Question

What is the best way to check if table exists in DynamoDb?

I would appreciate it if the code would be in PHP.

Either active or not.

* Added later as an example to various cases for error code 400

It’s very easy to check if the table exist, it can have one of the following
TableStatus => CREATING, ACTIVE, DELETING or UPDATING

but in case i get error 400 it can mean more than one thing.

1) sent null string as a table name by mistake.

[x-aws-body] => {“TableName”:””}
)

[body] => CFSimpleXML Object
    (
        [__type] => com.amazon.coral.validate#ValidationException
        [message] => The paramater 'tableName' must be at least 3 characters long and at most 255 characters long
    )

[status] => 400

2) syntax error in the command sent to DynamoDB, for example writting tabel_name instead of table_name.

[x-aws-body] => {“TabelName”:”test7″}
)

[body] => CFSimpleXML Object
    (
        [__type] => com.amazon.coral.validate#ValidationException
        [message] => The paramater 'tableName' is required but was not present in the request
    )

[status] => 400

3) I would guess but didn’t check, if I exceed at that same time the provisioned capacity on the table.

Answer 1

You can have a look at “describe_table” of the official PHP SDK. 400 means “does not exist” There is a pretty extensive example in the official documentation. Look at how it is used in the “delete” example, right at the bottom.

http://docs.amazonwebservices.com/amazondynamodb/latest/developerguide/LowLevelPHPTableOperationsExample.html

Here is the (stripped) example from the doc

<?php
require_once dirname(__FILE__) . '/sdk/sdk.class.php';

$dynamodb = new AmazonDynamoDB();
$table_name = 'ExampleTable';
$response = $dynamodb->describe_table(array('TableName' => $table_name));

if((integer) $response->status !== 400)
{
    $error_type = $response->body->__type;
    $error_code = explode('#', $error_type)[1];
    if($error_code == 'ResourceNotFoundException')
    {
        echo "Table ".$table_name." exists.";
    }
}
?>