= dm-adapter-simpledb

== What

A DataMapper adapter for Amazon's SimpleDB service. 

Features:
 * Uses the RightAWS gem for efficient SimpleDB operations.
 * Full set of CRUD operations
 * Supports nearly all DataMapper query predicates.
 * Full support for complex nested union, intersaction, and negation in queries
 * Migrations
 * DataMapper identity map support for record caching
 * Lazy-loaded attributes
 * DataMapper Serial property support via UUIDs.
 * Array properties
 * Basic aggregation support (Model.count("..."))
 * String "chunking" permits attributes to exceed the 1024-byte limit
 * Support for efficient :limit and :offset, for result set paging
 * Robust quoting of names in values in selects

Note: as of version 1.0.0, this gem supports supports the DataMapper 0.10.*
series and breaks backwards compatibility with DataMapper 0.9.*.

== Who

Originally written by Jeremy Boles. 

Contributers: 
  Edward Ocampo-Gooding (edward) 
  Dan Mayer (danmayer)
  Thomas Olausson (latompa)
  Avdi Grimm (avdi)


== Where

dm-adapter-simpledb is currently maintained by the Devver team and lives at:
http://github.com/devver/dm-adapter-simpledb/

== TODO

 * Handle exclusive ranges natively
   Implement as inclusive range + filter step
 * Tests for associations
 * Option for smart lexicographical storage for numbers
   - Zero-pad integers
   - Store floats using exponential notation
 * Option to store Date/Time/DateTime as ISO8601
 * Full aggregate support (min/max/etc)
 * Option to use libxml if available
 * Parallelized queries for increased throughput
 * Support of normalized 1:1 table:domain schemes that works with associations
 * Sharding
 * Support BatchPutAttributes
 * Silence SSL warnings
   See http://pivotallabs.com/users/carl/blog/articles/1079-standup-blog-11-24-2009-model-validations-without-backing-store-associations-to-array-and-ssl-with-aws
 * Token cache for reduced requests when given an offset
 * Optimize key queries

== Usage
  
=== Standalone
  
    require 'rubygems'
    require 'dm-core'
    require 'dm-adapter-simpledb'
    
    DataMapper.setup(:default, 
      :adapter       => 'simpledb',
      :access_key    => "ACCESS_KEY",
      :secret_key    => "SECRET_KEY",
      :domain        => "DOMAIN",
    )
    
    [Same as the following, but skip the database.yml]
    
=== In a Merb application
    See sample Merb application using Merb-Auth and protected resources on SimpleDB:
    http://github.com/danmayer/merb-simpledb-dm_example/tree/master
  
    Setup database.yml with the SimpleDB DataMapper adapter:

      adapter:    simpledb
      access_key: (a 20-character, alphanumeric sequence)
      secret_key: (a 40-character sequence)
      domain:     'my_amazon_sdb_domain'

    Create a model
  
      class Tree
        include DataMapper::Resource
      
        storage_name[:default] = "trees"
      
        property :id,   Serial
        property :name, String, :nullable => false
      end

    Use interactively (with merb -i)
  
    $ merb -i
  
      maple = Tree.new
      maple.name = "Acer rubrum"
      maple.save
    
      all_trees = Tree.all() # calls #read_all
      a_tree = Tree.first(:name => "Acer rubrum")
      yanked_tree = Tree.remote(:name => "Acer rubrum")

== Running the tests
   Add these two lines to your .bash_profile as the spec_helper relies on them

     $ export AMAZON_ACCESS_KEY_ID='YOUR_ACCESS_KEY'
     $ export AMAZON_SECRET_ACCESS_KEY='YOUR_SECRET_ACCESS_KEY'

   Configure the domain to use for integration tests. THIS DOMAIN WILL BE
   DELETED AND RECREATED BY THE TESTS, so do not choose a domain which contains
   data you care about.  Configure the domain by creating a file named
   THROW_AWAY_SDB_DOMAIN in the projet root:

    $ echo dm_simpledb_adapter_test > THROW_AWAY_SDB_DOMAIN

   Run the tests:
   
     rake spec

   NOTE: While every attempt has been made to make the tests robust, Amazon
   SimpleDB is by it's nature an unreliable service. Sometimes it can take a
   very long time for updates to be reflected by queries, and sometimes calls
   just time out. If the tests fail, try them again a few times before reporting
   it as a bug. Also try running the spec files individually.

== Bibliography

Relating to Amazon SimpleDB
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1292&ref=featured
Approaching SimpleDB from a relational database background
  
Active Record Persistence with Amazon SimpleDB
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1367&categoryID=152
  
Building for Performance and Reliability with Amazon SimpleDB
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1394&categoryID=152
  
Query 101: Building Amazon SimpleDB Queries
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1231&categoryID=152
  
Query 201: Tips & Tricks for Amazon SimpleDB Query
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1232&categoryID=152
Latter portion describes parallelization advantages of normalized domains – the
downside being the added complexity at the application layer (this library’s).
  
Using SimpleDB and Rails in No Time with ActiveResource
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1242&categoryID=152
Exemplifies using the Single Table Inheritance pattern within a single SimpleDB
domain by storing the model type in an attribute called '_resource' and using a
“SHA512 hash function on the request body combined with a timestamp and a
configurable salt” for the id.
  
RightScale Ruby library to access Amazon EC2, S3, SQS, and SDB
http://developer.amazonwebservices.com/connect/entry!default.jspa?categoryID=140&externalID=1014&fromSearchPage=true