Python - 使用 Boto3 从 DynamoDB 检索最大主键值 [英] Python - Retrieving max primary key value from DynamoDB using Boto3

问题描述

我只是想通过使用 Boto3 的查询/扫描来检索我的主键的最大值.我正在尝试完成此操作，因此我的程序可以简单地将我设置为等于最大ID"值的变量增加 1 以用于下一个表条目.

I'm simply trying to retrieve the max value of my primary keys with a query/scan using Boto3. I'm trying to accomplish this so my program can simply increment a variable I'll set equal to the max "ID" value by 1 for the next table entry.

DynamoDB 表的屏幕截图

response = table.scan(
    FilterExpression=Attr('ID'). #Here is where I'd assume a condition
)                                #is placed to find the highest value but
                                 #the Boto3 doc doesn't seem to have a 
                                 #method like 'max()' or something...

四处搜索我发现如何使用原始的boto"来做到这一点，所以我确信有一种方法可以使用它的新版本boto3"，但我还没有找到任何东西.

Searching around I found how to do this using the original 'boto' so I'm sure there is a way using its newer version 'boto3' but I haven't found anything yet.

任何帮助/指导将不胜感激！谢谢！

Any help/guidance would be greatly appreciated! Thanks!

Boto3 文档:http://boto3.阅读thedocs.io/en/latest/guide/dynamodb.html#querying-and-scanning

推荐答案

我遇到了同样的问题，找不到优雅的解决方案.但是，如果您的主键只是整数，您可以执行以下操作来查找最大键:

I am suffering from the same issue and can't find an elegant solution. However if your primary keys are just integers you can do something like this to find the max key:

import boto3

dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table(table_name)
max_key = table.item_count

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