问题描述
我有一个包含列Id和JSON列的表。
I have a table with column Id and JSON column.
Id | JSON
----------------------------------------------------------------
101 | {"person_id":456,"f_name":"t", "l_name":"Jack"}
|
102 | {"person_id":123,"f_name":"M", "l_name":"Ron"}
|
103 | {"person_id":789,"f_name":"A", "l_name":"Tom"}
我能够在列Id上创建GSI（全局二级索引），但我想知道如何在 person_id 和 f_name上创建GSI 。是否可以为json属性创建GSI？在观察时，我能够在Dynamo DB表中的列上创建GSI。请提供C＃.Net示例 ..
I am able to create GSI(Global Secondary Index) on column Id , but I would like to know how to create GSI on person_id and f_name. Is it possible to create GSI for json attributes? As upon observation, I was able to create GSI on columns in tables of Dynamo DB..Please provide a C#.Net example..
推荐答案
取自
否。您可以在任何顶级JSON元素上创建全局二级索引或本地二级索引
。例如，假设您存储了一个JSON
文档，其中包含有关某人的以下信息：
名字，姓氏，邮政编码以及所有朋友的列表。
名字，姓氏和邮政编码将是顶级JSON元素。
您可以创建一个索引，让您根据名字，最后
名称或邮政编码进行查询。朋友列表不是顶级元素，
因此您无法索引朋友列表。有关全局二级索引及其查询功能的
的更多信息，请参阅此常见问题解答中的
二级索引部分。
No. You can create a Global Secondary Index or Local Secondary Index on any top-level JSON element. For example, suppose you stored a JSON document that contained the following information about a person: First Name, Last Name, Zip Code, and a list of all of their friends. First Name, Last Name and Zip code would be top-level JSON elements. You could create an index to let you query based on First Name, Last Name, or Zip Code. The list of friends is not a top-level element, therefore you cannot index the list of friends. For more information on Global Secondary Indexing and its query capabilities, see the Secondary Indexes section in this FAQ.
问：如果我已嵌套DynamoDB中的JSON数据，我只能检索该数据的
特定元素吗？
Q: If I have nested JSON data in DynamoDB, can I retrieve only a specific element of that data?
是。使用GetItem，BatchGetItem，Query或Scan API时，
可以定义ProjectionExpression以确定应从表中检索哪些属性
。这些属性可以包括标量，
集或JSON文档的元素。
Yes. When using the GetItem, BatchGetItem, Query, or Scan APIs, you can define a ProjectionExpression to determine which attributes should be retrieved from the table. Those attributes can include scalars, sets, or elements of a JSON document.
虽然我没有设法做它，或看到任何云形成的例子。
Although I haven't managed to do it, or seen any examples of it being done with cloud formation.
这篇关于如何在C＃中的Amazon Dynamo DB中为Json属性（列值）创建全局二级索引？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！