= Active OLAP

This Rails plugin makes it easy to add a basic OLAP interface to your application, which is 
great for administration interfaces. Its main uses are collection information about the
usage of your application and detecting inconsistencies and problems in your data.

This plugin provides:
* The main functions for OLAP querying: <tt>olap_query</tt> and <tt>olap_drilldown</tt>. These functions
  must be enabled for your model by calling <tt>enable_active_olap</tt> on your model class.
* Functions to easily define dimension, categories and aggregates to use in your
  OLAP queries.

In the future, the following functionality is planned to be included:
* A helper module to generate tables and charts for the query results. The gchartrb gem
  is needed for charts, as they are generated using the Google charts API.
* A controller that can be included in your Rails projects to get started quickly.

More information about the concepts and usage of this plugin, see the Active OLAP Wiki on
GitHub: http://wiki.github.com/wvanbergen/active_olap. I have blogged about this plugin 
on the Floorplanner tech blog: http://techblog.floorplanner.com/tag/active_olap/. Finally,
if you want to get involved or tinker with the code, you can access the repository at
http://github.com/wvanbergen/active_olap/tree.

== Why use this plugin?

This plugin simply runs SQL queries using the find-method of ActiveRecord. You might be 
wondering why you would need a plugin for that. 

First of all, it makes your life as a developer easier:
* This plugin generates the nasty SQL expressions for you using standard compliant SQL, 
  handles issues with SQL NULL values and makes sure the results have a consistent format.
* You can define dimensions and aggregates that are "safe to use" or known to yield useful
  results. Once dimensions and aggregates are defined, they can be combined at will safely 
  and without any coding effort, so it is suitable for management. :-)

== Installation

To install the gem on your system, run: 

  gem install active_olap -s http://gemcutter.org

Alternatively, you can include them gem into your Rails project by adding it to
the configuration in your <tt>environment.rb</tt> file:

  gem.config 'active_olap', :source => 'http://gemcutter.org'

==  Requirements

This plugin is usable for any ActiveRecord-based model. Because <tt>named_scope</tt> is used for the 
implementation, Rails 2.1 is required for it to work. It is tested to work with MySQL 5 and
SQLite 3 but should work with other databases as well, as it only generates standard 
compliant SQL queries.

<b>Warning:</b> OLAP queries can be heavy on the database. They can impact the performance of your
application if you perform them on the same server or database. Setting good indices is 
helpful, but it may be a good idea to use a copy of the production database on another 
server for these heavy queries.

<b>Another warning:</b> while this plugin makes it easy to perform OLAP queries and play around
with it, interpreting the results is hard and mistakes are easily made. At least, make sure
to validate the results before they are used for decision making.

== About this plugin

The plugin is written by Willem van Bergen for Floorplanner.com. It is MIT-licensed (see 
MIT-LICENSE).

* The Floorplanner techblog contains some posts about this plugin that can be used as a reference: http://techblog.floorplanner.com/tag/active_olap
* The project wiki also contains some documentation: http://wiki.github.com/wvanbergen/active_olap

If you have any questions or want to help out with the development of this plugin,
please contact me on my github account.