Class: ActiveRecord::Reflection::AbstractReflection

Inherits:
Object
  • Object
show all
Defined in:
activerecord/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

Defined Under Namespace

Classes: JoinKeys

Instance Method Summary collapse

Instance Method Details

#alias_candidate(name) ⇒ Object


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# File 'activerecord/lib/active_record/reflection.rb', line 283

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 'activerecord/lib/active_record/reflection.rb', line 157

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

#build_scope(table, predicate_builder = predicate_builder(table)) ⇒ Object


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# File 'activerecord/lib/active_record/reflection.rb', line 295

def build_scope(table, predicate_builder = predicate_builder(table))
  Relation.create(
    klass,
    table: table,
    predicate_builder: predicate_builder
  )
end

#chainObject


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# File 'activerecord/lib/active_record/reflection.rb', line 287

def chain
  collect_join_chain
end

#check_validity_of_inverse!Object


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

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

#class_nameObject

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 'activerecord/lib/active_record/reflection.rb', line 165

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

#constraintsObject


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

def constraints
  chain.flat_map(&:scopes)
end

#counter_cache_columnObject


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# File 'activerecord/lib/active_record/reflection.rb', line 221

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 'activerecord/lib/active_record/reflection.rb', line 279

def counter_must_be_updated_by_has_many?
  !inverse_updates_counter_in_memory? && has_cached_counter?
end

#get_join_keys(association_klass) ⇒ Object


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# File 'activerecord/lib/active_record/reflection.rb', line 291

def get_join_keys(association_klass)
  JoinKeys.new(join_primary_key(association_klass), join_foreign_key)
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 'activerecord/lib/active_record/reflection.rb', line 273

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_ofObject


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

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 'activerecord/lib/active_record/reflection.rb', line 265

def inverse_updates_counter_in_memory?
  inverse_of && inverse_which_updates_counter_cache == inverse_of
end

#inverse_which_updates_counter_cacheObject 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 'activerecord/lib/active_record/reflection.rb', line 257

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_foreign_keyObject


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# File 'activerecord/lib/active_record/reflection.rb', line 307

def join_foreign_key
  active_record_primary_key
end

#join_keysObject


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# File 'activerecord/lib/active_record/reflection.rb', line 171

def join_keys
  @join_keys ||= get_join_keys(klass)
end

#join_primary_keyObject


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# File 'activerecord/lib/active_record/reflection.rb', line 303

def join_primary_key(*)
  foreign_key
end

#join_scope(table, foreign_table, foreign_klass) ⇒ Object


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

def join_scope(table, foreign_table, foreign_klass)
  predicate_builder = predicate_builder(table)
  scope_chain_items = join_scopes(table, predicate_builder)
  klass_scope       = klass_join_scope(table, predicate_builder)

  if type
    klass_scope.where!(type => foreign_klass.polymorphic_name)
  end

  scope_chain_items.inject(klass_scope, &:merge!)

  key         = join_keys.key
  foreign_key = join_keys.foreign_key

  klass_scope.where!(table[key].eq(foreign_table[foreign_key]))

  if klass.finder_needs_type_condition?
    klass_scope.where!(klass.send(:type_condition, table))
  end

  klass_scope
end

#join_scopes(table, predicate_builder) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/reflection.rb', line 204

def join_scopes(table, predicate_builder) # :nodoc:
  if scope
    [scope_for(build_scope(table, predicate_builder))]
  else
    []
  end
end

#klass_join_scope(table, predicate_builder) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/reflection.rb', line 212

def klass_join_scope(table, predicate_builder) # :nodoc:
  relation = build_scope(table, predicate_builder)
  klass.scope_for_association(relation)
end

#scopesObject

Returns a list of scopes that should be applied for this Reflection object when querying the database.


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

def scopes
  scope ? [scope] : []
end

#strict_loading?Boolean

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/reflection.rb', line 311

def strict_loading?
  options[:strict_loading]
end

#table_nameObject


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

def table_name
  klass.table_name
end

#through_reflection?Boolean

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/reflection.rb', line 147

def through_reflection?
  false
end