class Database:
    def __init__(self):
        self.save_schema = 'dwd'
        self.save_table = 'dwd_xxx'
        self.mysql_dwd_config = {
            'drivername': 'mysql+pymysql',
            'username': 'user_a',
            'password': 'xxx@#$xxx',
            'host': 'am-xxxxx.ads.aliyuncs.com',
            'port': 3306,
        }

        if sqlalchemy.__version__ > '1.4': #其实大于1.4.15之后，密码里面含有@，就必须以这种方式创建正确正则识别密码的引擎了。
            self.mysql_engine_url = sqlalchemy.engine.URL.create(**self.mysql_dwd_config)
        else:
            # password 含有@
            self.mysql_engine_url = '{drivername}://{username}:{password}@{host}:{port}'.format(**self.mysql_dwd_config)
        self.mysql_dwd_engine = sqlalchemy.create_engine(self.mysql_engine_url)

    @Usual.time_stat
    def drop_mysql(self):
        sql = f"DROP TABLE IF EXISTS {self.save_schema}.{self.save_table};"
        with self.mysql_dwd_engine.connect() as conn:
            conn.execute(sqlalchemy.text(sql))
        print('drop_table_done.')
        return

    @Usual.time_stat
    def get_mysql_data(self, sql, chunksize=None):
        if not chunksize:
            new_df = pd.read_sql(sql=sql, con=db.mysql_dwd_engine, chunksize=None)
        else:
            df_iter = pd.read_sql(sql=sql, con=db.mysql_dwd_engine, chunksize=chunksize)
            new_df = pd.DataFrame()
            for temp_df in df_iter:
                new_df = new_df.append(temp_df, ignore_index=True)
        print(f'get_df shape: {new_df.shape}')
        return new_df

    @Usual.time_stat
    def write_mysql_data(self, df, if_exists='replace'):
        df.to_sql(
            con=self.mysql_dwd_engine,
            schema=self.save_schema,
            name=self.save_table,
            if_exists=if_exists,
            index=False,
            index_label='id',
            chunksize=10000,
        )

-- 插入中文不仅是读写引擎的encoding=utf8mb4问题，一般现在都是默认的
-- 所以是创建schema的原始问题
create schema your_schema collate utf8mb4_unicode_ci;