Class: ActiveRecord::Associations::JoinDependency

Inherits:
Object
  • Object
show all
Defined in:
lib/active_record/associations/join_dependency.rb,
lib/active_record/associations/join_dependency/join_base.rb,
lib/active_record/associations/join_dependency/join_part.rb,
lib/active_record/associations/join_dependency/join_association.rb more...

Overview

:nodoc:

Defined Under Namespace

Classes: Aliases, JoinAssociation, JoinBase, JoinPart

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(base, table, associations, join_type) ⇒ JoinDependency

Returns a new instance of JoinDependency.

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# File 'lib/active_record/associations/join_dependency.rb', line 67

def initialize(base, table, associations, join_type)
  tree = self.class.make_tree associations
  @join_root = JoinBase.new(base, table, build(tree, base))
  @join_type = join_type
end

Class Method Details

.make_tree(associations) ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 43

def self.make_tree(associations)
  hash = {}
  walk_tree associations, hash
  hash
end

.walk_tree(associations, hash) ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 49

def self.walk_tree(associations, hash)
  case associations
  when Symbol, String
    hash[associations.to_sym] ||= {}
  when Array
    associations.each do |assoc|
      walk_tree assoc, hash
    end
  when Hash
    associations.each do |k, v|
      cache = hash[k] ||= {}
      walk_tree v, cache
    end
  else
    raise ConfigurationError, associations.inspect
  end
end

Instance Method Details

#apply_column_aliases(relation) ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 149

def apply_column_aliases(relation)
  @join_root_alias = relation.select_values.empty?
  relation._select!(-> { aliases.columns })
end

#base_klass ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 73

def base_klass
  join_root.base_klass
end

#each(&block) ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 154

def each(&block)
  join_root.each(&block)
end

#instantiate(result_set, strict_loading_value, &block) ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 101

def instantiate(result_set, strict_loading_value, &block)
  primary_key = aliases.column_alias(join_root, join_root.primary_key)

  seen = Hash.new { |i, parent|
    i[parent] = Hash.new { |j, child_class|
      j[child_class] = {}
    }
  }.compare_by_identity

  model_cache = Hash.new { |h, klass| h[klass] = {} }
  parents = model_cache[join_root]

  column_aliases = aliases.column_aliases(join_root)
  column_names = []

  result_set.columns.each do |name|
    column_names << name unless /\At\d+_r\d+\z/.match?(name)
  end

  if column_names.empty?
    column_types = {}
  else
    column_types = result_set.column_types
    unless column_types.empty?
      attribute_types = join_root.attribute_types
      column_types = column_types.slice(*column_names).delete_if { |k, _| attribute_types.key?(k) }
    end
    column_aliases += column_names.map! { |name| Aliases::Column.new(name, name) }
  end

  message_bus = ActiveSupport::Notifications.instrumenter

  payload = {
    record_count: result_set.length,
    class_name: join_root.base_klass.name
  }

  message_bus.instrument("instantiation.active_record", payload) do
    result_set.each { |row_hash|
      parent_key = primary_key ? row_hash[primary_key] : row_hash
      parent = parents[parent_key] ||= join_root.instantiate(row_hash, column_aliases, column_types, &block)
      construct(parent, join_root, row_hash, seen, model_cache, strict_loading_value)
    }
  end

  parents.values
end

#join_constraints(joins_to_add, alias_tracker, references) ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 81

def join_constraints(joins_to_add, alias_tracker, references)
  @alias_tracker = alias_tracker
  @joined_tables = {}
  @references = {}

  references.each do |table_name|
    @references[table_name.to_sym] = table_name if table_name.is_a?(Arel::Nodes::SqlLiteral)
  end unless references.empty?

  joins = make_join_constraints(join_root, join_type)

  joins.concat joins_to_add.flat_map { |oj|
    if join_root.match? oj.join_root
      walk(join_root, oj.join_root, oj.join_type)
    else
      make_join_constraints(oj.join_root, oj.join_type)
    end
  }
end

#reflections ⇒ Object

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# File 'lib/active_record/associations/join_dependency.rb', line 77

def reflections
  join_root.drop(1).map!(&:reflection)
end