无法使用 python 从 AWS dynamodb 获取 get_item？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/37589254/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Not able to get_item from AWS dynamodb using python?
提问by Narendra M
I am new to dynamodb trying to get data from dynamodb.
我是 dynamodb 的新手，试图从 dynamodb 获取数据。
This is my table with "topic" as a primary hash key
my python code
我的蟒蛇代码
import boto3
from boto3 import dynamodb
from boto3.session import Session
from boto3.dynamodb.conditions import Key, Attr
dynamodb_session = Session(aws_access_key_id='XXXXXXXXXXXXXXX',
aws_secret_access_key='XXXXXXXXXXXXXXXXXXXXXXXXXXXX',
region_name='us-east-1')
dynamodb = dynamodb_session.resource('dynamodb')
table=dynamodb.Table('Garbage_collector_table')
my_topic = "$aws/things/garbage_collector_thing/shadow/update/accepted"
response = table.get_item(TableName='Garbage_collector_table', Key={'topic':my_topic})
for res in response:
print "result ",res
I am getting the following error
我收到以下错误
Traceback (most recent call last):
File "get-data-dynamodb-boto3.py", line 19, in <module>
response = table.get_item(TableName='Garbage_collector_table', Key={'topic': my_topic}) File
"/usr/local/lib/python2.7/dist-packages/boto3/resources/factory.py",
line 518, in do_action
response = action(self, *args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/boto3/resources/action.py",
line 83, in __call__
response = getattr(parent.meta.client, operation_name)(**params) File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line
258, in _api_call
return self._make_api_call(operation_name, kwargs) File /usr/local/lib/python2.7/dist-packages/botocore/client.py", line 548,
in _make_api_call
raise ClientError(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (ValidationException) when calling the GetItem operation: The provided key element does not match the schema
botocore.exceptions.ClientError: 调用 GetItem 操作时发生错误 (ValidationException)：提供的关键元素与架构不匹配
am I missing anything in my code?
我的代码中是否缺少任何内容？
回答by Eyal Ch
You are mixing resource and client objects which have different methods. More info here.
您正在混合具有不同方法的资源和客户端对象。更多信息在这里。
The correct syntax for a resource is:
资源的正确语法是：
response = table.get_item(Key={'topic': my_topic})
but personally I recommend to use boto client:
但我个人建议使用 boto 客户端：
client = boto3.client('dynamodb')
response = client.get_item(TableName='Garbage_collector_table', Key={'topic':{'S':str(my_topic)}})
http://boto3.readthedocs.io/en/latest/reference/services/dynamodb.html
http://boto3.readthedocs.io/en/latest/reference/services/dynamodb.html
回答by Tomiwa
You can also query the database:
您还可以查询数据库：
from boto3.dynamodb.conditions import Key
table = dynamodb.Table(table_name)
response = table.query(
KeyConditionExpression=Key('topic').eq(my_topic)
)
items = response['Items']
if items:
return items[0]
else:
return []
Source: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStarted.Python.04.html
来源：https: //docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStarted.Python.04.html
回答by kartik
Assuming you only have partition key (aka hash key) in the table.
假设您在表中只有分区键（又名散列键）。
import boto3
dynamodb = boto3.resource('dynamodb',region_name='ap-southeast-2')
table = dynamodb.Table('my-table')
key = {}
key['key'] = 'my-key'
print(key)
response = table.get_item(Key=key)
print(response['Item'])
回答by mprivat
There are actual examples here: https://boto3.amazonaws.com/v1/documentation/api/latest/guide/dynamodb.html
这里有实际例子：https: //boto3.amazonaws.com/v1/documentation/api/latest/guide/dynamodb.html
In your case, you need to do this:
在你的情况下，你需要这样做：
response = table.get_item(TableName='Garbage_collector_table', Key={'topic': my_topic})
