谢谢大家。
代码如下，总是会提示这个错误：
sqlalchemy.exc.NoForeignKeysError: Could not determine join condition between parent/child tables on relationship Problem.tags - there are no foreign keys linking these tables via secondary table 'problem_tags'. Ensure that referencing columns are associated with a ForeignKey or ForeignKeyConstraint, or specify 'primaryjoin' and 'secondaryjoin' expressions.
tags_table = db.Table('problem_tags',
db.Column('problem_id', db.Integer, db.ForeignKey('problem.id')),
db.Column('tag_id', db.Integer, db.ForeignKey('problemtag.id'))
)
class ProblemTag(db.Model):
id=db.Column(db.Integer, primary_key=True)
name=db.Column(db.String(80))
problems = db.relationship('Problem',secondary=tags_table,
backref=db.backref('tags', lazy='dynamic'))
def __init__(self,name):
self.name=name
def __repr__(self):
return "<Tag %r>" % self.name
class Problem(db.Model):
id=db.Column(db.Integer, primary_key=True)
title=db.Column(db.String(80))
tags = db.relationship('ProblemTag',secondary=tags_table,
backref=db.backref('problems', lazy='dynamic'))
def __init__(self,title,tags):
self.title=title
self.tags=tags
def __repr__(self):
return "<Problem %r>" % self.title
添加回答
举报
0/150
提交
取消