Adding an array of an array at Amazon DynamoDB

Question

I know that AmazonDB supports number, string, number set and string set as item types. But, how about a set of an string set (array of array, or multidimensional array)?

In case it's possible, this is the only way I found to do that, which didn't work (using PHP):

$units_frequencies["id"][0] = "400";
$units_frequencies["id"][1] = "401";
$units_frequencies["id"][2] = "402";
$units_frequencies["frequency"][0] = "20";
$units_frequencies["frequency"][1] = "30";
$units_frequencies["frequency"][2] = "50";

// item that will be inserted
$item = array(
    'id' => array(AmazonDynamoDB::TYPE_STRING => $id), 
    'arrays_field' => array(
        AmazonDynamoDB::TYPE_ARRAY_OF_STRINGS => array(
            AmazonDynamoDB::TYPE_ARRAY_OF_STRINGS => $units_frequencies)));

I don't want to have two columns (one for $units_frequencies["id"] and $units_frequencies["frequency"]) because the second one can have two index with the same values, which is not allowed by Dynamo.

Thanks in advance.

Sorry, forgot to paste the error returned by DynamoDB (in case it helps): [body] => CFSimpleXML Object ( [__type] => com.amazon.coral.service#SerializationException [Message] => Start of structure or map found where not expected. ) — DMerliMorais
– DMerliMorais, Commented Mar 2, 2012 at 18:15

Chen Harel · Accepted Answer · 2012-03-19 17:44:50Z

1

It doesn't.
At least while looking at AttributeValue.class (AWS Java SDK)
I also couldn't find any hint on the documentation site except for those dealing with int, string, set of string or set of int

answered Mar 19, 2012 at 17:44

Chen Harel

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2 Comments

DMerliMorais Over a year ago

You're right. I got rid of my problem by using a set of strings, on which each one of the indexes have the ID and frequency like that: 400#20, 401#30 and 402#50.

Chen Harel Over a year ago

Great! If you believe an answer is correct, please mark it as one.

Alex R. R. · Accepted Answer · 2013-08-26 17:05:42Z

0

You can eventually serialize your object. More info at https://java.awsblog.com/post/Tx1K7U34AOZBLJ2/Using-Custom-Marshallers-to-Store-Complex-Objects-in-Amazon-DynamoDB

answered Aug 26, 2013 at 17:05

Alex R. R.

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