DynamoDB:如何创建具有嵌套 JSON 结构的表? [英] DynamoDB: How can I create a table with nested JSON structure?

问题描述

我想在 dynamoDB 中创建一个具有以下结构的表.

I want to create a table in dynamoDB with below structure.

{
  "CartId": 123,
  "UserId": 356,
  "CartItems": [
    {
      "ProductId": 100,
      "Quantity": 50
    },
    {
      "ProductId": 121,
      "Quantity": 51
    }
  ]
}

在教程和文档中到处都说我们只能在表中具有以下类型的属性:

Everywhere in tutorials and documents it says that we can only have below type of attributes in the table:

1. 字符串集

1. Set of Strings

一组数字

二进制集

我想不出在 DynamoDB 中存储上述结构的方法.你能帮忙吗?

I can't think of a way to store above structure in DynamoDB. Could you please help out?

我正在使用 java 的对象映射器 Api.如果您还可以告诉我如何创建一个可以映射到这个特定表结构的类，那就太好了.

I am using object mapper Api of java. It would be great if you can also tell me how can I create a class which can be mapped to this particular table structure.

推荐答案

最简单的方法是使用 @DynamoDBDocument

1. 添加 Maven 依赖项

<dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk-dynamodb</artifactId>
        <version>1.11.186</version>
</dependency>

1. 创建 POJO

@DynamoDBTable(tableName = "Customer")
public class Customer
{ 
    @DynamoDBHashKey
    @DynamoDBAutoGeneratedKey
    private String id;

    private String firstName;

    private List<Foo> fooList;
}

@DynamoDBDocument
public static class Foo {
    private String name;
}

1. 创建存储库

@EnableScan
public interface CustomerRepository extends CrudRepository<Customer,String>

然后调用customerRepository.save(customer).结果会是这样的:

Then call customerRepository.save(customer). The result will be like this:

{
  "firstName": "Test",
  "fooList": [
    {
      "name": "foo"
    },
    {
      "name": "foo2"
    }
  ],
  "id": "e57dd681-8608-4712-a39a-f3e0f31a5e27"
}

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