当使用排序键作为filterExpression时,为什么AWSDynamodBCanExpression返回空?

BoardId   |  DateTime          |  Data  |  Type
-------------------------------------------------
1         |  20180424T123508Z  |  68.1  |  U
1         |  20181026T143233Z  |  38.2  |  T
1         |  20190108T120150Z  |  38.1  |  T
2         |  20180425T092311Z  |  63.4  |  U

分区密钥 “DateTime”是 排序键 .

我曾经 AWSDynamoDBObjectMapper#scan 要执行此操作,请使用以下代码:

    let dbObjMapper = AWSDynamoDBObjectMapper.default()

    let scanExpression = AWSDynamoDBScanExpression()
    scanExpression.limit = 10
    scanExpression.filterExpression = "#id = :id AND contains(#dt, :dt)"
    scanExpression.expressionAttributeNames = [
        "#id" : "BoardId",
        "#dt" : "DateTime"
    ]
    scanExpression.expressionAttributeValues = [
        ":id" : "1",
        ":dt" : "2019"
    ]

    dbObjMapper
        .scan(Event.self, expression: scanExpression)
        .continueWith(block: {
            (task: AWSTask<AWSDynamoDBPaginatedOutput>!) -> Any? in
            if let error = task.error as NSError? {
                print("The request failed. Error: \(error)")
            } else if let paginatedOutput = task.result {
                print("The request was successful.")
                print(paginatedOutput.items.count)
                for event in paginatedOutput.items as! [Event] {
                    print(event)
                }
            }
            return ()
    })

但是我得到了一个空的结果。没有错误(“ 请求成功。 )但打印 paginatedOutput.items.count

我的英语怎么了 AWSDynamoDBScanExpression

我尝试使用其他扫描配置:

• filterExpression 好啊 ,最多可返回10项
• #id = :id 好啊 ,返回最多10个BoardId为1的项目
• contains(#dt, :dt) =>没有错误,但也返回空结果
• 设定 scanExpression.indexName 到某个索引,其中“DateTime” 排序键(例如“BoardId”)是 分区密钥 排序键 )=> 好啊

报纸上没有提到这一点 AWS SDK for iOS docs 或者在 AWS Working with Scan docs 使用Scan,您可以在筛选器表达式中指定任何属性,包括分区键和排序键属性 ")