weppos edited this page Oct 6, 2010 · 3 revisions
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MultiConditions is a simple ActiveRecord plugin for storing ActiveRecord find conditions and make complex queries painless.

DISCONTINUED PROJECT: as of April 2009, I decided to discontinue the development of this library to concentrate my efforts on other projects.
If you are looking for a good alternative, I encourage you to have a look at Ben Johnson’s SearchLogic library. SearchLogic provides all ActiveRecord::Multiconditions features and many other cool stuff.


This plugin doesn’t replace ActiveRecord#with_scope method, nor the basic :condition usage but extends it with the ability of storing illimitate conditions in multiple step.

class Task < ActiveRecord::Base; end

# create a new MultiConditions instance
conditions = Task.multicondition

# append a condition
conditions.append_condition(['active = ? AND query LIKE ?', true, '%foo'])

# conditional-append a condition 
conditions.append_condition(['name = ?', 'aname']) if admin?

# get the final condition list ...
# => "active = true AND query LIKE '%foo' AND name = 'aname'"

# ... compatible with ActiveRecord finders
Task.find(:all, :conditions => conditions.to_conditions)


  • Ruby 1.8.6
  • ActiveRecord >= 2.0 (tested up to AR 2.3)

If you want to run the test suite:

  • sqlite3-ruby

Download and Installation

Installing ActiveRecord MultiConditions as a GEM is probably the best and easiest way. You must have RubyGems installed for the following instruction to work:

$ sudo gem install activerecord-multiconditions

To install the library manually grab the source code from the website, navigate to the root library directory and enter:

$ sudo ruby setup.rb

If you need the latest development version you can download the source code from the GIT repositories listed above. Beware that the code might not as stable as the official release.


First, don’t forget to require the library.

require 'rubygems'
require 'activerecord-multiconditions'

Now MultiConditions object is automatically available as subclass of any ActiveRecord object.

class Task < ActiveRecord::Base
  # your Task model

multiconditions = Task.multiconditions(:status => 'active')
# => new instance

Creating a new instance

If you use ActiveRecord from Rails, this is just a matter of creating a new Model.

# create the Task model
class Task < ActiveRecord::Base

Now MultiConditions is automatically available within your Task namespace.
You can use it in whatever class method, for example:

class Task < ActiveRecord::Base
  def complex_search()
    c = multiconditions(:foo => 'bar')
    Task.find(:all, c.to_conditions)


But you can create a new instance from an other library, class or model as well.
Just remember to initialize MultiConditions from its own namespace.

class Foo
  class << self
    def my_cool_conditions
      Task::multiconditions(:foo => 1).to_conditions

# => 'foo = 1'

Appending conditions

You can append new conditions with the following methods, passing the conditions you want to append or prepend as parameters.

  • #append_condition
  • #prepend_condition

See Condition Types section to lean more about supported objects.

conditions.append_condition(['active = ? AND query LIKE ?', true, '%foo']
conditions.prepend_condition(['name = ?', 'aname']
# => "name = 'aname' AND active = true AND query LIKE '%foo'"

Condition types

The MultiConditions object accepts any type of conditions supported by ActiveRecord, including Strings, Arrays and Hashes, and merges them alltogether just before sending the final :condition value to ActiveRecord search method.

conditions.append_conditions(:foo => 1, :bar => 2)
conditions.append_conditions('active = 1')
conditions.append_conditions(['name LIKE ?', '%foo'])

# => 'foo = 1 AND :bar = 2 AND active = 1 AND name LIKE '%foo'

See ActiveRecord::Base#find documentation for more conditions examples.


Once loaded, this library becomes part of ActiveRecord package and it creates its own namespace at ActiveRecord::Base::MultiConditions.

require 'multi_conditions'

For various reason, you cannot initialize a new ActiveRecord::Base::MultiConditions but you MUST initialize a MultiConditions instance from a Model or using ActiveRecord::Base#multiconditions method (preferred way).

# The wrong way
# raises Message: <"undefined method `abstract_class?' for Object:Class">

# The right way
class Model < ActiveRecord::Base
  def a_method()
    c = MultiConditions.new(Model, ['foo = ?', 'bar'])
    find(:all, :conditions => c.to_conditions)

# The best way
class Model < ActiveRecord::Base
conditions = Model.multiconditions(['foo = ?', 'bar'])



FeedBack and Bug reports

Feel free to email me with any questions or feedback.
Please use the Ticket System to submit bug reports or feature request.


See the CHANGELOG.rdoc file for details.


Copyright © 2008-2009 Simone Carletti, ActiveRecord::MultiConditions is released under the MIT license.