Class AWS::DynamoDB
In: lib/aws/dynamo_db.rb
lib/aws/dynamo_db/attribute_collection.rb
lib/aws/dynamo_db/batch_get.rb
lib/aws/dynamo_db/table.rb
lib/aws/dynamo_db/primary_key_element.rb
lib/aws/dynamo_db/errors.rb
lib/aws/dynamo_db/item.rb
lib/aws/dynamo_db/expectations.rb
lib/aws/dynamo_db/keys.rb
lib/aws/dynamo_db/types.rb
lib/aws/dynamo_db/item_data.rb
lib/aws/dynamo_db/request.rb
lib/aws/dynamo_db/item_collection.rb
lib/aws/dynamo_db/batch_write.rb
lib/aws/dynamo_db/client.rb
lib/aws/dynamo_db/table_collection.rb
lib/aws/dynamo_db/resource.rb
Parent: Object

Provides a high-level interface for using DynamoDB.

  dynamo_db = AWS::DynamoDB.new(
    :access_key_id => '...',
    :secret_access_key => '...',
    :session_token => '...')

Credentials

Amazon DynamoDB requires that all requests are made with short-term credentials (e.g. requires a session token).

@note If you make a request using AWS::DynamoDB with long-term credentials

  a request is made to Amazon STS for temproary session credentials.
  These will be cached in the process and re-used.

Tables

Tables contain items, and organize information into discrete areas. All items in the table have the same primary key scheme. You designate the attribute name (or names) to use for the primary key when you create a table, and the table requires each item in the table to have a unique primary key value. The first step in writing data to DynamoDB is to create a table and designate a table name with a primary key.

  table = dynamo_db.tables.create(
    "MyTable",
    :hash_key => { :id => :string }
  )
  sleep 1 while table.status == :creating

See {Table} and {TableCollection} for more information on creating and managing tables.

Items and Attributes

An item is a collection of one or more attributes, where each attribute has a string name and a string, number, string set or number set value.

The identity of an item consists of its hash key value and — if the table‘s schema includes a range key — its range key value.

  item = table.items.put(:id => "abc123")
  item.hash_value # => "abc123"
  item.attributes.set(
    :colors => ["red", "blue"],
    :numbers => [12, 24]
  )

See {Item} and {ItemCollection} for more information on creating and managing items. For more information on managing attributes, see {AttributeCollection}.

Examples

  # create a table (10 read and 5 write capacity units) with the
  # default schema (id string hash key)
  dynamo_db = AWS::DynamoDB.new
  table = dynamo_db.tables.create('my-table', 10, 5)

  sleep 1 while table.status == :creating
  table.status #=> :active

  # get an existing table by name and specify its hash key
  table = dynamo_db.tables['another-table']
  table.hash_key = [:id, :number]

  # add an item
  item = table.items.create('id' => 12345, 'foo' => 'bar')

  # add attributes to an item
  item.attributes.add 'category' => %w(demo), 'tags' => %w(sample item)

  # update an item with mixed add, delete, update
  item.attributes.update do |u|
    u.add 'colors' => %w(red)
    u.set 'category' => 'demo-category'
    u.delete 'foo'
  end

  # delete attributes
  item.attributes.delete 'colors', 'category'

  # get attributes
  item.attributes.to_h
  #=> {"id"=>#<BigDecimal:10155f5d0,'0.12345E5',9(18)>, "tags"=>#<Set: {"item", "sample"}>}

  # delete an item and all of its attributes
  item.delete

Methods

Included Modules

Core::ServiceInterface

Classes and Modules

Module AWS::DynamoDB::Errors
Module AWS::DynamoDB::Expectations
Module AWS::DynamoDB::Keys
Module AWS::DynamoDB::Types
Class AWS::DynamoDB::AttributeCollection
Class AWS::DynamoDB::BatchGet
Class AWS::DynamoDB::BatchWrite
Class AWS::DynamoDB::Client
Class AWS::DynamoDB::Item
Class AWS::DynamoDB::ItemCollection
Class AWS::DynamoDB::ItemData
Class AWS::DynamoDB::PrimaryKeyElement
Class AWS::DynamoDB::Request
Class AWS::DynamoDB::Resource
Class AWS::DynamoDB::Table
Class AWS::DynamoDB::TableCollection

Public Instance methods

Request attributes for items spanning multiple tables. You configure you batch get request using a block:

  attributes = dynamo_db.batch_get do |batch|
    # call methods on batch specify tables, attributes and items
    # ...
  end

The value returned by batch_get is an enumerable object that yields the table name (as a string) and a hash of attributes. The enumerable yields once per item received in the batch get.

Configuring the batch

You can call two methods on the yielded batch object:

  • table
  • items

For more information on these methods, see {BatchGet}.

@yield [String, Hash] Yields the table name as a string and a hash

  of attributes for each item received in the bach get request.

@return [Enumerable]

Yields a batch for writing (put and delete) items across multiple tables. You can put and delete items in the same batch.

@example Putting items across tables

  # shard data across two tables with batch write
  items = [
    { :id => '123', :color => 'red' },
    { :id => '456', :color => 'blue' },
    { :id => '789', :color => 'green' },
  ]

  ddb.batch_write do |batch|
    batch.put('table1', items)
    batch.put('table2', items)
  end

@example Mixing puts and deletes

  ddb.batch_write do |batch|
    batch.write('table1', :put => [...], :delete => [...])
    batch.write('table2', :put => [...], :delete => [...])
  end

@yield [BatchWrite]

@return (see BatchWrite#process!)

@see BatchWrite @see BatchWrite#put @see BatchWrite#delete @see BatchWrite#write

Returns a collection representing all the tables in your account.

@return [TableCollection]

[Validate]