Question

我有一张名为＆＃39; Codes＆＃39;和3列：id（主要），codenumber（字符串）和激活（布尔值，默认= False）

我有一个表单，我想检查值，如果它存在，请激活== False。

我试图： myform.py：

#all imports here
class CheckForm(Form):
    some_code = StringField('Code: ',validators=[Required()])
    submit = SubmitField('Check it!')

my views.py：

#all imports here
@some.route('/sometest', methods=['GET', 'POST']
def check_function():
    form = CheckForm()
    code=form.some_code.data
    check_code = Codes.query.filter_by(code=code).first()
    if check_code.activated == False:
        check_code.activated = True
        db.session.add(check_code)
        db.session.commit()
    elif check_code.activated == True:
        print 'Code already used'
    else:
        print 'Code not found')
return render_template('test.html')

但我收到错误：

AttributeError: 'NoneType' object has no attribute 'activated'

我正在使用flask和sqlalchemy

Answer 1

如果数据库中未找到任何结果，只需为 check_code 添加条件。

提示：在顶部处理失败条件并从函数返回时，它总是更具可读性。

def check_function():
    form = CheckForm()
    code=form.some_code.data
    check_code = Codes.query.filter_by(code=code).first()
    if not check_code:
        print 'Code not found'
        return   # You don't have to worry about that again

    if check_code.activated == True:
        print 'Code already used'
        return   # Second case is already covered

    # That's the only case left, no need for an `if` condition
    check_code.activated = True
    db.session.add(check_code)
    db.session.commit()

如何检查数据库中的现有值并进行更改？

1 个答案: