TutorialsPoint-Flask – SQLAlchemy无法正常工作 [英] TutorialsPoint - Flask – SQLAlchemy not working

问题描述

我完成了教程要点上的所有说明(只是复制并粘贴)，但是当我尝试添加学生条目时，即它会显示添加学生"

I did all that was stated on tutorial point (just copied and pasted), but when I tried to add a student entry,i.e. ‘Add Student’ it gives

错误请求浏览器(或代理)发送了该服务器无法理解的请求.

Bad Request The browser (or proxy) sent a request that this server could not understand.

请告知本教程是否有问题.

Please advise if there is anything wrong with the tutorial.

在app.py的def new()中的这一行失败了:

It failed at this line within def new(), in app.py:

 student = students(request.form['name'], request.form['city'], request.form['addr'], request.form['pin'])

任何人对此进行标榜.请注意，本教程中充满了错别字和错误的缩进.我只是一个学生.将此关闭，我将一无所获.

Whoever is flagging this down. Note that it is the tutorial that is filled with typos and wrong indentations. I am only a student. Shut this down and I will learn nothing.

参考: http://www.tutorialspoint.com/flask/flask_sqlalchemy.htm

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

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///students.sqlite3'
app.config['SECRET_KEY'] = "random string"

db = SQLAlchemy(app)

class Students(db.Model):
    id = db.Column('student_id', db.Integer, primary_key = True)
    name = db.Column(db.String(100))
    city = db.Column(db.String(50))
    addr = db.Column(db.String(200)) 
    pin = db.Column(db.String(10))

    def __init__(self, name, city, addr,pin):
        self.name = name
        self.city = city
        self.addr = addr
        self.pin = pin

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

    @app.route('/new', methods = ['GET', 'POST'])
    def new():
        if request.method == 'POST':
            if not request.form['name'] or not request.form['city'] or not request.form['addr']:
                flash('Please enter all the fields', 'error')
        else:
            print "1";
            student = Students(request.form['name'], request.form['city'], request.form['addr'], request.form['pin'])

            print "1";
            db.session.add(student)
            print "1";
            db.session.commit()
            print "1";
            flash('Record was successfully added')
            print "=======>>>>>>>>>";
            return redirect(url_for('show_all'))
        return render_template('new.html')

if __name__ == '__main__':
    db.create_all()
    app.run(debug = True)

推荐答案

该教程在学生班级中存在缩进问题.构造函数代码应缩进一级，以使其成为学生类的一种方法.

The tutorial has an indentation problem in the student class. The constructor code should be indented one level so it becomes a method of the student class.

正确的代码:(请注意以下代码中的"def init (自身，名称，城市，地址，地址，PIN):"的缩进)

Corrected code: (note the indent of "def init(self, name, city, addr,pin):" in the code below)

class students(db.Model):
   id = db.Column('student_id', db.Integer, primary_key = True)
   name = db.Column(db.String(100))
   city = db.Column(db.String(50))
   addr = db.Column(db.String(200)) 
   pin = db.Column(db.String(10))

   def __init__(self, name, city, addr,pin):
      self.name = name
      self.city = city
      self.addr = addr
      self.pin = pin

原因是，如果该缩进不存在，python将不会将此函数视为学生类的构造函数.因此找不到具有匹配数量的参数的构造函数，从而导致错误.

The reason is, if that indent is not there, python will not see this function as a constructor of the student class. So the constructor with the matching number of arguments is not found, resulting in the error.

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