Flask connection mysql, implement page login

主要代码：
from flask import Flask,request,g,session,flash,redirect,url_for,render_template
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://root:12345678@localhost/mydb'
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
class User(db.Model):
    class User(db.Model):
        __tablename__ = 'user'
        id = db.Column(db.Integer, primary_key=True, autoincrement=True, nullable=False)
        name = db.Column(db.String(20), nullable=False)
        password = db.Column(db.String(30), nullable=False)
    def __repr__(self):
        return 'the User: S%'% the self.name 
db.create_all () 

@ app.route ( '/ Login', Methods = [ 'the POST', 'the GET']) 
DEF Login (): 
    IF request.method == ' the POST ': 
        name = Request.Form [' User '] 
        password = Request.Form [' the passwd '] 
        from SQLAlchemy # import and_ introduced and_ query 
        cursor = User.query.filter (and_ (User.name == name, User . .password == password)) first ( ) # query the database, first () returns the first result of a query, if there is no return None 
        IF iS not the Cursor None: 
            the session [ 'the User'] = name 
            Flash ( 'the Login successfully! ') 
            return the redirect (the url_for (' index '), 302) 
        the else: 
            Flash ('! SUCH User No ',' error ')
            return redirect(url_for('login'),302)
    else:
        return render_template('login.html')

@app.route('/')
def index():
    if 'user' in session:
        return render_template('hello.html', name=session['user'])
    else:
        return redirect(url_for('login'),302)
@app.route('/logout')
def logout():
    session.pop('user', None)
    return redirect(url_for('login'), 302)
app.secret_key = '12345678'
if __name__ == '__main__':
    app.run(host='127.0.0.1', debug=True)

页面HTML：

{% extends "layout.html" %}
{% block body %}
<form name="login" action="/login" method="post">
    Username: <input type="text" name="user" /><br>
    Password: <input type="password" name="passwd" /><br>
    <input type="submit" value="Submit" />
</form>
{% endblock %}