sqlalchemy orm 异常 非映射实例错误 Flask WTForm

Question

我在显示相关表格以供输入时出现以下错误。在

sqlalchemy.orm.exc.UnmappedInstanceError UnmappedInstanceError: Class 'sqlalchemy.util._collections.result' is not mapped

这是models.py

class Project(db.Model):
__tablename__ = 'projects'
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(175), unique=True, nullable=False)
description = db.Column(db.Text)
#---------------------------
region = db.Column(db.Integer, db.ForeignKey('regions.id'))
district  = db.Column(db.Integer, db.ForeignKey('districts.id'))
subdistrict  = db.Column(db.Integer, db.ForeignKey('subdistricts.id'))
village = db.Column(db.Integer, db.ForeignKey('villages.id'))
#------------------------------------
baseline = db.Column(db.Text())
performance_indicator = db.Column(db.Text)
budget = db.Column(db.Float())
author = db.Column(db.Integer, db.ForeignKey('users.id'))
posted_date = db.Column(db.DateTime)
start_date = db.Column(db.DateTime)
est_completion = db.Column(db.DateTime)
mark_complete = db.Column(db.Boolean, default=False)
activities = db.relationship('Activity', backref='projects', cascade='all, delete-orphan', lazy='dynamic')
remarks = db.relationship('Remark', backref='projects', cascade='all, delete-orphan', lazy='dynamic')
beneficiary = db.Column(db.Integer, db.ForeignKey('beneficiaries.id'))
sector =  db.Column(db.Integer, db.ForeignKey('sectors.id'))
media = db.relationship('Media', secondary=projects_media, backref='projects')

def __init__(self, id, title, description, baseline, performance_indicator, budget, remark, remark_author, author, posted_date, start_date, est_completion, mark_complete):
    self.id = id
    self.title = title
    self.description = description
    self.baseline = baseline
    self.performance_indicator = performance_indicator
    self.budget = budget
    self.author = author
    self.posted_date = posted_date
    self.start_date = start_date
    self.est_completion = est_completion
    self.mark_complete = mark_complete

forms.py

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最后我的views.py

@app.route('/add', methods=['GET', 'POST'])
def deliverables():
    forms = ProjectForm()
    if request.method == 'POST' and forms.validate_on_submit():
        pmodel = Project(title=forms.title.data,description=forms.description.data, baseline=forms.baseline.data, performance_indicator=forms.performance_indicator.data, budget=forms.budget.data, author='mainuser', posted_date=datetime.datetime.utcnow(), start_date=forms.started.data, est_completion=forms.estimated_completion.data, mark_complete=forms.completed.data)
    db.session.add(pmodel)
    db.session.commit()
return render_template('front/deliverables_edit.html', forms=forms)

Answer 1

query_factory回调应该返回完整的实体，而不是列

def sector_lists():
    return db.session.query(Sector)

def region_lists():
    return db.session.query(Region)

def district_lists():
     return db.session.query(District)

Answer 2

作为您的代码：

def sector_lists():
    return db.session.query(Sector.name)

无法将列返回到QuerySelectField的查询工厂（必须返回查询），您已在QuerySelectField的get_标签处指定：

sector = QuerySelectField(get_label='Service Sector',query_factory=sector_lists)

够了。必须更改函数sector_lists：

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