Rails - Mar 2006 - Ackbar 0.1.1 - ActiveRecord Adapter for KirbyBase

Hi All,

= What''s New

This is a bug fix release. Jamey Cribbs (author of KirbyBase) has run
through Active Web Development with Rails, building the Depot sample
app on top of Akbar/KirbyBase. A few issues uncovered there were fixed
/ enhanced in this release. See the CHANGELOG for full details.

You can read all about his exercise, starting at
http://houseonfire.wordpress.com/2006/02/18/hello-world/.

= About Ackbar

Ackbar is an adapter for ActiveRecord (the Rails ORM layer) to the KirbyBase
pure-ruby plain-text DBMS. Because KirbyBase does not support SQL, joins or
transactions, this is not a 100% fit. There are some changes to the ActiveRecord
interface (see below), but it may still be useful in some cases.

= URIs

Ackbar: http://ackbar.rubyforge.org
KirbyBase: http://www.netpromi.com/kirbybase_ruby.html
Rails: http://www.rubyonrails.com
Pimki: http://pimki.rubyforge.org

= Goals

Ackbar''s project goals, in order of importance, are:
1. Support Pimki with a pure-ruby, cross-platform hassle-less install DBMS
2. An exercise for me to learn ActiveRecord inside out
3. Support other "shrink-wrapped" Rails projects with similar needs

As can be seen, the main reason I need Ackbar is so I distribute Pimki across
multiple platforms without requiring non-Ruby 3rd party libraries.
KirbyBase will work wherever Ruby works, and so will Pimki. That alleviates
the need to repackage other bits, end users will not have to install extra
software, I have full control on the storage, the storage is in plain text.
Just what I need to "shrink wrap" a Rails project for end-user
distribution.

= What''s Covered

Ackbar currently passes through a small bootstrap test suite, and through about
80% of the ActiveRecord test suite. I will never pass 100% of the tests because
KirbyBase does not support all required functionality.

Ackbar includes a SQL fragment translator, so that simple cross-database code
should be maintainable. For example the following will work as expected,
  Book.find :all, :conditions => "name =
''Pickaxe''"
  Book.find :all, :conditions => ["name = ?",
''Pickaxe'']
Additionally, you can also provide blocks:
  Book.find :all, :conditions => lambda{|rec| rec.name ==
''Pickaxe''}
or even:
  Book.find(:all) {|rec| rec.name == ''Pickaxe''}

Most of these changes are around the #find method, bit some apply to #update and
associations. Basic SQL translation should work the same, but you can always
provide custom code to be used. See the CHANGELOG and the tests for examples.


= What''s Not Covered

* Transactions
* Joins, and therefore Eager Associations
* Mixins
* Other plugins

On the todo list is support for mixins. It might even be possible to
rig something to simulate joins and eager associations, but that is
for a later stage. Transactions will obviously only be supported once
they are supported by KirbyBase.

Additionally, there are numerous little changes to the standard behaviour. See
the CHANGELOG and the tests for more details. These may cause little
heart attacks if you expect a standard SQL database.

It is also worth noting that other plugins that write SQL will not
work. You will need to get a copy of them to your /vendors dir and
modify the relevant parts.

= Installation

Simply:
  gem install ackbar
or download the zip file from http://rubyforge.org/projects/ackbar and
just stick kirbybase_adapter.rb in the Rails lib dir.

You will then need to add
 require ''kirbybase_adapter''
in the config/environment.rb file of your project.

If you plan on multi-database development / deployment, you must
require the adapter only if necessary:
 require ''kirbybase_adapter'' if
ActiveRecord::Base.configurations[RAILS_ENV][''adapter''] ==
''kirbybase''

This is because Ackbar overrides certain methods in ActiveRecord::Base
and others. These methods translate the standard SQL generation to method
calls on KirbyBase, and obviously should not be overridden for regular DBs.


Please do not hesitate to contact me for questions, comments, whacks
on the head with a clue stick :-)

Cheers,
Assaph