AWS ruby sdk v2 - dynamodb query

Question

I've got a hash (string) and range (number) table in DynamoDB. I'm trying to run a query using the ruby SDK v2.0.30 but keep getting the following error:

aws-sdk-core-2.0.30/lib/seahorse/client/plugins/raise_response_errors.rb:15:in `call': One or more parameter values were invalid: Condition parameter type does not match schema type (Aws::DynamoDB::Errors::ValidationException)

Here is my code:

gem 'aws-sdk', '~> 2'
require 'aws-sdk'

dynamodb = Aws::DynamoDB::Client.new(region: 'eu-west-1', credentials: creds)
resp = dynamodb.query(
      table_name: "TEST_TABLE",
      key_conditions: {
        'ID' => {
          comparison_operator: 'EQ',
          attribute_value_list: [{ 's' => 'test123' }]
        }
      })

I'm new to ruby and have tried looking online and on AWS docs but can't find anything. Any help would be appreciated.

Thanks

Answer 1

Your error is in how you formatted the value of the hash key in your query expression. The v2 AWS SDK for Ruby ( aws-sdk gem) accepts all attribute values as vanilla Ruby values.

A value can be:

• String
• Numeric (Integer, Float, BigDecimal, etc)
• Boolean
• IO (blob type)
• Set (of Numeric/String)
• Array (of values )
• Hash (String => value )

You do not need to provide the type hint as was required with the v1 AWS SDK for Ruby.

ddb = Aws::DynamoDB::Client.new
ddb.query({
  table_name: 'TEST_TABLE',
  key_conditions: {
    'ID' => {
      comparison_operattor: 'EQ',
      attribute_value_list: ['test-123']      
    }
  }
})

Also, not directly related to you question, but you may find the following blog series helpful when working with DynamoDB from the aws-sdk gem:

• part 1 - projection expressions
• part 2 - condition expressions
• part 3 - update expressions