是否可以在DynamoDB中附加到多值属性？ [英] Is it possible to append to multi-valued attributes in DynamoDB?

问题描述

是否可以在Amazon DynamoDB表的多值属性中附加值列表？我不太能够使用put请求弄清楚。我想尽可能避免读取，更新，写入逻辑。

Is it possible to append to the list of values in a multi-valued attribute in an Amazon DynamoDB table? I am not quite able to figure it out using the put request. I would like to avoid the read, update, write logic if possible.

推荐答案

假设您是指 String和亚马逊中概述的数字集 DynamoDB数据类型，这可以在 Amazon DynamoDB 中通过 UpdateItem 操作确实是：

Assuming you are referring to String and Number Sets as outlined in Amazon DynamoDB Data Types, this is possible in Amazon DynamoDB by means of the UpdateItem operation indeed:

ADD — 仅对数字或目标属性为集合（包括字符串集合）的情况下使用添加操作。如果
目标属性是单个字符串值，则ADD不起作用。指定的值是
添加到一个数值（递增或递减现有的
数值）或作为附加值添加到字符串集中。如果指定了
值集，则将值添加到现有的值集中。
例如，如果原始值是[1,2]，并且提供的值是 3 ，
，然后在添加操作之后，集合为[1,2， 3]，而不是[4,5]。 [...]
[强调我]

ADD— Only use the add action for numbers or if the target attribute is a set (including string sets). ADD does not work if the target attribute is a single string value. The specified value is added to a numeric value (incrementing or decrementing the existing numeric value) or added as an additional value in a string set. If a set of values is specified, the values are added to the existing set. For example if the original set is [1,2] and supplied value is 3, then after the add operation the set is [1,2,3], not [4,5]. [...] [emphasis mine]

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