Class: ActiveRecord::Associations::HasAndBelongsToManyAssociation

Inherits:
AssociationCollection show all
Defined in:
lib/active_record/associations/has_and_belongs_to_many_association.rb

Overview

:nodoc:

Instance Method Summary collapse

Methods inherited from AssociationCollection

#<<, #create, #delete, #destroy_all, #empty?, #length, #replace, #reset, #to_ary, #uniq

Methods inherited from AssociationProxy

#loaded, #loaded?, #method_missing, #proxy_respond_to?, #reload, #respond_to?, #target, #target=

Constructor Details

#initialize(owner, association_name, association_class_name, association_class_primary_key_name, options) ⇒ HasAndBelongsToManyAssociation

Returns a new instance of HasAndBelongsToManyAssociation.



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# File 'lib/active_record/associations/has_and_belongs_to_many_association.rb', line 4

def initialize(owner, association_name, association_class_name, association_class_primary_key_name, options)
  super

  @association_foreign_key = options[:association_foreign_key] || Inflector.underscore(Inflector.demodulize(association_class_name)) + "_id"
  @association_table_name = options[:table_name] || @association_class.table_name
  @join_table = options[:join_table]
  @order = options[:order]

  construct_sql
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class ActiveRecord::Associations::AssociationProxy

Instance Method Details

#build(attributes = {}) ⇒ Object 



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# File 'lib/active_record/associations/has_and_belongs_to_many_association.rb', line 15

def build(attributes = {})
  load_target
  record = @association_class.new(attributes)
  @target << record
  record
end

#clear ⇒ Object

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



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# File 'lib/active_record/associations/has_and_belongs_to_many_association.rb', line 23

def clear
  return self if size == 0 # forces load_target if hasn't happened already

  if sql = @options[:delete_sql]
    each { |record| @owner.connection.execute(sql) }
  elsif @options[:conditions] 
    sql = 
      "DELETE FROM #{@join_table} WHERE #{@association_class_primary_key_name} = #{@owner.quoted_id} " +
      "AND #{@association_foreign_key} IN (#{collect { |record| record.id }.join(", ")})"
    @owner.connection.execute(sql)
  else
    sql = "DELETE FROM #{@join_table} WHERE #{@association_class_primary_key_name} = #{@owner.quoted_id}"
    @owner.connection.execute(sql)
  end

  @target = []
  self
end

#find(*args) ⇒ Object 



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# File 'lib/active_record/associations/has_and_belongs_to_many_association.rb', line 46

def find(*args)
  # Return an Array if multiple ids are given.
  expects_array = args.first.kind_of?(Array)

  ids = args.flatten.compact.uniq

  # If no block is given, raise RecordNotFound.
  if ids.empty?
    raise RecordNotFound, "Couldn't find #{@association_class.name} without an ID"

  # If using a custom finder_sql, scan the entire collection.
  elsif @options[:finder_sql]
    if ids.size == 1
      id = ids.first
      record = load_target.detect { |record| id == record.id }
      expects_array? ? [record] : record
    else
      load_target.select { |record| ids.include?(record.id) }
    end

  # Otherwise, construct a query.
  else
    ids_list = ids.map { |id| @owner.send(:quote, id) }.join(',')
    records = find_target(@finder_sql.sub(/(ORDER BY|$)/, " AND j.#{@association_foreign_key} IN (#{ids_list}) \\1"))
    if records.size == ids.size
      if ids.size == 1 and !expects_array
        records.first
      else
        records
      end
    else
      raise RecordNotFound, "Couldn't find #{@association_class.name} with ID in (#{ids_list})"
    end
  end
end

#find_first ⇒ Object 



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# File 'lib/active_record/associations/has_and_belongs_to_many_association.rb', line 42

def find_first
  load_target.first
end

#push_with_attributes(record, join_attributes = {}) ⇒ Object Also known as: concat_with_attributes 



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# File 'lib/active_record/associations/has_and_belongs_to_many_association.rb', line 82

def push_with_attributes(record, join_attributes = {})
  raise_on_type_mismatch(record)
  join_attributes.each { |key, value| record[key.to_s] = value }
  callback(:before_add, record)
  insert_record(record) unless @owner.new_record?
  @target << record
  callback(:after_add, record)
  self
end

#size ⇒ Object 



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# File 'lib/active_record/associations/has_and_belongs_to_many_association.rb', line 94

def size
  @options[:uniq] ? count_records : super
end