- MODULE ActiveRecord::Core::ClassMethods
- MODULE ActiveRecord::Core::YAML
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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 170 def initialize(attributes = nil, options = {}) defaults = self.class.column_defaults.dup defaults.each { |k, v| defaults[k] = v.dup if v.duplicable? } @attributes = self.class.initialize_attributes(defaults) @column_types_override = nil @column_types = self.class.column_types init_internals init_changed_attributes ensure_proper_type populate_with_current_scope_attributes # +options+ argument is only needed to make protected_attributes gem easier to hook. # Remove it when we drop support to this gem. init_attributes(attributes, options) if attributes yield self if block_given? run_callbacks :initialize unless _initialize_callbacks.empty? end
Allows sort on objects
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.
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
Returns the connection currently associated with the class. This can also be used to “borrow” the connection to do database work that isn't easily done without going straight to SQL.
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).
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, ... }}
Clone and freeze the attributes hash such that associations are still accessible, even on destroyed records, but cloned models will not be frozen.
Returns true if the attributes hash has been frozen.
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) ]
Initialize an empty model object from coder.
coder must contain the attributes necessary for initializing
an empty model object. For example:
class Post < ActiveRecord::Base
end
post = Post.allocate
post.init_with('attributes' => { 'title' => 'hello world' })
post.title # => 'hello world'
# File activerecord/lib/active_record/core.rb, line 201 def init_with(coder) @attributes = self.class.initialize_attributes(coder['attributes']) @column_types_override = coder['column_types'] @column_types = self.class.column_types init_internals @new_record = false run_callbacks :find run_callbacks :initialize self end
Returns the contents of the record as a nicely formatted string.
# File activerecord/lib/active_record/core.rb, line 349 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.column_names.collect { |name| if has_attribute?(name) "#{name}: #{attribute_for_inspect(name)}" end }.compact.join(", ") else "not initialized" end "#<#{self.class} #{inspection}>" end
Marks this record as read only.
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.
Returns a hash of the given methods with their names as keys and returned values as values.