在BigQuery数据传输中，数据回填和刷新是两种常用的数据迁移方式。数据回填用于将历史数据导入到BigQuery中，而数据刷新则用于将现有数据更新到BigQuery中。以下是实现这两种方法的代码示例：

1. 数据回填示例：

使用BigQuery数据传输API在Python中实现数据回填:

from google.cloud import bigquery_datatransfer_v1
from google.protobuf.json_format import MessageToDict
client = bigquery_datatransfer_v1.DataTransferServiceClient()
PROJECT_ID = ''
DESTINATION_DATASET_ID = ''
TRANSFER_CONFIG_ID = ''
SOURCE_PROJECT_ID = ''
SOURCE_DATASET_ID = ''
TABLE_NAME = ''
RUN_TIME = ''
TRANSFER_CONFIG_NAME = client.transfer_config_path(PROJECT_ID, TRANSFER_CONFIG_ID)
request = {
    "parent": client.project_path(PROJECT_ID),
    "source_database": {
        "project_id": SOURCE_PROJECT_ID,
        "database_id": SOURCE_DATASET_ID
    },
    "destination_dataset_id": DESTINATION_DATASET_ID,
    "display_name": TRANSFER_CONFIG_NAME,
    "params": {
        "table_name_template": TABLE_NAME,
        "query": "",
        "destination_table_suffix": "",
        "data_path_template": "",
        "file_format": "",
        "field_delimiter": "",
        "skip_leading_rows": "",
        "destination_table_name_template": "",
        "overwrite_destination_table": False,
        "write_disposition": "",
        "partitioning_field": "",
        "partitioning_type": "",
        "start_time": RUN_TIME,
        "end_time": RUN_TIME,
        "schedule_options": {
            "disable_auto_scheduling": True,
            "start_time": None,
            "end_time": None,
            "schedule_end_time": None,
            "schedule_start_time": None,
            "schedule_duration": None,
            "disable_manual_runs": False,
            "schedule_display_timezone": "",
            "schedule_custom_timezone": None
        },
        "notification_pubsub_topic": "",
        "email_preferences": [],