在使用SQLAlchemy创建表后,如何向其中添加其他列？

Question

到目前为止这是我的文件:

from sqlalchemy import create_engine, ForeignKey
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship, backref
from sqlalchemy import Column, Integer, String
from sqlalchemy import Table, Text

engine = create_engine('mysql://root:ababab@localhost/alctest',
            echo=False)

Base = declarative_base()

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key = True)
    name = Column(String(100))
    fullname = Column(String(100))
    password = Column(String(100))
    addresses = relationship("Address", order_by="Address.id", backref="user")

    def __init__(self, name, fullname, password):
        self.name = name
        self.fullname = fullname
        self.password = password

    def __repr__(self):
        return "<User('%s','%s', '%s')>" % (self.name, self.fullname, self.password)


class Address(Base):
    __tablename__ = 'addresses'
    id = Column(Integer, primary_key = True)
    email_address = Column(String(100), nullable=False)

    #foreign key, must define relationship
    user_id = Column(Integer, ForeignKey('users.id'))
    user = relationship("User", backref = backref('addresses',order_by=id))

Base.metadata.create_all(engine)

这个文件很简单.它创建一个用户和地址表.运行此文件后,将创建表.

但现在我想在"用户"中添加一列.我怎样才能做到这一点？我需要做什么？

Answer 1

您可以使用Table.append_column方法添加列。

test = Column('test', Integer)
User.__table__.append_column(test)

但这不会触发ALTER TABLE在数据库中添加该列的命令。根据append_column为该命令提供的文档，您必须在模型中添加该列后手动运行。