SqlAlchemy 公用连接类

from sqlalchemy import create_engine, MetaData
from sqlalchemy.ext.automap import automap_base
from sqlalchemy.orm import Session


class SqlAlchemyDB(object):
    def __init__(self, _dbname, _tables):
        self.dbName = _dbname
        print('connection..  ', self.dbName)
        connect_string = "mssql+pymssql://user:password@db_url:3433/" + _dbname + "?charset=utf8"
        self.engine = create_engine(connect_string)
        self.meatdata = MetaData()
        self.meatdata.reflect(bind=self.engine, only=_tables)
        self.base = automap_base(metadata=self.meatdata)
        self.base.prepare()
        self.session = Session(self.engine)