查询 DynamoDb 全局二级索引

Question

我正在本地试用 dynamodb 并得到以下结果 table:

"Table": {
    "AttributeDefinitions": [
        {
            "AttributeName": "hashKey",
            "AttributeType": "S"
        },
        {
            "AttributeName": "sortKey",
            "AttributeType": "S"
        },
        {
            "AttributeName": "full_json",
            "AttributeType": "S"
        }
    ],
    "TableName": "local",
    "KeySchema": [
        {
            "AttributeName": "hashKey",
            "KeyType": "HASH"
        },
        {
            "AttributeName": "sortKey",
            "KeyType": "RANGE"
        }
    ],
    "TableStatus": "ACTIVE",
    "CreationDateTime": "2021-10-01T15:18:04.413000+02:00",
    "ProvisionedThroughput": {
        "LastIncreaseDateTime": "1970-01-01T01:00:00+01:00",
        "LastDecreaseDateTime": "1970-01-01T01:00:00+01:00",
        "NumberOfDecreasesToday": 0,
        "ReadCapacityUnits": 5,
        "WriteCapacityUnits": 1
    },
    "TableSizeBytes": 1066813,
    "ItemCount": 23,
    "TableArn": "arn:aws:dynamodb:ddblocal:000000000000:table/local",
    "GlobalSecondaryIndexes": [
        {
            "IndexName": "sortKeyIndex",
            "KeySchema": [
                {
                    "AttributeName": "sortKey",
                    "KeyType": "HASH"
                }
            ],
            "Projection": {
                "ProjectionType": "ALL"
            },
            "IndexStatus": "ACTIVE",
            "ProvisionedThroughput": {
                "ReadCapacityUnits": 10,
                "WriteCapacityUnits": 1
            },
            "IndexSizeBytes": 1066813,
            "ItemCount": 23,
            "IndexArn": "arn:aws:dynamodb:ddblocal:000000000000:table/local/index/sortKeyIndex"
        }
    ]
}

我想像这样用Java查询它：

Index index = table.getIndex("sortKeyIndex");
ItemCollection<QueryOutcome> items2 = null;
QuerySpec querySpec = new QuerySpec();
querySpec.withKeyConditionExpression("sortKey > :end_date")
                .withValueMap(new ValueMap().withString(":end_date","2021-06-30T07:49:22.000Z"));
items2 = index.query(querySpec);

但是它抛出了一个“不支持查询键条件”的异常。我不明白这一点，因为在文档中，“<”运算符被描述为常规操作。谁能帮帮我

Answer 1

DDB Query() 需要一个键条件，其中包括对 hash/partition 键的相等性检查。

You must provide the name of the partition key attribute and a single value for that attribute. Query returns all items with that partition key value. Optionally, you can provide a sort key attribute and use a comparison operator to refine the search results.

换句话说，只有当你有一个复合主键（散列+排序）时，你才能真正使用 Query()。

如果没有将排序键指定为 table/GSI 的键的一部分，Query() 的行为就像 GetItem() 返回具有给定哈希键的单个记录。

查询 DynamoDb 全局二级索引

Query DynamoDb Global Secondary Index

java

amazon-web-services

amazon-dynamodb

aws-sdk