Class: ActiveRecord::Reflection::AbstractReflection

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

Overview

Holds all the methods that are shared between MacroReflection and ThroughReflection.

AbstractReflection
MacroReflection
  AggregateReflection
  AssociationReflection
    HasManyReflection
    HasOneReflection
    BelongsToReflection
    HasAndBelongsToManyReflection
ThroughReflection
  PolymorphicReflection
    RuntimeReflection

Direct Known Subclasses

MacroReflection, ThroughReflection

Defined Under Namespace

Classes: JoinKeys

Instance Method Summary collapse

Instance Method Details

#alias_candidate(name) ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 243

def alias_candidate(name)
  "#{plural_name}_#{name}"
end

#build_association(attributes, &block) ⇒ Object

Returns a new, unsaved instance of the associated class. attributes will be passed to the class's constructor.



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# File 'lib/active_record/reflection.rb', line 151

def build_association(attributes, &block)
  klass.new(attributes, &block)
end

#chain ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 247

def chain
  collect_join_chain
end

#check_validity_of_inverse! ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 199

def check_validity_of_inverse!
  unless polymorphic?
    if has_inverse? && inverse_of.nil?
      raise InverseOfAssociationNotFoundError.new(self)
    end
  end
end

#class_name ⇒ Object

Returns the class name for the macro.

composed_of :balance, class_name: 'Money' returns 'Money' has_many :clients returns 'Client'



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# File 'lib/active_record/reflection.rb', line 167

def class_name
  @class_name ||= (options[:class_name] || derive_class_name).to_s
end

#constraints ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 177

def constraints
  scope_chain.flatten
end

#counter_cache_column ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 181

def counter_cache_column
  if belongs_to?
    if options[:counter_cache] == true
      "#{active_record.name.demodulize.underscore.pluralize}_count"
    elsif options[:counter_cache]
      options[:counter_cache].to_s
    end
  else
    options[:counter_cache] ? options[:counter_cache].to_s : "#{name}_count"
  end
end

#counter_must_be_updated_by_has_many? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/reflection.rb', line 239

def counter_must_be_updated_by_has_many?
  !inverse_updates_counter_in_memory? && has_cached_counter?
end

#has_cached_counter? ⇒ Boolean

Returns whether a counter cache should be used for this association.

The counter_cache option must be given on either the owner or inverse association, and the column must be present on the owner.

Returns:

  • (Boolean) 


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# File 'lib/active_record/reflection.rb', line 233

def has_cached_counter?
  options[:counter_cache] ||
    inverse_which_updates_counter_cache && inverse_which_updates_counter_cache.options[:counter_cache] &&
    !!active_record.columns_hash[counter_cache_column]
end

#inverse_of ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 193

def inverse_of
  return unless inverse_name

  @inverse_of ||= klass._reflect_on_association inverse_name
end

#inverse_updates_counter_in_memory? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/reflection.rb', line 225

def inverse_updates_counter_in_memory?
  inverse_of && inverse_which_updates_counter_cache == inverse_of
end

#inverse_which_updates_counter_cache ⇒ Object Also known as: inverse_updates_counter_cache?

This shit is nasty. We need to avoid the following situation:

* An associated record is deleted via record.destroy
* Hence the callbacks run, and they find a belongs_to on the record with a
:counter_cache options which points back at our owner. So they update the
counter cache.
* In which case, we must make sure to *not* update the counter cache, or else
it will be decremented twice.

Hence this method.



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# File 'lib/active_record/reflection.rb', line 217

def inverse_which_updates_counter_cache
  return @inverse_which_updates_counter_cache if defined?(@inverse_which_updates_counter_cache)
  @inverse_which_updates_counter_cache = klass.reflect_on_all_associations(:belongs_to).find do |inverse|
    inverse.counter_cache_column == counter_cache_column
  end
end

#join_keys(association_klass) ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 173

def join_keys(association_klass)
  JoinKeys.new(foreign_key, active_record_primary_key)
end

#primary_key_type ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 159

def primary_key_type
  klass.type_for_attribute(klass.primary_key)
end

#quoted_table_name ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 155

def quoted_table_name
  klass.quoted_table_name
end

#table_name ⇒ Object 



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# File 'lib/active_record/reflection.rb', line 145

def table_name
  klass.table_name
end

#through_reflection? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/active_record/reflection.rb', line 141

def through_reflection?
  false
end