instance method `instantiate`

Ruby on Rails 5.2.8.1

Since v4.0.13

Available in: v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

instantiate(attributes, column_types = {}, &block)

Given an attributes hash, instantiate returns a new instance of the appropriate class. Accepts only keys as strings.

For example, Post.all may return Comments, Messages, and Emails by storing the record’s subclass in a type attribute. By calling instantiate instead of new, finder methods ensure they get new instances of the appropriate class for each record.

See ActiveRecord::Inheritance#discriminate_class_for_record to see how this “single-table” inheritance mapping is implemented.

Parameters

attributes req
column_types opt = {}
block block

Source

# File activerecord/lib/active_record/persistence.rb, line 68
      def instantiate(attributes, column_types = {}, &block)
        klass = discriminate_class_for_record(attributes)
        attributes = klass.attributes_builder.build_from_database(attributes, column_types)
        klass.allocate.init_with("attributes" => attributes, "new_record" => false, &block)
      end

Defined in activerecord/lib/active_record/persistence.rb line 68 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::Persistence::ClassMethods

Signature

Parameters