我正在使用sqlalchemy管理2个数据库。一个是本地sqlite数据库，另一个是google云平台上的远程mysql数据库，它们共享相同的模式。我试图使用append将sqlite数据库中包含的行添加到mysql数据库中。我目前有一个文件定义了我的类，如下所示：
传感器采集.py

class Readings(Base):
    __tablename__ = 'readings'

    time = Column(String(250), primary_key=True)
    box_name = Column(String(250))
    FS = Column(Numeric)
    IS = Column(Numeric)
    VS = Column(Numeric)
    CO = Column(Numeric)
    TVOC = Column(Numeric)
    cTemp = Column(Numeric)
    fTemp = Column(Numeric)
    humidity = Column(Numeric)
    pressure = Column(Numeric)

然后我有另一个文件声明我的基、会话和引擎：
基本.py

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

engine = create_engine('sqlite:///%s' % 'db/db.db')
Session = sessionmaker(bind=engine)
Base = declarative_base()

最后是我的实际代码：

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.schema import Table
from SensorCollection import Readings
from sqlalchemy.sql.expression import insert

# uploads MySQL database to Google cloud server

# uses ORM to ensure the databases can communicate with each other

user =***
password =***
host =***
port =***
dbName =***
instanceConnectionName =***

# create the engine for the local db

engineLocal = create_engine('sqlite:///%s' % 'db/db.db')
BaseLocal = Readings(None, None, None, None, None, None, None, None, None, None, None)

# create the engine for the Google db

engineGoogle = create_engine('mysql+mysqldb://%s@%s:%s/%s?unix_socket=/cloudsql/%s' % (user, host, port, dbName, instanceConnectionName))
SessionGoogle = sessionmaker(bind=engineGoogle)
BaseGoogle = Readings(None, None, None, None, None, None, None, None, None, None, None)

# create the local db

BaseLocal.metadata.create_all(engineLocal)

# create the Google db and start the session

BaseGoogle.metadata.create_all(engineGoogle)
sessionGoogle = SessionGoogle()

# create table objects for each db

t1 = Table('readings', BaseLocal.metadata, autoload=True, autoload_with=engineLocal)
t2 = Table('readings', BaseGoogle.metadata, autoload=True, autoload_with=engineGoogle)

# the first subquery, select all ids from SOME_TABLE where some_field is not NULL

s1 = t1.select()

# the second subquery, select all ids from SOME_TABLE where some_field is NULL

s2 = t2.select()

# union s1 and s2 subqueries together and alias the result as "alias_name"

q = s1.union(s2)

insert(t2, s1)
sessionGoogle.query(q)

# sessionGoogle.add_all(s1)

# commit changes and close the session

sessionGoogle.commit()
sessionGoogle.close()

目前，sqlite数据库已经存在，远程服务器已经设置好，但是当它连接到google时，代码甚至没有创建表。它似乎连接正确，因为如果我改变任何服务器的细节，我会得到一个mysql错误。它也不会给我任何错误。它编译并运行，但不附加数据，甚至不创建表。这是我第一次尝试任何类型的数据库，所以我敢肯定它充满了错误，一点也不优雅。任何帮助都将不胜感激。
edit djkern帮助我创建了表，并更新了代码。不过，我还没有得到要追加的数据。