Python脚本将SAP数据提取至AWS Glue时遇'unhashable type: dict'错误

错误根源 #

错误"unhashable type: 'dict'"出现在创建Pandas DataFrame的环节。pyrfc调用RFC_READ_TABLE后返回的FIELDS是字典数组（每个字典包含FIELDNAME等属性），而非直接的字符串列名，直接将其传给pd.DataFrame的columns参数会触发该错误——因为字典属于不可哈希类型，无法作为列名使用。

修复步骤 #

1. 提取纯字符串列名：从FIELDS字典数组中提取FIELDNAME字段值，生成字符串类型的列名列表
2. 拆分行数据：DATA返回的每行是包含WA键的字典，需将WA值按指定分隔符拆分，匹配对应列名
3. 修正RFC参数格式：pyrfc要求FIELDS参数为字典列表（每个字典含FIELDNAME键），原脚本的字符串列表不符合规范

修正后的完整脚本 #

from pyrfc import Connection
import pandas as pd

## Variables
sap_table = 'TABLENAME' # SAP Table Name
fields = ["FIELD1", "FIELD2"] # List of fields 
options = [""] 
max_rows = 10
from_row = 0 
delimiter = '|'

try:
    # Establish SAP RFC connection
    conn = Connection(ashost='mysapserver.com', sysnr='00', client='000', user='username', passwd='password') 
    print(f"SAP Connection successful – connection object: {conn}")
    
    if conn:
        # Read SAP Table information
        tables = conn.call(
            "RFC_READ_TABLE", 
            QUERY_TABLE=sap_table, 
            DELIMITER=delimiter, 
            FIELDS=[{"FIELDNAME": field} for field in fields],
            OPTIONS=options, 
            ROWCOUNT=max_rows, 
            ROWSKIPS=from_row
        ) 
        
        # 提取字段名列表
        columns = [field["FIELDNAME"] for field in tables["FIELDS"]]
        # 拆分每行的WA数据为列值
        data_rows = [row["WA"].split(delimiter) for row in tables["DATA"]]
        
        df = pd.DataFrame(data_rows, columns=columns)
        
        if not df.empty:
            print(f"Successfully extracted data from SAP using custom RFC - Printing the top 5 rows:\n{df.head(5)}") 
        else:
            print("No data returned from the request. Please check database/schema details")
    else:
        print("Unable to connect with SAP. Please check connection details")
except Exception as e:
    print(f"An exception occurred while connecting with SAP system: {e.args}")

额外注意事项 #

• 若字段值本身包含分隔符|，拆分时会出错，建议选用SAP数据中不存在的字符作为分隔符（如~）
• RFC_READ_TABLE返回的所有数据均为字符串类型，需根据业务需求自行转换字段类型（如数字、日期）

内容的提问来源于stack exchange，提问作者John