Class: ActiveRecord::Associations::AssociationCollection

Inherits:
AssociationProxy show all
Defined in:
activerecord/lib/active_record/associations/association_collection.rb

Overview

AssociationCollection is an abstract class that provides common stuff to ease the implementation of association proxies that represent collections. See the class hierarchy in AssociationProxy.

You need to be careful with assumptions regarding the target: The proxy does not fetch records from the database until it needs them, but new ones created with build are added to the target. So, the target may be non-empty and still lack children waiting to be read from the database. If you look directly to the database you cannot assume that's the entire collection because new records may have beed added to the target, etc.

If you need to work on all current children, new and existing records, load_target and the loaded flag are your friends.

Direct Known Subclasses

HasAndBelongsToManyAssociation, HasManyAssociation

Instance Method Summary (collapse)

Methods inherited from AssociationProxy

#===, #aliased_table_name, #conditions, #inspect, #loaded, #loaded?, #proxy_owner, #proxy_reflection, #proxy_target, #reload, #respond_to?, #send, #target, #target=

Constructor Details

- (AssociationCollection) initialize(owner, reflection)

:nodoc:



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 19

def initialize(owner, reflection)
  super
  construct_sql
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

- (Object) method_missing(method, *args) (protected)



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 366

def method_missing(method, *args)
  if @target.respond_to?(method) || (!@reflection.klass.respond_to?(method) && Class.respond_to?(method))
    if block_given?
      super { |*block_args| yield(*block_args) }
    else
      super
    end
  elsif @reflection.klass.scopes.include?(method)
    @reflection.klass.scopes[method].call(self, *args)
  else          
    with_scope(construct_scope) do
      if block_given?
        @reflection.klass.send(method, *args) { |*block_args| yield(*block_args) }
      else
        @reflection.klass.send(method, *args)
      end
    end
  end
end

Instance Method Details

- (Object) <<(*records) Also known as: push, concat

Add records to this association. Returns self so method calls may be chained. Since << flattens its argument list and inserts each record, push and concat behave identically.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 111

def <<(*records)
  result = true
  load_target if @owner.new_record?

  transaction do
    flatten_deeper(records).each do |record|
      raise_on_type_mismatch(record)
      add_record_to_target_with_callbacks(record) do |r|
        result &&= insert_record(record) unless @owner.new_record?
      end
    end
  end

  result && self
end

- (Boolean) any?

Returns:

  • (Boolean)


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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 298

def any?
  if block_given?
    method_missing(:any?) { |*block_args| yield(*block_args) }
  else
    !empty?
  end
end

- (Object) build(attributes = {}, &block)



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 98

def build(attributes = {}, &block)
  if attributes.is_a?(Array)
    attributes.collect { |attr| build(attr, &block) }
  else
    build_record(attributes) do |record|
      block.call(record) if block_given?
      set_belongs_to_association_for(record)
    end
  end
end

- (Object) clear

Removes all records from this association. Returns self so method calls may be chained.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 220

def clear
  return self if length.zero? # forces load_target if it hasn't happened already

  if @reflection.options[:dependent] && @reflection.options[:dependent] == :destroy
    destroy_all
  else          
    delete_all
  end

  self
end

- (Object) count(*args)

Count all records using SQL. If the :counter_sql option is set for the association, it will be used for the query. If no :counter_sql was supplied, but :finder_sql was set, the descendant's construct_sql method will have set :counter_sql automatically. Otherwise, construct options and pass them with scope to the target class's count.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 167

def count(*args)
  if @reflection.options[:counter_sql]
    @reflection.klass.count_by_sql(@counter_sql)
  else
    column_name, options = @reflection.klass.send(:construct_count_options_from_args, *args)
    if @reflection.options[:uniq]
      # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL.
      column_name = "#{@reflection.quoted_table_name}.#{@reflection.klass.primary_key}" if column_name == :all
      options.merge!(:distinct => true)
    end

    value = @reflection.klass.send(:with_scope, construct_scope) { @reflection.klass.count(column_name, options) }

    limit  = @reflection.options[:limit]
    offset = @reflection.options[:offset]

    if limit || offset
      [ [value - offset.to_i, 0].max, limit.to_i ].min
    else
      value
    end
  end
end

- (Object) create(attrs = {})



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 241

def create(attrs = {})
  if attrs.is_a?(Array)
    attrs.collect { |attr| create(attr) }
  else
    create_record(attrs) do |record|
      yield(record) if block_given?
      record.save
    end
  end
end

- (Object) create!(attrs = {})



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 252

def create!(attrs = {})
  create_record(attrs) do |record|
    yield(record) if block_given?
    record.save!
  end
end

- (Object) delete(*records)

Removes records from this association calling before_remove and after_remove callbacks.

This method is abstract in the sense that delete_records has to be provided by descendants. Note this method does not imply the records are actually removed from the database, that depends precisely on delete_records. They are in any case removed from the collection.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 198

def delete(*records)
  remove_records(records) do |records, old_records|
    delete_records(old_records) if old_records.any?
    records.each { |record| @target.delete(record) }
  end
end

- (Object) delete_all

Remove all records from this association

See delete for more info.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 148

def delete_all
  load_target
  delete(@target)
  reset_target!
end

- (Object) destroy(*records)

Destroy records and remove them from this association calling before_remove and after_remove callbacks.

