在objective-c中带有扫描过滤器的dynamodb scanexpression

问题描述

    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我的 DynamoDB 的特定表中记录的前 20 个，如上面的一段代码所示.

I am able to scan through and return the first 20 recorded from a specific table from my DynamoDB as shows on a piece of code above.

现在的问题是我想添加一个 scanExpression.scanFilter = 属性，但我还没有找到关于如何构建它的任何好的方向.我在 xcode6

The question now is I want to add a scanExpression.scanFilter = property but I haven't find any good direction on how to build that. I am using AWSiOSSDKv2 aws sdk for iOS on xcode6

这是我目前所拥有的.还没有完成:

here is what I have so far. It is not complete yet:

    AWSDynamoDBCondition *condition = [AWSDynamoDBCondition new];
    AWSDynamoDBAttributeValue *attribute = [AWSDynamoDBAttributeValue new];
    attribute.N = @"400";
    condition.comparisonOperator = AWSDynamoDBComparisonOperatorEQ;

    NSDictionary *scanFilter = @{@"lat":
                                     @{@"AttributeValueList":attribute,
                                       @"ComparisonOperator":@1}
                                 };
    scanExpression.scanFilter = scanFilter;

推荐答案

可以如下使用:

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

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