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tag: v3.1.4
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module ActiveRecord
module Associations
class JoinDependency # :nodoc:
class JoinAssociation < JoinPart # :nodoc:
include JoinHelper
# The reflection of the association represented
attr_reader :reflection
# The JoinDependency object which this JoinAssociation exists within. This is mainly
# relevant for generating aliases which do not conflict with other joins which are
# part of the query.
attr_reader :join_dependency
# A JoinBase instance representing the active record we are joining onto.
# (So in Author.has_many :posts, the Author would be that base record.)
attr_reader :parent
# What type of join will be generated, either Arel::InnerJoin (default) or Arel::OuterJoin
attr_accessor :join_type
# These implement abstract methods from the superclass
attr_reader :aliased_prefix
attr_reader :tables
delegate :options, :through_reflection, :source_reflection, :chain, :to => :reflection
delegate :table, :table_name, :to => :parent, :prefix => :parent
delegate :alias_tracker, :to => :join_dependency
alias :alias_suffix :parent_table_name
def initialize(reflection, join_dependency, parent = nil)
reflection.check_validity!
if reflection.options[:polymorphic]
raise EagerLoadPolymorphicError.new(reflection)
end
super(reflection.klass)
@reflection = reflection
@join_dependency = join_dependency
@parent = parent
@join_type = Arel::InnerJoin
@aliased_prefix = "t#{ join_dependency.join_parts.size }"
@tables = construct_tables.reverse
end
def ==(other)
other.class == self.class &&
other.reflection == reflection &&
other.parent == parent
end
def find_parent_in(other_join_dependency)
other_join_dependency.join_parts.detect do |join_part|
parent == join_part
end
end
def join_to(relation)
tables = @tables.dup
foreign_table = parent_table
foreign_klass = parent.active_record
# The chain starts with the target table, but we want to end with it here (makes
# more sense in this context), so we reverse
chain.reverse.each_with_index do |reflection, i|
table = tables.shift
case reflection.source_macro
when :belongs_to
key = reflection.association_primary_key
foreign_key = reflection.foreign_key
when :has_and_belongs_to_many
# Join the join table first...
relation.from(join(
table,
table[reflection.foreign_key].
eq(foreign_table[reflection.active_record_primary_key])
))
foreign_table, table = table, tables.shift
key = reflection.association_primary_key
foreign_key = reflection.association_foreign_key
else
key = reflection.foreign_key
foreign_key = reflection.active_record_primary_key
end
constraint = build_constraint(reflection, table, key, foreign_table, foreign_key)
conditions = self.conditions[i].dup
conditions << { reflection.type => foreign_klass.base_class.name } if reflection.type
unless conditions.empty?
constraint = constraint.and(sanitize(conditions, table))
end
relation.from(join(table, constraint))
# The current table in this iteration becomes the foreign table in the next
foreign_table, foreign_klass = table, reflection.klass
end
relation
end
def build_constraint(reflection, table, key, foreign_table, foreign_key)
constraint = table[key].eq(foreign_table[foreign_key])
if reflection.klass.finder_needs_type_condition?
constraint = table.create_and([
constraint,
reflection.klass.send(:type_condition, table)
])
end
constraint
end
def join_relation(joining_relation)
self.join_type = Arel::OuterJoin
joining_relation.joins(self)
end
def table
tables.last
end
def aliased_table_name
table.table_alias || table.name
end
def conditions
@conditions ||= reflection.conditions.reverse
end
private
def interpolate(conditions)
if conditions.respond_to?(:to_proc)
instance_eval(&conditions)
else
conditions
end
end
end
end
end
end
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