我正在通过以下教程构建基本的Flask应用程序来学习数据库:https://www.tutorialspoint.com/flask/flask_sqlalchemy.htm我目前正处于需要连接到SQLITE3数据库的位置通过SQLAlchemy.说实话,它并不顺利.我收到此错误:NameError:未定义全局名称'flash'

这是我的app.py.

#!/usr/bin/python

from flask import Flask, render_template, json, request
from flask_sqlalchemy import SQLAlchemy
import sqlite3



cOnn= sqlite3.connect('test.db')




app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///students.sqlite3'
db = SQLAlchemy(app)


class Students(db.Model):
    id = db.Column('student_id',db.Integer, primary_key=True)
    name = db.Column(db.String(80), unique=True)

    def __init__(self, name, id):
        self.name = name
        self.id = id

    def __repr__(self):
        return '' % self.name


db.create_all()


@app.route("/")
def main():
    return render_template('index.html')




@app.route('/new', methods = ['GET', 'POST'])
def new():
   if request.method == 'POST':
      if not request.form['name'] or not request.form['id']:
         flash('Please enter all the fields', 'error')
      else:
         student = Students(request.form['name'], request.form['id'])
         db.session.add(student)
         db.session.commit()

         flash('Record was successfully added')
         return redirect(url_for('show_all'))
   return render_template('new.html')



@app.route("/admin")
def show_all():
   return render_template('show_all.html', students = students.query.all() )



    # create user code will be here !!


if __name__ == "__main__":
    app.run(debug=True)

的index.html

    


    

    






    

        

            
            
Python Flask App
        

        

            
Attendance App
            

            
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show_all.html

    
    
       
       

          

             Comments - Flask 
                SQLAlchemy example
          

          

          {%- for message in get_flashed_messages() %}
             {{ message }}
          {%- endfor %}

          
Students (Add Student
             )

          
                {% for student in students %}
                   

                {% endfor %}
             

             

                

                   
Name
                   
Id
                
             

             

                      
{{ student.name }}
                      
{{ student.id }}
          

       
    

**new.html**



   

      
Attendance
      


      {%- for category, message in get_flashed_messages(with_categories = true) %}
         

            {{ message }}
         
      {%- endfor %}

      
         Name

         

         Id Number

         

         

      

   

问题:

我不知道连接是否有效,即使错误得到修复,NameError因为它是我的第一个,起初我尝试使用MySQL但不推荐使用flask.ext.mysql,所以我尝试切换到SQLAlchemy和SQLite3 .对于像我这样的新手,我感激不尽.谢谢!

添加from flask import flash到您的代码中.所有HTML文件都与问题无关.