dynamodb scanexpression with scan filter in objective-c

Question

    AWSDynamoDBObjectMapper *dynamoDBObjectMapper = [AWSDynamoDBObjectMapper defaultDynamoDBObjectMapper];
    AWSDynamoDBScanExpression *scanExpression = [AWSDynamoDBScanExpression new];
    scanExpression.exclusiveStartKey = nil;
    scanExpression.limit = @20;
    [[[dynamoDBObjectMapper scan:[DDBTableRow class]
                      expression:scanExpression]
      continueWithExecutor:[BFExecutor mainThreadExecutor] withSuccessBlock:^id(BFTask *task) { ................

我能够扫描并返回从 DynamoDB 的特定表中记录的前 20 个，如上面的一段代码所示。

现在的问题是我想添加一个scanExpression.scanFilter =属性，但我还没有找到任何关于如何构建它的好方向。 我正在使用适用于 iOS AWSiOSSDKv2 的 aws 开发工具包xcode6

这是我到目前为止所拥有的。它尚未完成：

    AWSDynamoDBCondition *condition = [AWSDynamoDBCondition new];
    AWSDynamoDBAttributeValue *attribute = [AWSDynamoDBAttributeValue new];
    attribute.N = @"400";
    condition.comparisonOperator = AWSDynamoDBComparisonOperatorEQ;
    NSDictionary *scanFilter = @{@"lat":
                                     @{@"AttributeValueList":attribute,
                                       @"ComparisonOperator":@1}
                                 };
    scanExpression.scanFilter = scanFilter;

Answer 1

您可以按如下方式使用它：

AWSDynamoDBCondition *condition = [AWSDynamoDBCondition new];
AWSDynamoDBAttributeValue *attribute = [AWSDynamoDBAttributeValue new];
attribute.N = @"400";
condition.attributeValueList = @[attribute];
condition.comparisonOperator = AWSDynamoDBComparisonOperatorEQ;
scanExpression.scanFilter = @{@"lat": condition};