Reserved Words in DynamoDB using AWS SDK PHP

Question

I am using batchGetItem method to retrieve x of items and using ProjectionExpression to retrieve x attributes of each item.

$result = $client->batchGetItem(array(
    'RequestItems' => array(
        $table => array(
            'Keys' => $keys,
            'ConsistentRead' => true,
            'ProjectionExpression' => "id, name"
        ),
    ),
));
$read_items = $result->getPath("Responses/{$table}");

However some of my items have attributes such as name and token which are reserved words in DynamoDB.

http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html

{"__type":"com.amazon.coral.validate#ValidationException","message":"Invalid ProjectionExpression: Attribute name is a r (truncated...)
 ValidationException (client): Invalid ProjectionExpression: Attribute name is a reserved keyword; reserved keyword: name - {"__type":"com.amazon.coral.validate#ValidationException","message":"Invalid ProjectionExpression: Attribute name is a reserved keyword; reserved keyword: name"}
Filename:    /var/app/vendor/aws/aws-sdk-php/src/WrappedHttpHandler.php

As far I understand expression attribute name is the soultion for this, but I am struggling to find the way to do it batchGetItem, can someone please give a small example how to do it using SDK PHP version 3.20.11 ?

notionquest notionquest · Accepted Answer · 2017-09-19T14:38:49

Here is an example for ExpressionAttributeNames.

"#name" - is the placeholder for attribute name and the actual attribute name is replaced by the value in ExpressionAttributeNames.

$result = $client->batchGetItem(array(
    'RequestItems' => array(
        $table => array(
            'Keys' => $keys,
            'ConsistentRead' => true,
            'ProjectionExpression' => "id, #name",
            'ExpressionAttributeNames' => array('#name' => 'name'}
        ),
    ),
));

Refer link

Reserved Words in DynamoDB using AWS SDK PHP

1 Answers