如何重命名DynamoDB列/键 [英] How to rename DynamoDB column/key

问题描述

在我的DynamoDb表之一中，我有一个名为状态的列/键，事实证明这是一个保留关键字。不幸的是，不能删除整个表并重新启动它。如何重命名密钥？

In one of my DynamoDb tables I have a column/key named "status", which turned out to be a reserved keyword. Unfortunately it isn't an option to delete the whole table and reinitiate it. How can I rename the key?

以下是导致异常的Lambda代码：

Here is the Lambda Code that causes the Exception:

try :
            response = table.query(
                IndexName='myId-index',
                KeyConditionExpression=Key('myId').eq(someId)
            )
            for item in response['Items']:
                print('Updating Item: ' + item['id'])
                table.update_item(
                    Key={
                        'id': item['id']
                    },
                    UpdateExpression='SET myFirstKey = :val1, mySecondKey = :val2, myThirdKey = :val3, myFourthKey = :val4, myFifthKey = :val5, status = :val6',
                    ExpressionAttributeValues={
                        ':val1': someValue1,
                        ':val2': someValue2,
                        ':val3': someValue3,
                        ':val4': someValue4,
                        ':val5': someValue5,
                        ':val6': someValue6
                    }
                )
except Exception, e:
            print ('ok error: %s' % e)

这是例外：

2016-06-14 18:47:24 UTC + 2
ok错误：调用UpdateItem操作时发生错误（ValidationException）：无效的UpdateExpression：属性名称是保留关键字;保留关键字：status

2016-06-14 18:47:24 UTC+2 ok error: An error occurred (ValidationException) when calling the UpdateItem operation: Invalid UpdateExpression: Attribute name is a reserved keyword; reserved keyword: status

推荐答案

没有真正简单的方法来重命名列。您将必须为每个条目创建一个新属性，然后删除现有属性的所有值。

There is no real easy way to rename a column. You will have to create a new attribute for each of the entries and then delete all the values for the existing attribute.

没有理由删除您的属性/列，如果查询表时遇到问题，请使用表达式属性名称。

There is no reason to drop your attribute/column, if you are having trouble querying the table use Expression Attribute Names.

来自表达式属性名称文档：

在某些情况下，可能需要编写包含与DynamoDB保留字冲突的属性名称的表达式。要解决此问题，您可以定义一个表达式属性名称。 表达式属性名称是您在表达式中使用的占位符，代替了实际的属性名称。

On some occasions, you might need to write an expression containing an attribute name that conflicts with a DynamoDB reserved word... To work around this, you can define an expression attribute name. An expression attribute name is a placeholder that you use in the expression, as an alternative to the actual attribute name.

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