module ActiveRecord::Persistence::ClassMethods
Public Instance Methods
Creates an object (or multiple objects) and saves it to the database, if validations pass. The resulting object is returned whether the object was saved successfully to the database or not.
The attributes
parameter can be either a Hash
or an Array
of Hashes. These Hashes describe the attributes on the objects that are to be created.
Examples¶ ↑
# Create a single new object User.create(first_name: 'Jamie') # Create an Array of new objects User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }]) # Create a single object and pass it into a block to set other attributes. User.create(first_name: 'Jamie') do |u| u.is_admin = false end # Creating an Array of new objects using a block, where the block is executed for each object: User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }]) do |u| u.is_admin = false end
# File activerecord/lib/active_record/persistence.rb, line 31 def create(attributes = nil, &block) if attributes.is_a?(Array) attributes.collect { |attr| create(attr, &block) } else object = new(attributes, &block) object.save object end end
Creates an object (or multiple objects) and saves it to the database, if validations pass. Raises a RecordInvalid
error if validations fail, unlike Base#create.
The attributes
parameter can be either a Hash
or an Array
of Hashes. These describe which attributes to be created on the object, or multiple objects when given an Array
of Hashes.
# File activerecord/lib/active_record/persistence.rb, line 48 def create!(attributes = nil, &block) if attributes.is_a?(Array) attributes.collect { |attr| create!(attr, &block) } else object = new(attributes, &block) object.save! object end end
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.
# 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
Private Instance Methods
Called by instantiate
to decide which class to use for a new record instance.
See +ActiveRecord::Inheritance#discriminate_class_for_record+ for the single-table inheritance discriminator.
# File activerecord/lib/active_record/persistence.rb, line 80 def discriminate_class_for_record(record) self end