range_key_sort_test.rb

require 'aws-sdk-core'
ddb = Aws::DynamoDB::Client.new(region: "ap-northeast-1")

table_name    = 'rangetest'
hash_key_str  = 'test'


(1...100).each do |i|
  ddb.put_item({
    table_name: table_name,
    item: {
      "group" => hash_key_str,
      "message_id" => i
    }
  })
end

# Descending
ddb.query({
  table_name: table_name,
  limit: 5,
  scan_index_forward:false,
  key_conditions: {
    "group" => { attribute_value_list: [hash_key_str], comparison_operator:"EQ"}
  }
}).items.each do |item|
  puts item["message_id"].to_i
end

# Ascending
ddb.query({
  table_name: table_name,
  limit: 5,
  scan_index_forward:true,
  key_conditions: {
    "group" => { attribute_value_list: [hash_key_str], comparison_operator:"EQ"}
  }
}).items.each do |item|
  puts item["message_id"].to_i
end