关于flask-admin的一个疑问

[jiamengwei]

https://www.cnblogs.com/magicroc/p/6103773.html?utm_source=itdadao&utm_medium=referral 我是在上面这个链接看到的你，我有一个小小的疑问想向你请教， 我在使用flask-admin生成的后台的时候遇到了一个问题，我有一个文章分类表Category和一个文章表Article，在我添加一个文章后，再去添加分类会出现错误：ValueError: too many values to unpack (expected 2) 而且删除一个文章分类的时候（这个分类下有文章），可以直接删除。。。这样的话外键不是没意义了么

class Article(db.Model):
    __tablename__ = 'article'
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(20), nullable=False)
    writer = db.Column(db.String(10), nullable=False)
    content = db.Column(db.Text, nullable=False)
    add_time = db.Column(db.DateTime,  default=datetime.now)
    category_id = db.Column(db.Integer, db.ForeignKey('category.id'))
    comment = db.relationship('Comment', backref='article', lazy='dynamic')

    def __repr__(self):
        return '<title %r>' % self.title

class Category(db.Model):

    __tablename__ = 'category'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(10), nullable=False,unique=True)
    description = db.Column(db.String(120), nullable=False)
    add_time = db.Column(db.DateTime, default=datetime.now)
    articel = db.relationship('Article', backref='category', lazy='dynamic')

    def __repr__(self):
        return '<name %r>' % self.name

[huang-zp]

当你添加分类的时候是去Category表中新建一个实例再去文章中选择这个实例吗？ ValueError: too many values to unpack (expected 2)这种错误一般是把一个列表、元组这样的数据结构的值拿出来赋值给接收方，接收方变量个数不够造成到错误 例如：

Python 3.6.4 (default, Feb 5 2018, 14:21:54) [GCC 5.4.0 20160609] on linux Type "help", "copyright", "credits" or "license" for more information. >>> a, b = [1, 2, 3] Traceback (most recent call last): File "", line 1, in ValueError: too many values to unpack (expected 2) >>> a, b = (1, 2, 3) Traceback (most recent call last): File "", line 1, in ValueError: too many values to unpack (expected 2) >>> a, b, c = (1, 2, 3) >>> a 1 >>> b 2 >>> c 3