Dynamodb 按排序顺序扫描 [英] Dynamodb scan in sorted order

问题描述

我有一个 dynamodb 表.我希望该服务返回此表中的所有项目，并且顺序是按一个属性排序.

Hi I have a dynamodb table. I want the service to return me all the items in this table and the order is by sorting on one attribute.

我需要为此创建全局二级索引吗?如果是这样，散列键应该是什么，范围键是什么?(注意gsi查询必须在GSI的hash key上指定一个EQ"比较器.)

Do I need to create a global secondary index for this? If that is the case, what should be the hash key, what is the range key? (Note that query on gsi must specify a "EQ" comparator on the hash key of GSI.)

非常感谢！

二本

推荐答案

如果您知道 HashKey，那么任何查询都将返回按 Range 键排序的项目.来自文档:

If you know the HashKey, then any query will return the items sorted by Range key. From the documentation:

查询结果总是按范围键排序.如果范围键的数据类型为Number，则按数字顺序返回结果.否则，按 UTF-8 字节顺序返回结果.默认情况下，排序顺序是升序.要反转顺序，请将 ScanIndexForward 参数设置为 false.

Query results are always sorted by the range key. If the data type of the range key is Number, the results are returned in numeric order. Otherwise, the results are returned in order of UTF-8 bytes. By default, the sort order is ascending. To reverse the order, set the ScanIndexForward parameter set to false.

现在，如果您需要返回所有项目，您应该使用扫描.您无法对扫描结果进行排序.

Now, if you need to return all the items, you should use a scan. You cannot order the results of a scan.

另一种选择是使用 GSI(示例).在这里，您会看到 GSI 仅包含 HashKey.结果我猜会按照这个key的顺序排列(我还没有在程序中检查过这部分！).

Another option is to use a GSI (example). Here, you see that the GSI contains only HashKey. The results I guess will be in sorted order of this key (I didn't check this part in a program yet!).

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