module ActiveRecord::Core
Public Class Methods
Returns fully resolved configurations hash
# File activerecord/lib/active_record/core.rb, line 52 def self.configurations @@configurations end
Contains the database configuration - as is typically stored in config/database.yml - as a Hash
.
For example, the following database.yml…
development: adapter: sqlite3 database: db/development.sqlite3 production: adapter: sqlite3 database: db/production.sqlite3
…would result in ActiveRecord::Base.configurations
to look like this:
{ 'development' => { 'adapter' => 'sqlite3', 'database' => 'db/development.sqlite3' }, 'production' => { 'adapter' => 'sqlite3', 'database' => 'db/production.sqlite3' } }
# File activerecord/lib/active_record/core.rb, line 46 def self.configurations=(config) @@configurations = ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve end
# File activerecord/lib/active_record/core.rb, line 135 def self.connection_handler ActiveRecord::RuntimeRegistry.connection_handler || default_connection_handler end
# File activerecord/lib/active_record/core.rb, line 139 def self.connection_handler=(handler) ActiveRecord::RuntimeRegistry.connection_handler = handler end
# File activerecord/lib/active_record/core.rb, line 79 def self.error_on_ignored_order_or_limit ActiveSupport::Deprecation.warn(<<-MSG.squish) The flag error_on_ignored_order_or_limit is deprecated. Limits are now supported. Please use error_on_ignored_order instead. MSG error_on_ignored_order end
# File activerecord/lib/active_record/core.rb, line 91 def self.error_on_ignored_order_or_limit=(value) ActiveSupport::Deprecation.warn(<<-MSG.squish) The flag error_on_ignored_order_or_limit is deprecated. Limits are now supported. Please use error_on_ignored_order= instead. MSG self.error_on_ignored_order = value end
New objects can be instantiated as either empty (pass no construction parameter) or pre-set with attributes but not yet saved (pass a hash with key names matching the associated table column names). In both instances, valid attribute keys are determined by the column names of the associated table – hence you can't have attributes that aren't part of the table columns.
Example:¶ ↑
# Instantiates a single new object User.new(first_name: 'Jamie')
# File activerecord/lib/active_record/core.rb, line 311 def initialize(attributes = nil) self.class.define_attribute_methods @attributes = self.class._default_attributes.deep_dup init_internals initialize_internals_callback assign_attributes(attributes) if attributes yield self if block_given? _run_initialize_callbacks end
Public Instance Methods
Allows sort on objects
# File activerecord/lib/active_record/core.rb, line 454 def <=>(other_object) if other_object.is_a?(self.class) to_key <=> other_object.to_key else super end end
Returns true if comparison_object
is the same exact object, or comparison_object
is of the same type and self
has an ID and it is equal to comparison_object.id
.
Note that new records are different from any other record by definition, unless the other record is the receiver itself. Besides, if you fetch existing records with select
and leave the ID out, you're on your own, this predicate will return false.
Note also that destroying a record preserves its ID in the model instance, so deleted models are still comparable.
# File activerecord/lib/active_record/core.rb, line 422 def ==(comparison_object) super || comparison_object.instance_of?(self.class) && !id.nil? && comparison_object.id == id end
Identical to Ruby's clone method. This is a “shallow” copy. Be warned that your attributes are not copied. That means that modifying attributes of the clone will modify the original, since they will both point to the same attributes hash. If you need a copy of your attributes hash, please use the dup
method.
user = User.first new_user = user.clone user.name # => "Bob" new_user.name = "Joe" user.name # => "Joe" user.object_id == new_user.object_id # => false user.name.object_id == new_user.name.object_id # => true user.name.object_id == user.dup.name.object_id # => false
# File activerecord/lib/active_record/core.rb, line 357
# File activerecord/lib/active_record/core.rb, line 473 def connection_handler self.class.connection_handler end
Duped objects have no id assigned and are treated as new records. Note that this is a “shallow” copy as it copies the object's attributes only, not its associations. The extent of a “deep” copy is application specific and is therefore left to the application to implement according to its need. The dup method does not preserve the timestamps (created|updated)_(at|on).
# File activerecord/lib/active_record/core.rb, line 374
Populate coder
with attributes about this record that should be serialized. The structure of coder
defined in this method is guaranteed to match the structure of coder
passed to the init_with
method.
