我正在尝试在其他表中将自动递增的唯一ID字段用作外键。我的模型如下:
class User(Base):
__tablename__ = 'Users'
uid = Column(INT, primary_key=True, autoincrement=True)
name = Column(TEXT)
email = Column(TEXT)
dateRegistered = Column(TIMESTAMP)
phone = Column(TEXT)
class AddressMap(Base):
__tablename__ = 'AddressMaps'
uid = Column(INT, primary_key=True, autoincrement=True)
userId = Column(INT, ForeignKey('Users.uid'))
addressId = Column(INT, ForeignKey('Addresses.uid'))
dateCreated = Column(TIMESTAMP)
user = relationship("User", backref=backref('AddressMaps'))
address = relationship("Address", backref=backref('AddressMaps'))
class Address(Base):
__tablename__ = 'Addresses'
uid = Column(INT, primary_key=True, autoincrement=True)
street = Column(TEXT)
city = Column(TEXT)
state = Column(TEXT)
postal = Column(TEXT)
dateRegistered = Column(TIMESTAMP)
我的问题是,当我创建一个用户对象时,它不是用uid值创建的。我理解这是因为对象尚未提交到数据库。问题是,由于用户对象没有uid值,所以我无法将AddressMap对象与其链接。
在SQLAlchemy中,处理这个问题的惯用方法是什么?
最佳答案
你不应该需要uid。由于在表之间创建了一个关系,因此可以向用户添加一个AddressMap
对象:
samantha = User(name='Sam', email='[email protected]', phone='555-555-5555')
现在您可以访问
samantha.AddressMaps
集合(请参见backref
表中user
关系下的AddressMap
)。您可以将AddressMap
对象添加到此集合:samantha.AddressMaps = [AddressMap(dateCreated=datetime.now()),
AddressMap(dateCreated=datetime.min)]
现在您可以将这些对象添加到
session
和commit
中。有关更多信息,请参见the docs。顺便说一下,作为FYI,you don't need to include
autoincrement=True
在表的第一个整数列上。关于python - sqlalchemy自动增量值作为外键mysql,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/27497666/