AWS Lambda DynamoDB查询错误

Question

我正在使用python编写AWS Lambda函数。我正在使用boto3连接到DynamoDB数据库，并试图检索最后一个位置条目。

DynamoDB表的主分区键是“Serial”，它是一个字符串，主分类键是“Time”，也是一个字符串。

当我运行这段代码，试图获得序列“0001”，我得到以下错误

def getPriorGeofence(device): 
client = boto3.client('dynamodb') 
response = client.query(
    TableName='Locations', 
    IndexName='Serial', 
    Select='ALL_ATTRIBUTES', 
    Limit=1, 
    ScanIndexForward=True, 
    KeyConditions={ 
     "Serial":{ 
      'ComparisonOperator': "EQ", 
      'AttributeValueList': [device] 
     } 
    } 
    ) 
return response 

错误

{ 
    "stackTrace": [ 
    [ 
     "/var/task/lambda_function.py", 
     154, 
     "lambda_handler", 
     "priorGeofence = getPriorGeofence(serial)" 
    ], 
    [ 
     "/var/task/lambda_function.py", 
     110, 
     "getPriorGeofence", 
     "'AttributeValueList': [device]" 
    ], 
    [ 
     "/var/runtime/botocore/client.py", 
     253, 
     "_api_call", 
     "return self._make_api_call(operation_name, kwargs)" 
    ], 
    [ 
     "/var/runtime/botocore/client.py", 
     517, 
     "_make_api_call", 
     "api_params, operation_model, context=request_context)" 
    ], 
    [ 
     "/var/runtime/botocore/client.py", 
     572, 
     "_convert_to_request_dict", 
     "api_params, operation_model)" 
    ], 
    [ 
     "/var/runtime/botocore/validate.py", 
     270, 
     "serialize_to_request", 
     "raise ParamValidationError(report=report.generate_report())" 
    ] 
    ], 
    "errorType": "ParamValidationError", 
    "errorMessage": "Parameter validation failed:\nInvalid type for parameter KeyConditions.Serial.AttributeValueList[0], value: 0001, type: <type 'unicode'>, valid types: <type 'dict'>" 
} 

Answer 1

更改AttributeValueList下面所提到的值中的最后一项（即将数据类型明确提及为字符串'S'）： -

KeyConditions={ 
     "Serial":{ 
      'ComparisonOperator': "EQ", 
      'AttributeValueList': [{'S' : device}] 
     } 
    }