module ActiveRecord
# = Active Record Has And Belongs To Many Association
module Associations
class HasAndBelongsToManyAssociation < AssociationCollection #:nodoc:
attr_reader :join_table
def initialize(owner, reflection)
@join_table_name = reflection.options[:join_table]
@join_table = Arel::Table.new(@join_table_name)
super
end
def columns
@reflection.columns(@join_table_name, "#{@join_table_name} Columns")
end
def reset_column_information
@reflection.reset_column_information
end
def has_primary_key?
@has_primary_key ||= @owner.connection.supports_primary_key? && @owner.connection.primary_key(@join_table_name)
end
protected
def count_records
load_target.size
end
def insert_record(record, force = true, validate = true)
if record.new_record?
return false unless save_record(record, force, validate)
end
if @reflection.options[:insert_sql]
@owner.connection.insert(interpolate_sql(@reflection.options[:insert_sql], record))
else
relation = join_table
timestamps = record_timestamp_columns(record)
timezone = record.send(:current_time_from_proper_timezone) if timestamps.any?
attributes = columns.map do |column|
name = column.name
value = case name.to_s
when @reflection.foreign_key.to_s
@owner.id
when @reflection.association_foreign_key.to_s
record.id
when *timestamps
timezone
else
@owner.send(:quote_value, record[name], column) if record.has_attribute?(name)
end
[relation[name], value] unless value.nil?
end
stmt = relation.compile_insert Hash[attributes]
@owner.connection.insert stmt.to_sql
end
true
end
def delete_records(records)
if sql = @reflection.options[:delete_sql]
records.each { |record| @owner.connection.delete(interpolate_sql(sql, record)) }
else
relation = join_table
stmt = relation.where(relation[@reflection.foreign_key].eq(@owner.id).
and(relation[@reflection.association_foreign_key].in(records.map { |x| x.id }.compact))
).compile_delete
@owner.connection.delete stmt.to_sql
end
end
def construct_joins
right = join_table
left = @reflection.klass.arel_table
condition = left[@reflection.klass.primary_key].eq(
right[@reflection.association_foreign_key])
right.create_join(right, right.create_on(condition))
end
def construct_owner_conditions
super(join_table)
end
def finder_options
super.merge(
:joins => construct_joins,
:readonly => ambiguous_select?(@reflection.options[:select]),
:select => @reflection.options[:select] || [
@reflection.klass.arel_table[Arel.star],
join_table[Arel.star]]
)
end
# Join tables with additional columns on top of the two foreign keys must be considered
# ambiguous unless a select clause has been explicitly defined. Otherwise you can get
# broken records back, if, for example, the join column also has an id column. This will
# then overwrite the id column of the records coming back.
def ambiguous_select?(select)
extra_join_columns? && select.nil?
end
def extra_join_columns?
columns.size > 2
end
private
def record_timestamp_columns(record)
if record.record_timestamps
record.send(:all_timestamp_attributes).map { |x| x.to_s }
else
[]
end
end
def invertible_for?(record)
false
end
def find_by_sql(*args)
options = args.extract_options!
ambiguous = ambiguous_select?(@reflection.options[:select] || options[:select])
scoped.readonly(ambiguous).find(*(args << options))
end
end
end
end