Example:
class Post < ActiveRecord::Base end coder = {} Post.new.encode_with(coder) coder # => {"attributes" => {"id" => nil, ... }}
# File activerecord/lib/active_record/core.rb, line 407 def encode_with(coder) self.class.yaml_encoder.encode(@attributes, coder) coder["new_record"] = new_record? coder["active_record_yaml_version"] = 2 end
# File activerecord/lib/active_record/core.rb, line 87 def error_on_ignored_order_or_limit self.class.error_on_ignored_order_or_limit end
Clone and freeze the attributes hash such that associations are still accessible, even on destroyed records, but cloned models will not be frozen.
# File activerecord/lib/active_record/core.rb, line 443 def freeze @attributes = @attributes.clone.freeze self end
Returns true
if the attributes hash has been frozen.
# File activerecord/lib/active_record/core.rb, line 449 def frozen? @attributes.frozen? end
Delegates to id in order to allow two records of the same type and id to work with something like:
[ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
# File activerecord/lib/active_record/core.rb, line 432 def hash if id self.class.hash ^ id.hash else super end end
Initialize an empty model object from coder
. coder
should be the result of previously encoding an Active Record
model, using encode_with
.
class Post < ActiveRecord::Base end old_post = Post.new(title: "hello world") coder = {} old_post.encode_with(coder) post = Post.allocate post.init_with(coder) post.title # => 'hello world'
# File activerecord/lib/active_record/core.rb, line 338 def init_with(coder) coder = LegacyYamlAdapter.convert(self.class, coder) @attributes = self.class.yaml_encoder.decode(coder) init_internals @new_record = coder["new_record"] self.class.define_attribute_methods yield self if block_given? _run_find_callbacks _run_initialize_callbacks self end
Returns the contents of the record as a nicely formatted string.
# File activerecord/lib/active_record/core.rb, line 478 def inspect # We check defined?(@attributes) not to issue warnings if the object is # allocated but not initialized. inspection = if defined?(@attributes) && @attributes self.class.attribute_names.collect do |name| if has_attribute?(name) "#{name}: #{attribute_for_inspect(name)}" end end.compact.join(", ") else "not initialized" end "#<#{self.class} #{inspection}>" end
Takes a PP and prettily prints this record to it, allowing you to get a nice result from pp record
when pp is required.
# File activerecord/lib/active_record/core.rb, line 496 def pretty_print(pp) return super if custom_inspect_method_defined? pp.object_address_group(self) do if defined?(@attributes) && @attributes column_names = self.class.column_names.select { |name| has_attribute?(name) || new_record? } pp.seplist(column_names, proc { pp.text "," }) do |column_name| column_value = read_attribute(column_name) pp.breakable " " pp.group(1) do pp.text column_name pp.text ":" pp.breakable pp.pp column_value end end else pp.breakable " " pp.text "not initialized" end end end
Marks this record as read only.
# File activerecord/lib/active_record/core.rb, line 469 def readonly! @readonly = true end
Returns true
if the record is read only. Records loaded through joins with piggy-back attributes will be marked as read only since they cannot be saved.
# File activerecord/lib/active_record/core.rb, line 464 def readonly? @readonly end
Returns a hash of the given methods with their names as keys and returned values as values.
# File activerecord/lib/active_record/core.rb, line 519 def slice(*methods) Hash[methods.flatten.map! { |method| [method, public_send(method)] }].with_indifferent_access end
Private Instance Methods
# File activerecord/lib/active_record/core.rb, line 556 def custom_inspect_method_defined? self.class.instance_method(:inspect).owner != ActiveRecord::Base.instance_method(:inspect).owner end
# File activerecord/lib/active_record/core.rb, line 537 def init_internals @readonly = false @destroyed = false @marked_for_destruction = false @destroyed_by_association = nil @new_record = true @_start_transaction_state = {} @transaction_state = nil end
# File activerecord/lib/active_record/core.rb, line 547 def initialize_internals_callback end
# File activerecord/lib/active_record/core.rb, line 550 def thaw if frozen? @attributes = @attributes.dup end end
+Array#flatten+ will call #to_ary
(recursively) on each of the elements of the array, and then rescues from the possible NoMethodError
. If those elements are ActiveRecord::Base
's, then this triggers the various method_missing
's that we have, which significantly impacts upon performance.
So we can avoid the method_missing
hit by explicitly defining #to_ary
as nil
here.
See also tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary.html
# File activerecord/lib/active_record/core.rb, line 533 def to_ary nil end