我正在尝试通过一种烧瓶形式对数据库模型进行多次更新。本质上，我想显示测试的问题，然后让用户输入测试的答案，然后获取所有单独的响应并更新下面列出的每个对应的db.Model。

我现在所拥有的是：

表格：

class InputStudentTestForm(flaskForm):
    answer = StringField('Answer',validators=[DataRequired()])
    submit = SubmitField('Submit Answers')

页面：

{% extends "base.html" %}

{% block content %}
  <h1>{{ test.name }}</h1>
  <form action="" method="post" >
    {{ form.hidden_tag() }}
      {% for q in questions %}
      <p>
        {{ q.text }} <br>
        {{ form.answer }}
      </p>

      {% endfor %}
      <p>
        {{ form.submit() }}
      </p>
  </form>

{% endblock %}

路由：

@app.route('/input_answer/<testname>',methods=['GET','POST'])
def input_test_answer(testname):
    test = Test.query.filter_by(name=testname).first_or_404()
    questions = test.questions.all()
    form = InputStudentTestForm()
    if form.validate_on_submit():
        i = 0
        for value in form.data:
            q = questions[i]
            a = Student_Answers(current_user,test,q)
            a.add_response(value)
            db.session.add(a)
            db.session.commit()
            i = i + 1
        flash('You have just added new test responses')
        return redirect(url_for('index'))

    return render_template('input_test_answers.html',test=test,questions=questions,form=form)

型号：

class Student_Answers(db.Model):

    user_id = db.Column(db.Integer,db.ForeignKey('user.id'),nullable=True,primary_key=True)
    test_id = db.Column(db.Integer,db.ForeignKey('test.id'),primary_key=True)
    question_id = db.Column(db.Integer,db.ForeignKey('question.id'),primary_key=True)
    student_option = db.Column(db.String(1))

    db.UniqueConstraint('user_id','test_id','question_id')
    db.relationship('User',uselist=False,backref='student_answers',lazy='dynamic')
    db.relationship('Test',lazy='dynamic')
    db.relationship('Question',lazy='dynamic')

    def add_response(self,answer):
        if not self.is_response(answer):
            self.student_option = answer

    def remove_response(self,answer):
        if self.is_response(answer):
            self.student_option = ''

    def is_response(self,answer):
        return self.student_option == answer

    def __init__(self,user,question):
        self.user_id = user.id
        self.test_id = test.id
        self.question_id = question.id

    def __repr__(self):
        return '<Student_Answer {}>'.format(self.student_option)

但是当用户提交数据时，我收到一个唯一的约束失败，因为Student_Answers正在使用参数（1,1,1'answer'）更新。

我认为失败的原因是学生回答必须是单个字符，但是我不确定从form.data字符串'answer'的位置。任何帮助将是巨大的！谢谢。

编辑：我正在尝试实现动态表单方法，并出现UnboundField错误。这是更新的代码：

表格：

def DynamicTestForm(questions,*args,**kwargs):
    class TestForm(flaskForm):
        pass

    for name,value in questions.items():
        setattr(TestForm,name,value)

    return TestForm(*args,**kwargs)

路线：

def input_test_answer(testname):
    test = Test.query.filter_by(name=testname).first_or_404()
    questions = test.questions.all()
    questions_as_field = {}
    for q in questions:
        p = field.SelectField('{}' .format(q.text),choices=[('A','A'),('B','B'),('C','C'),('D','D')],validators=[DataRequired()])
        questions_as_field.update(p)

    form = DynamicTestForm(questions_as_field)
    if form.validate_on_submit():
        i = 0
        for value in form.data.values():
            a = Student_Answers.query.filter_by(user_id=current_user.id,test_id=test.id,question_id=q.id).one()
            if not a.is_response(str(value)):
                a.student_option = str(value)
            i = i + 1
        db.session.commit()
        flash('You have just added new test responses')
        return redirect(url_for('user',username=current_user.name))

和页面：

{% extends "base.html" %}

{% block content %}
  <h1>{{ test.name }}</h1>
  <form action="" method="post" >
    {{ form.hidden_tag() }}
      {% for field in form %}
      <p>
        {{ field.label }} <br>
        {{ field() }}
      </p>

      {% endfor %}
      <p>
        {{ form.submit() }}
      </p>
  </form>

{% endblock %}

但是在这一点上，我收到了UnboundField错误，但我不确定为什么。