class AWS::DynamoDB
Provides a high-level interface for using DynamoDB
.
dynamo_db = AWS::DynamoDB.new( :access_key_id => '...', :secret_access_key => '...')
# Supported API Version
Please note, the ‘AWS::DynamoDB` classes have been built against the 2011-12-05 API version. Constructing a `AWS::DynamoDB` object with a newer API version will emit a warning and then ignore the specified version.
If you would like to use features of the newer 2012-08-10 API version, then please construct a DynamoDB
client and use the client API directly.
# supports the latest API version ddb = AWS::DynamoDB::Client.new(api_verison:'2012-08-10')
# 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
Constants
- IGNORING_API_SPECIFIED_MSG
Public Class Methods
AWS::Core::ServiceInterface::new
# File lib/aws/dynamo_db.rb, line 143 def initialize options = {} options = options.dup options[:dynamo_db] ||= {} warn(IGNORING_API_SPECIFIED_MSG) if options[:dynamo_db][:api_version] options[:dynamo_db][:api_version] = '2011-12-05' super(options) end
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]
# File lib/aws/dynamo_db.rb, line 184 def batch_get &block batch = BatchGet.new(:config => config) yield(batch) batch.to_enum(:each) end
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
# File lib/aws/dynamo_db.rb, line 223 def batch_write &block batch = BatchWrite.new(:config => config) yield(batch) batch.process! end
Returns a collection representing all the tables in your account.
@return [TableCollection]
# File lib/aws/dynamo_db.rb, line 154 def tables TableCollection.new(:config => config) end