= dm-adapter-simpledb
This is the new version of the adapter now based on Right_Aws which has helped a lot with performance. The rest of this FAQ is a bit dated...
Written by Jeremy Boles
Contributers Edward Ocampo-Gooding, Dan Mayer
A DataMapper adapter for SimpleDB.
This version combines elements of Jeremy's orginal project, adding in code from Edward Ocampo-Gooding. It also includes various bug fixes and updates from Dan Mayer.
Tested using Matthew Painter’s SimpleDB/dev http://code.google.com/p/simpledb-dev/
Additional SimpleDB/dev setup notes found here: http://pandastream.tumblr.com/post/52779609/playing-with-panda-without-simpledb-account
== Current state
Updated to work with current versions of DataMapper and Merb, in use on small production sites.
When starting this project, I assumed that SimpleDB allowed queries to span more than one domain. I was terribly wrong.
In lieu of that, this SimpleDB adapter follows the Single Table Inheritance pattern espoused by articles online and seen in a variety of similar libraries (see Bibliography). What a bummer.
== Future goals
* Parallelized queries for increased throughput
* Support of normalized 1:1 table:domain schemes that works with associations
* Local caching of results using something like query strings for cache keys
== Usage
=== Standalone
require 'rubygems'
require 'dm-core'
DataMapper.setup(:default, 'simpledb://sdb.amazon.com/sweetapp_development', :access_key_id => 'a valid access key id', :secret_access_key => 'a valid secret access key id')
[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
database: 'default'
access_key_id: (a 20-character, alphanumeric sequence)
secret_access_key: (a 40-character sequence)
domain: 'sweetapp_development'
base_url: 'http://sdb.amazon.com'
Alternatively,
Create a model
class Tree
include DataMapper::Resource
storage_name "trees" # manually setting the domain
property :id, Integer, :serial => true
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'
Create the test domain on SimpleDB, :domain => 'missionaries' as found in spec_helper. This can be done easiest via IRB or I went to a project that had a database.yml and called db:automigrate because of the added migration support to this adaprter.
rake spec
== 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
