AttributeError: 'Student' 對象沒有屬性 '_values'

Question

我正在嘗試使用 cassandra 並使用 Flask-CQLAlchemy 庫編寫燒瓶應用程序。 當我嘗試創建我的模型類（Student）的對象時，它給了我一個名為'Student' object has no attribute '_values' 的錯誤。 經歷了與我的錯誤相匹配的多個解決方案，但無法解決這個問題。

以下是包含python代碼的文件：

from flask import *
from flask_cqlalchemy import CQLAlchemy
app = Flask(__name__)
app.config['CASSANDRA_HOSTS'] = ['127.0.0.1']
app.config['CASSANDRA_KEYSPACE'] = "emp"

db = CQLAlchemy(app)

class Student(db.Model):
    uid = db.columns.Integer(primary_key=True)
    username = db.columns.Text(required=True)
    password = db.columns.Text()

    def __init__(self, uid, username, password):
        self.uid = uid
        self.username = username
        self.password = password

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

@app.route('/add', methods = ['POST', 'GET'])
def add():
    if request.method == 'POST':
        if not request.form['uid'] or not request.form['username'] or not request.form['password']:
            flash('Please enter all the fields', 'error')
        else:
            student1 = Student(request.form['uid'], request.form['username'], request.form['password'])
            student.save()
            return render_template("successful.html")
    else:
        abort(401)

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

這是 index.html 文件

<!DOCTYPE html>
<html lang = "en">
 <head><title>index</title></head>
 <body>
  <form action = "/add" method = "post">
   UId: <input type="text" name="uid">
   Name: <input type="text" name="username">
   Password: <input type="text" name="password">

   <input type="submit" value="Submit">
  </form> 
 </body>
</html>

錯誤日志：

 File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 2463, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 2449, in wsgi_app
    response = self.handle_exception(e)
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 1866, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 1951, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 1820, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/sudarshan/python/try/try1.py", line 31, in add
    student1 = Student.create(uid=7, username='sud', password='asdfghjkl')
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/cassandra/cqlengine/models.py", line 673, in create
    return cls.objects.create(**kwargs)
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/cassandra/cqlengine/query.py", line 981, in create
    return self.model(**kwargs) \
  File "/home/sudarshan/python/try/try1.py", line 16, in __init__
    self.uid = uid
  File "/home/sudarshan/python/try/venv/lib/python3.6/site-packages/cassandra/cqlengine/models.py", line 318, in __set__
    return instance._values[self.column.column_name].setval(value)
AttributeError: 'Student' object has no attribute '_values'
127.0.0.1 - - [17/Jan/2020 15:38:34] "GET /add?__debugger__=yes&cmd=resource&f=style.css HTTP/1.1" 200 -
127.0.0.1 - - [17/Jan/2020 15:38:34] "GET /add?__debugger__=yes&cmd=resource&f=jquery.js HTTP/1.1" 200 -
127.0.0.1 - - [17/Jan/2020 15:38:34] "GET /add?__debugger__=yes&cmd=resource&f=debugger.js HTTP/1.1" 200 -
127.0.0.1 - - [17/Jan/2020 15:38:34] "GET /add?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 200 -

Answer 1

您沒有正確使用CQLAlchemy庫。

您不需要構造函數，但需要使用create函數。 只要你的課就足夠了。 此外，您的代碼中存在語法錯誤：

student1 = Student(request.form['uid'], request.form['username'], request.form['password'])
student.save()

它應該是student1.save()而不是student.save() 。

您的模型定義將如下所示：

class Student(db.Model):
    uid = db.columns.Integer(primary_key=True)
    username = db.columns.Text(required=True)
    password = db.columns.Text()

在數據庫中創建一個條目：

student = Student.create(uid=request.form['uid'], username=request.form['username'], password=request.form['password'])
student.save()

您可以在此處的模型文檔中找到有關它的更多信息。

AttributeError: 'Student' 對象沒有屬性 '_values'

問題描述

1 個解決方案

解決方案1
2 已采納 2020-01-17 15:49:32

AttributeError: &#39;Student&#39; 對象沒有屬性 &#39;_values&#39;

問題描述

1 個解決方案

解決方案1 2 已采納 2020-01-17 15:49:32

AttributeError: 'Student' 對象沒有屬性 '_values'

解決方案1
2 已采納 2020-01-17 15:49:32