Note that this method will always remove records from the database ignoring the :dependent option.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 210

def destroy(*records)
  records = find(records) if records.any? {|record| record.kind_of?(Fixnum) || record.kind_of?(String)}
  remove_records(records) do |records, old_records|
    old_records.each { |record| record.destroy }
  end

  load_target
end

- (Object) destroy_all

Destory all the records from this association.

See destroy for more info.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 235

def destroy_all
  load_target
  destroy(@target)
  reset_target!
end

- (Boolean) empty?

Equivalent to collection.size.zero?. If the collection has not been already loaded and you are going to fetch the records anyway it is better to check collection.length.zero?.

Returns:

  • (Boolean)


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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 294

def empty?
  size.zero?
end

- (Object) find(*args)



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 24

def find(*args)
  options = args.extract_options!

  # If using a custom finder_sql, scan the entire collection.
  if @reflection.options[:finder_sql]
    expects_array = args.first.kind_of?(Array)
    ids           = args.flatten.compact.uniq.map { |arg| arg.to_i }

    if ids.size == 1
      id = ids.first
      record = load_target.detect { |r| id == r.id }
      expects_array ? [ record ] : record
    else
      load_target.select { |r| ids.include?(r.id) }
    end
  else
    conditions = "#{@finder_sql}"
    if sanitized_conditions = sanitize_sql(options[:conditions])
      conditions << " AND (#{sanitized_conditions})"
    end
    
    options[:conditions] = conditions

    if options[:order] && @reflection.options[:order]
      options[:order] = "#{options[:order]}, #{@reflection.options[:order]}"
    elsif @reflection.options[:order]
      options[:order] = @reflection.options[:order]
    end
    
    # Build options specific to association
    construct_find_options!(options)
    
    merge_options_from_reflection!(options)
    
    # Pass through args exactly as we received them.
    args << options
    @reflection.klass.find(*args)
  end
end

- (Object) first(*args)

Fetches the first one using SQL if possible.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 65

def first(*args)
  if fetch_first_or_last_using_find?(args)
    find(:first, *args)
  else
    load_target unless loaded?
    @target.first(*args)
  end
end

- (Boolean) include?(record)

Returns:

  • (Boolean)


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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 332

def include?(record)
  return false unless record.is_a?(@reflection.klass)
  load_target if @reflection.options[:finder_sql] && !loaded?
  return @target.include?(record) if loaded?
  exists?(record)
end

- (Object) last(*args)

Fetches the last one using SQL if possible.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 75

def last(*args)
  if fetch_first_or_last_using_find?(args)
    find(:last, *args)
  else
    load_target unless loaded?
    @target.last(*args)
  end
end

- (Object) length

Returns the size of the collection calling size on the target.

If the collection has been already loaded length and size are equivalent. If not and you are going to need the records anyway this method will take one less query. Otherwise size is more efficient.



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

def length
  load_target.size
end

- (Boolean) proxy_respond_to?(method, include_private = false)

Returns:

  • (Boolean)


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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 339

def proxy_respond_to?(method, include_private = false)
  super || @reflection.klass.respond_to?(method, include_private)
end

- (Object) replace(other_array)

Replace this collection with other_array This will perform a diff and delete/add only records that have changed.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 319

def replace(other_array)
  other_array.each { |val| raise_on_type_mismatch(val) }

  load_target
  other   = other_array.size < 100 ? other_array : other_array.to_set
  current = @target.size < 100 ? @target : @target.to_set

  transaction do
    delete(@target.select { |v| !other.include?(v) })
    concat(other_array.select { |v| !current.include?(v) })
  end
end

- (Object) reset



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 93

def reset
  reset_target!
  @loaded = false
end

- (Object) size

Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn't been loaded, and calling collection.size if it has.

If the collection has been already loaded size and length are equivalent. If not and you are going to need the records anyway length will take one less query. Otherwise size is more efficient.

This method is abstract in the sense that it relies on count_records, which is a method descendants have to provide.



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 269

def size
  if @owner.new_record? || (loaded? && !@reflection.options[:uniq])
    @target.size
  elsif !loaded? && @reflection.options[:group]
    load_target.size
  elsif !loaded? && !@reflection.options[:uniq] && @target.is_a?(Array)
    unsaved_records = @target.select { |r| r.new_record? }
    unsaved_records.size + count_records
  else
    count_records
  end
end

- (Object) sum(*args)

Calculate sum using SQL, not Enumerable



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 155

def sum(*args)
  if block_given?
    calculate(:sum, *args) { |*block_args| yield(*block_args) }
  else
    calculate(:sum, *args)
  end
end

- (Object) to_ary



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 84

def to_ary
  load_target
  if @target.is_a?(Array)
    @target.to_ary
  else
    Array(@target)
  end
end

- (Object) transaction(*args)

Starts a transaction in the association class's database connection.

class Author < ActiveRecord::Base
  has_many :books
end

Author.find(:first).books.transaction do
  # same effect as calling Book.transaction
end


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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 139

def transaction(*args)
  @reflection.klass.transaction(*args) do
    yield
  end
end

- (Object) uniq(collection = self)



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# File 'activerecord/lib/active_record/associations/association_collection.rb', line 306

def uniq(collection = self)
  seen = Set.new
  collection.inject([]) do |kept, record|
    unless seen.include?(record.id)
      kept << record
      seen << record.id
    end
    kept
  end
end