Class: ActiveRecord::Associations::CollectionAssociation
- Inherits:
-
Association
- Object
- Association
- ActiveRecord::Associations::CollectionAssociation
- Defined in:
- lib/active_record/associations/collection_association.rb
Overview
Active Record Association Collection
CollectionAssociation is an abstract class that provides common stuff to ease the implementation of association proxies that represent collections. See the class hierarchy in Association.
CollectionAssociation:
HasManyAssociation => has_many
HasManyThroughAssociation + ThroughAssociation => has_many :through
CollectionAssociation class provides common methods to the collections defined by has_and_belongs_to_many
, has_many
or has_many
with :through association option.
You need to be careful with assumptions regarding the target: The proxy does not fetch records from the database until it needs them, but new ones created with build
are added to the target. So, the target may be non-empty and still lack children waiting to be read from the database. If you look directly to the database you cannot assume that’s the entire collection because new records may have been added to the target, etc.
If you need to work on all current children, new and existing records, load_target
and the loaded
flag are your friends.
Direct Known Subclasses
Instance Attribute Summary
Attributes inherited from Association
#inversed, #owner, #reflection, #target
Instance Method Summary collapse
- #add_to_target(record, skip_callbacks = false, &block) ⇒ Object
-
#any? ⇒ Boolean
Returns true if the collections is not empty.
- #build(attributes = {}, &block) ⇒ Object
-
#concat(*records) ⇒ Object
Add
records
to this association. -
#count(column_name = nil, count_options = {}) ⇒ Object
Count all records using SQL.
- #create(attributes = {}, &block) ⇒ Object
- #create!(attributes = {}, &block) ⇒ Object
-
#delete(*records) ⇒ Object
Removes
records
from this association callingbefore_remove
andafter_remove
callbacks. -
#delete_all(dependent = nil) ⇒ Object
Removes all records from the association without calling callbacks on the associated records.
-
#destroy(*records) ⇒ Object
Deletes the
records
and removes them from this association callingbefore_remove
,after_remove
,before_destroy
andafter_destroy
callbacks. -
#destroy_all ⇒ Object
Destroy all the records from this association.
- #distinct ⇒ Object (also: #uniq)
-
#empty? ⇒ Boolean
Returns true if the collection is empty.
- #fifth(*args) ⇒ Object
- #find(*args) ⇒ Object
- #first(*args) ⇒ Object
- #forty_two(*args) ⇒ Object
- #fourth(*args) ⇒ Object
-
#ids_reader ⇒ Object
Implements the ids reader method, e.g.
-
#ids_writer(ids) ⇒ Object
Implements the ids writer method, e.g.
- #include?(record) ⇒ Boolean
- #last(*args) ⇒ Object
-
#length ⇒ Object
Returns the size of the collection calling
size
on the target. - #load_target ⇒ Object
-
#many? ⇒ Boolean
Returns true if the collection has more than 1 record.
- #null_scope? ⇒ Boolean
-
#reader(force_reload = false) ⇒ Object
Implements the reader method, e.g.
-
#replace(other_array) ⇒ Object
Replace this collection with
other_array
. - #replace_on_target(record, index, skip_callbacks) {|record| ... } ⇒ Object
- #reset ⇒ Object
- #scope(opts = {}) ⇒ Object
- #second(*args) ⇒ Object
- #select(*fields) ⇒ Object
-
#size ⇒ Object
Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn’t been loaded, and calling
collection.size
if it has. - #take(n = nil) ⇒ Object
- #third(*args) ⇒ Object
-
#transaction(*args) ⇒ Object
Starts a transaction in the association class’s database connection.
-
#writer(records) ⇒ Object
Implements the writer method, e.g.
Methods inherited from Association
#aliased_table_name, #association_scope, #initialize, #initialize_attributes, #interpolate, #klass, #loaded!, #loaded?, #marshal_dump, #marshal_load, #reload, #reset_scope, #set_inverse_instance, #stale_target?, #target_scope
Constructor Details
This class inherits a constructor from ActiveRecord::Associations::Association
Instance Method Details
#add_to_target(record, skip_callbacks = false, &block) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 399 def add_to_target(record, skip_callbacks = false, &block) if association_scope.distinct_value index = @target.index(record) end replace_on_target(record, index, skip_callbacks, &block) end |
#any? ⇒ Boolean
Returns true if the collections is not empty. Equivalent to !collection.empty?.
