Class: ActiveRecord::Associations::JoinDependency::JoinAssociation

Inherits:
JoinPart
  • Object
show all
Includes:
ActiveRecord::Associations::JoinHelper
Defined in:
activerecord/lib/active_record/associations/join_dependency/join_association.rb

Overview

:nodoc:

Instance Attribute Summary collapse

Attributes inherited from JoinPart

#active_record

Instance Method Summary collapse

Methods inherited from JoinPart

#aliased_primary_key, #aliased_table, #column_names_with_alias, #extract_record, #instantiate, #record_id

Constructor Details

#initialize(reflection, join_dependency, parent = nil) ⇒ JoinAssociation

Returns a new instance of JoinAssociation.



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 33

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

Instance Attribute Details

#aliased_prefix ⇒ Object (readonly)

These implement abstract methods from the superclass



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 23

def aliased_prefix
  @aliased_prefix
end

#join_dependency ⇒ Object (readonly)

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.



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 13

def join_dependency
  @join_dependency
end

#join_type ⇒ Object

What type of join will be generated, either Arel::InnerJoin (default) or Arel::OuterJoin



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 20

def join_type
  @join_type
end

#parent ⇒ Object (readonly)

A JoinBase instance representing the active record we are joining onto. (So in Author.has_many :posts, the Author would be that base record.)



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 17

def parent
  @parent
end

#reflection ⇒ Object (readonly)

The reflection of the association represented



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 8

def reflection
  @reflection
end

#tables ⇒ Object (readonly)

Returns the value of attribute tables



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 25

def tables
  @tables
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 50

def ==(other)
  other.class == self.class &&
    other.reflection == reflection &&
    other.parent == parent
end

#aliased_table_name ⇒ Object 



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 133

def aliased_table_name
  table.table_alias || table.name
end

#build_constraint(reflection, table, key, foreign_table, foreign_key) ⇒ Object 



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

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

#conditions ⇒ Object 



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 137

def conditions
  @conditions ||= reflection.conditions.reverse
end

#find_parent_in(other_join_dependency) ⇒ Object 



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 56

def find_parent_in(other_join_dependency)
  other_join_dependency.join_parts.detect do |join_part|
    parent == join_part
  end
end

#join_relation(joining_relation) ⇒ Object 



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 124

def join_relation(joining_relation)
  self.join_type = Arel::OuterJoin
  joining_relation.joins(self)
end

#join_to(relation) ⇒ Object 



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 62

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

#table ⇒ Object 



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# File 'activerecord/lib/active_record/associations/join_dependency/join_association.rb', line 129

def table
  tables.last
end