带有 SQLAlchemy 的 Flask WTForms：在数据库中存储表单时出现 UnmappedInstanceError

Question

我无法使用 Flask-SQLAlchemy 将表单存储在 sqlite3 数据库中。当我尝试存储表单时，我的 views.py 抛出以下错误。

UnmappedInstanceError: Class 'app.forms.Survey1' is not mapped

Views.py

​​>

@app.route('/survey_1/', methods=['GET','POST'])
@login_required
def survey_1():
    form = Survey1(request.form)
    if form.validate_on_submit():
        print form
    db.session.add(form)
    db.session.commit()
    return redirect(url_for('index'))
    return render_template('Survey1.html', title='Survey', form=form)

模型.py

​​>

class Survey1(db.Model):
    id = db.Column(db.Integer, primary_key = True)
    gender = db.Column(db.Integer)
    age = db.Column(db.Integer)
    education = db.Column(db.Integer)
    language = db.Column(db.String(20))
    db = db.relationship('Database', backref='survey1', lazy='dynamic')

    def __init__(self, gender=None, age=None, education=None, language=None):
        self.gender=gender
        self.age=age
        self.education=education
        self.language=language

    def get_id(self):
        return unicode(self.id)

Forms.py

​​>

class Survey1(Form):
    gender=fields.RadioField('X', choices=[('Y','Y'),('Z','Z')],validators = [Required()])
    age=fields.RadioField('X', choices=[('Y','Y'),('Z','Z')], validators=[Required()])
    education = fields.RadioField('X',choices=[('Y','Y'),('Z','Z')],validators=[Required()])
    language = fields.TextField('Native Language', validators=[Required()])

如何存储此表单？

Answer 1

SQLAlchemy 的方法仅适用于 SQLAlchemy 对象 - 您的问题是您正在传递 WTForms Form 类的实例（SQLAlchemy 不知道如何持久保存到您的数据库）。一旦您更改 Form 声明以匹配 Model 类中的类型（gender、age、和education 在Model 类中都标记为Integer，但在Form 类中是String 字段）。

if form.validate_on_submit():
    model = models.Survey1()

    form.populate_obj(model)

    db.session.add(model)
    db.session.commit()
    return redirect(url_for('index'))