.link=b
           self.name=c
           self.l_name=d
           self.email_=e
           self.price=f

a=''1''
b='Name'
c='n'
d='k'
e='j'
f=10
data=Feedback(a,b,c,d,e,f)
db.session.add(data)
db.session.commit()

##当我尝试使用HTML表单中的值执行相同操作时，出现操作错误

#When I try to do the same thing with the values from the HTML form I get an Operational Error

 from flask import Flask,render_template,request,redirect
 from flask_sqlalchemy import SQLAlchemy

 app=Flask(__name__)

 app.config['SQLALCHEMY_DATABASE_URI']='mysql://root:password@localhost/db_name'

 db=SQLAlchemy(app)

 class Feedback(db.Model):
       __tablename__='user'
       website=db.Column('website',db.String(20))
       link=db.Column('link',db.String(200))
       name=db.Column('name',db.String(20),primary_key=True)
       l_name=db.Column('l_name',db.String(20))
       email_=db.Column('email_',db.String(40))
       price=db.Column('price',db.Integer)

       def __init__(self,a,b,c,d,e,f):
          self.website=a
          self.link=b
          self.name=c
          self.l_name=d
          self.email_=e
          self.price=f


  @app.route('/',methods=['GET','POST'])
  def index():
      if request.method=='POST':
      #fetch the data
           userDetails=request.form
           a=userDetails['website']
           b=userDetails['link']
           c=userDetails['name']
           d=userDetails['last_name']
           e=userDetails['email']
           f=userDetails['price']
           data=Feedback(a,b,c,d,e,f)
           db.session.add(data)
           db.session.commit()
    
           return ('Done')
      return render_template('atlas_tracker.html')

  if __name__=='__main__':
      app.run()

这是我的错误消息:

   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1246, in _execute_context
   cursor, statement, parameters, context
   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\default.py", line 588, in do_execute
cursor.execute(statement, parameters)
sqlite3.OperationalError: no such table: user

The above exception was the direct cause of the following exception:

 Traceback (most recent call last):
  File "C:\Users\nitin\anaconda3\lib\site-packages\flask\app.py", line 2446, in wsgi_app
response = self.full_dispatch_request()
   File "C:\Users\nitin\anaconda3\lib\site-packages\flask\app.py", line 1951, in full_dispatch_request
   rv = self.handle_user_exception(e)
  File "C:\Users\nitin\anaconda3\lib\site-packages\flask\app.py", line 1820, in handle_user_exception
reraise(exc_type, exc_value, tb)
   File "C:\Users\nitin\anaconda3\lib\site-packages\flask\_compat.py", line 39, in reraise
raise value
   File "C:\Users\nitin\anaconda3\lib\site-packages\flask\app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
   File "C:\Users\nitin\anaconda3\lib\site-packages\flask\app.py", line 1935, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
  File "C:\Users\nitin\Repositories\Projects\Flipkart and Amazon Price Tracker\app.py", line 41, in index
  db.session.commit()
  File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\scoping.py", line 162, in do
return getattr(self.registry(), name)(*args, **kwargs)
 File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\session.py", line 1036, in commit
self.transaction.commit()
  File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\session.py", line 503, in commit
self._prepare_impl()
  File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\session.py", line 482, in _prepare_impl
self.session.flush()
 File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\session.py", line 2479, in flush
self._flush(objects)
 File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\session.py", line 2617, in _flush
transaction.rollback(_capture_exception=True)
  File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\util\langhelpers.py", line 68, in __exit__
compat.reraise(exc_type, exc_value, exc_tb)
   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\util\compat.py", line 153, in reraise
raise value
   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\session.py", line 2577, in _flush
flush_context.execute()
    File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\unitofwork.py", line 422, in execute
rec.execute(self)
   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\unitofwork.py", line 589, in execute
uow,
    File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\persistence.py", line 245, in save_obj
insert,
    File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\orm\persistence.py", line 1084, in _emit_insert_statements
c = cached_connections[connection].execute(statement, multiparams)
  File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 982, in execute
return meth(self, multiparams, params)
   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\sql\elements.py", line 293, in _execute_on_connection
return connection._execute_clauseelement(self, multiparams, params)
    File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1101, in _execute_clauseelement
distilled_params,
   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1250, in _execute_context
e, statement, parameters, cursor, context
   File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1476, in _handle_dbapi_exception
util.raise_from_cause(sqlalchemy_exception, exc_info)
   File "C:\Users\nitin\anaconda3\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\nitin\anaconda3\lib\site-packages\sqlalchemy\util\compat.py", line 152, in reraise
raise value.with_traceback(tb)
  File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1246, in _execute_context
cursor, statement, parameters, context
      File "C:\Users\nitin\anaconda3\lib\site-packages\sqlalchemy\engine\default.py", line 588, in do_execute
     cursor.execute(statement, parameters)
    sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such table: user
    [SQL: INSERT INTO user (website, link, name, l_name, email_, price) VALUES (?, ?, ?, ?, ?, ?)]
    [parameters: ('Amazon', 'www.amazon.com', 'Name ', 'jjjj', '[e-mail]', '1200')]
    (Background on this error at: http://sqlalche.me/e/e3q8)
     127.0.0.1 - - [26/Jun/2020 23:30:14] "POST / HTTP/1.1" 500 -

推荐答案

尝试在您的app.py文件中添加此代码

Try to add this code in your app.py file

@app.before_first_request
def create_tables():
    db.create_all()

它将在第一次请求之前创建表

It will create tables before first request

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