Class: ActiveRecord::Base::MultiConditions

Inherits:
Object
  • Object
show all
Defined in:
lib/multi_conditions.rb

Overview

ActiveRecord::MultiConditions

MultiConditions is a simple ActiveRecord plugin for storing ActiveRecord query 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'"

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.

Important

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

Defined Under Namespace

Modules: Version

Constant Summary collapse

NAME = 
'ActiveRecord::MultiConditions'
GEM = 
'activerecord-multiconditions'
AUTHOR = 
'Simone Carletti <[email protected]>'
VERSION = 
defined?(Version) ? Version::STRING : nil
STATUS = 
'alpha'
BUILD = 
''.match(/(\d+)/).to_a.first

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(condition = nil) {|_self| ... } ⇒ MultiConditions

Creates a new MultiConditions instance and initializes it with conditions.

# empty instance
c = MultiConditions.new

# new instance with a first value
c = MultiConditions.new(['condition = ?', 'value'])

# initialization with block
c = MultiConditions.new do |condition|
  condition.append_condition('foo = 1')
  condition.append_condition('bar = 2')
  condition.append_condition(:baz => 3)
end

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/multi_conditions.rb', line 113

def initialize(condition = nil, &block) # :yields: self
  @conditions = []
  append_condition(condition)
  yield(self) if block_given?
  self
end

Instance Attribute Details

#conditions ⇒ Object (readonly)

Conditions collection



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# File 'lib/multi_conditions.rb', line 95

def conditions
  @conditions
end

Instance Method Details

#append_condition(condition) ⇒ Object

Appends a new condition at the end of condition list.



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# File 'lib/multi_conditions.rb', line 123

def append_condition(condition)
  @conditions.push(prepare_condition(condition))    unless condition.nil?
end

#prepend_condition(condition) ⇒ Object

Prepends a new condition at the beginning of condition list.



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# File 'lib/multi_conditions.rb', line 130

def prepend_condition(condition)
  @conditions.unshift(prepare_condition(condition)) unless condition.nil?
end

#to_conditions ⇒ Object Also known as: to_s

Returns a :conditions suitable representation of this object

c = MultiConditions.new do |condition|
  condition.append_condition('foo = 1')
  condition.append_condition('bar = 2')
  condition.append_condition(:baz => 3)
end

c.to_conditions
# => 'foo = 1 AND bar = 2 AND baz = 3'

# Example usage
find(:all, :conditions => c.to_conditions)



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# File 'lib/multi_conditions.rb', line 149

def to_conditions
  @conditions.join(' AND ')
end