文章目录
尽管MySQL默认约束类型为RESTRIC,但若不设置从表中关联列的nullable=False,那么通过sqlalchemy的ORM删除数据不会报错!!
class User(Base):
__tablename__ = 'user'
id = Column(Integer,primary_key=True,autoincrement=True)
username= Column(String(50),nullable=False)
articles = relationship("Article",backref="tags")
def __repr__(self