class AWS::DynamoDB

Provides a high-level interface for using DynamoDB.

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

# 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", 10, 5,
  :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

@!attribute [r] client

@return [Client] the low-level DynamoDB client object

Public Class Methods

new(options = {}) click to toggle source
Calls superclass method AWS::Core::ServiceInterface.new
# File lib/aws/dynamo_db.rb, line 129
def initialize options = {}
  options = options.dup
  options[:dynamo_db] ||= {}
  options[:dynamo_db][:api_version] = '2011-12-05'
  super(options)
end

Public Instance Methods

batch_get() { |batch| ... } click to toggle source

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]

# File lib/aws/dynamo_db.rb, line 169
def batch_get &block
  batch = BatchGet.new(:config => config)
  yield(batch)
  batch.to_enum(:each)
end
batch_write() { |batch| ... } click to toggle source

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 AWS::DynamoDB::BatchWrite#process!)

@see BatchWrite @see AWS::DynamoDB::BatchWrite#put @see AWS::DynamoDB::BatchWrite#delete @see AWS::DynamoDB::BatchWrite#write

# File lib/aws/dynamo_db.rb, line 208
def batch_write &block
  batch = BatchWrite.new(:config => config)
  yield(batch)
  batch.process!
end
tables() click to toggle source

Returns a collection representing all the tables in your account.

@return [TableCollection]

# File lib/aws/dynamo_db.rb, line 139
def tables
  TableCollection.new(:config => config)
end