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

问题描述

你好，我有一个动态表。我想让服务返回此表中的所有项目，并且顺序是通过对一个属性进行排序。

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.

是否需要为此创建全局二级索引？如果是这样，那么哈希键应该是什么，范围键是什么？
（请注意，对gsi的查询必须在GSI的哈希键上指定一个 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！

Erben

推荐答案

如果您知道HashKey，则任何查询都将返回排序方式为范围键。从文档：

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

查询结果始终按范围键排序。如果范围键的数据类型为 Number ，则结果以数字顺序返回。否则，将按UTF-8字节的顺序返回结果。默认情况下，排序顺序为升序。要颠倒顺序，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，如果您需要退回 all 个项目，则应使用扫描程序。您无法订购扫描结果。

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，您看到GSI仅包含HashKey。我猜结果将按此键排序（我尚未在程序中检查此部分！）。

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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