MultiConditions is a simple ActiveRecord plugin for storing ActiveRecord query conditions and make complex queries painless.
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.
conditions = MultiConditions.new # ... do some elaboration conditions.append_condition(['active = ? AND query LIKE ?', true, '%foo'] # ... other elaboration conditions.append_condition(['name = ?', 'aname'] conditions.to_conditions # => "active = true AND query LIKE '%foo' AND name = 'aname'"
ActiveRecord 2.0 (or greater)
If you want to run the test suite:
MultiConditions source code is managed via GIT and hosted at GitHub: github.com/weppos/activerecord-multiconditions/.
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.
gem 'activerecord-multiconditions' require 'multi_conditions'
Now MultiConditions object is automatically available as subclass of any ActiveRecord object.
class Task < ActiveRecord::Base; end multiconditions = Task::Multiconditions.new # => new instance
As stated by the Important section above, you first need a valid ActiveRecord model to create a MultiConditions instance. Because MultiConditions helps you to deal with ActiveRecord queries, it's easy to understand why you MUST establish a valid database connection and have at least one table (mapped with a Model) to query.
If you use ActiveRecord from Rails, this is just a matter of creating a new Model.
# create the Task model class Task < ActiveRecord::Base end
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.new(:foo => 'bar') Task.find(:all, c.to_conditions) end end
But you can also create a new instance from an other library, class or model. Just remember to initialize MultiConditions from its own namespace.
class Foo class << self def my_cool_conditions Task::MultiConditions.new(:foo => 1).to_conditions end end end Foo.my_cool_conditions # => 'foo = 1'
You can append new conditions calling
and passing the conditions you want to append or prepend. See Condition Types section to lean more about supported objects.
conditions = MultiConditions.new conditions.append_condition(['active = ? AND query LIKE ?', true, '%foo'] conditions.prepend_condition(['name = ?', 'aname'] conditions.to_conditions # => "name = 'aname' AND active = true AND query LIKE '%foo'"
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 = MultiConditions.new conditions.append_conditions(:foo => 1, :bar => 2) conditions.append_conditions('active = 1') conditions.append_conditions(['name LIKE ?', '%foo']) conditions.to_conditions # => '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 become part of ActiveRecord package and creates its own namespace at ActiveRecord::Base::MultiConditions.
For various reason, you cannot initialize a new ActiveRecord::Base::MultiConditions but you MUST initialize a MultiConditions instance from a Model.
# The wrong way # raises Message: <"undefined method `abstract_class?' for Object:Class"> ActiveRecord::Base::MultiConditions.new # The right way class Model < ActiveRecord::Base def a_method() c = MultiConditions.new find(:all, :conditions => c.to_conditions) end end
Simone Carletti <email@example.com>
If you like this software, please recommend me at Working with Rails.
Feel free to email Simone Carletti with any questions or feedback.
Please submit your bug reports to the Redmine installation for MultiConditions available at code.simonecarletti.com/activerecord-multiconditions.
See CHANGELOG file.