PHP AWS DynamoDB: Limit the Number of Total Query Results Using an Iterator

Question

I am trying to limit the total number of results that can return with an iterator to 3. Not the number of results for each iteration. I hope to make this number dynamic. However, I cannot find a real answer to accomplish this, and the documentation provided by AWS will not help. Placing a limit inside an array with a table name and keys does not limit the results. I also put it in my own separate array, but that doesn't work either. Below I tried, but I could not get this to work. Any help would be greatly appreciated.

$iterator = $dbh->getIterator('Query', array( 'TableName' => 'raw', 'KeyConditions' => array( 'deviceID' => array( 'AttributeValueList' => array( array('S' => $deviceID) ), 'ComparisonOperator' => 'EQ' ) ), 'ScanIndexForward' => false // true = ascending, false = descending ), array( 'Limit' => 3 ) ); 

Then put the received data into an array. I don’t know if I need to change anything here?

 foreach ($iterator as $item) { array_push($resultArray, $item); } 

Answer 1

You may have already tried this by looking at it, but try your code with the lowercase "limit".

  $iterator = $dbh->getIterator('Query', array( 'TableName' => 'raw', 'KeyConditions' => array( 'deviceID' => array( 'AttributeValueList' => array( array('S' => $deviceID) ), 'ComparisonOperator' => 'EQ' ) ), 'ScanIndexForward' => false // true = ascending, false = descending ), array( 'limit' => 3 ) ); 

You can also try to limit by doing below.

 foreach (new LimitIterator($iterator, 0, 3) as $item) { array_push($resultArray, $item); } 

Answer 2

Try it. It sets Limit once inside params, which should limit the results of the query, and then once outside the parameters, which should limit the size of the iterator

 $iterator = $dbh->getIterator('Query', array( 'TableName' => 'raw', 'KeyConditions' => array( 'deviceID' => array( 'AttributeValueList' => array( array('S' => $deviceID) ), 'ComparisonOperator' => 'EQ' ) ), 'ScanIndexForward' => false, // true = ascending, false = descending 'Limit' => 3 ), array( 'limit' => 3, 'page_size' => 3 ) ); 

Make sure that the argument outside the parameters is the "limit" (lowercase), and inside the "Limit" (starts with capital).