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# File 'lib/active_record/associations/collection_association.rb', line 336 def any? if block_given? load_target.any? { |*block_args| yield(*block_args) } else !empty? end end |
#build(attributes = {}, &block) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 142 def build(attributes = {}, &block) if attributes.is_a?(Array) attributes.collect { |attr| build(attr, &block) } else add_to_target(build_record(attributes)) do |record| yield(record) if block_given? end end end |
#concat(*records) ⇒ Object
Add records
to this association. Returns self
so method calls may be chained. Since << flattens its argument list and inserts each record, push
and concat
behave identically.
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# File 'lib/active_record/associations/collection_association.rb', line 163 def concat(*records) if owner.new_record? load_target concat_records(records) else transaction { concat_records(records) } end end |
#count(column_name = nil, count_options = {}) ⇒ Object
Count all records using SQL. Construct options and pass them with scope to the target class’s count
.
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# File 'lib/active_record/associations/collection_association.rb', line 231 def count(column_name = nil, = {}) # TODO: Remove count_options argument as soon we remove support to # activerecord-deprecated_finders. column_name, = nil, column_name if column_name.is_a?(Hash) relation = scope if association_scope.distinct_value # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL. column_name ||= reflection.klass.primary_key relation = relation.distinct end value = relation.count(column_name) limit = [:limit] offset = [:offset] if limit || offset [ [value - offset.to_i, 0].max, limit.to_i ].min else value end end |
#create(attributes = {}, &block) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 152 def create(attributes = {}, &block) _create_record(attributes, &block) end |
#create!(attributes = {}, &block) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 156 def create!(attributes = {}, &block) _create_record(attributes, true, &block) end |
#delete(*records) ⇒ Object
Removes records
from this association calling before_remove
and after_remove
callbacks.
This method is abstract in the sense that delete_records
has to be provided by descendants. Note this method does not imply the records are actually removed from the database, that depends precisely on delete_records
. They are in any case removed from the collection.
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# File 'lib/active_record/associations/collection_association.rb', line 262 def delete(*records) return if records.empty? = records. dependent = [:dependent] || [:dependent] records = find(records) if records.any? { |record| record.kind_of?(Fixnum) || record.kind_of?(String) } delete_or_destroy(records, dependent) end |
#delete_all(dependent = nil) ⇒ Object
Removes all records from the association without calling callbacks on the associated records. It honors the :dependent
option. However if the :dependent
value is :destroy
then in that case the :delete_all
deletion strategy for the association is applied.
You can force a particular deletion strategy by passing a parameter.
Example:
@author.books.delete_all(:nullify) @author.books.delete_all(:delete_all)
See delete for more info.
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# File 'lib/active_record/associations/collection_association.rb', line 200 def delete_all(dependent = nil) if dependent && ![:nullify, :delete_all].include?(dependent) raise ArgumentError, "Valid values are :nullify or :delete_all" end dependent = if dependent dependent elsif [:dependent] == :destroy :delete_all else [:dependent] end delete_or_nullify_all_records(dependent).tap do reset loaded! end end |
#destroy(*records) ⇒ Object
Deletes the records
and removes them from this association calling before_remove
, after_remove
, before_destroy
and after_destroy
callbacks.
Note that this method removes records from the database ignoring the :dependent
option.
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# File 'lib/active_record/associations/collection_association.rb', line 276 def destroy(*records) return if records.empty? records = find(records) if records.any? { |record| record.kind_of?(Fixnum) || record.kind_of?(String) } delete_or_destroy(records, :destroy) end |
#destroy_all ⇒ Object
Destroy all the records from this association.
See destroy for more info.
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# File 'lib/active_record/associations/collection_association.rb', line 222 def destroy_all destroy(load_target).tap do reset loaded! end end |
#distinct ⇒ Object Also known as: uniq
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# File 'lib/active_record/associations/collection_association.rb', line 354 def distinct seen = {} load_target.find_all do |record| seen[record.id] = true unless seen.key?(record.id) end end |
#empty? ⇒ Boolean
Returns true if the collection is empty.
If the collection has been loaded it is equivalent to collection.size.zero?
. If the collection has not been loaded, it is equivalent to collection.exists?
. If the collection has not already been loaded and you are going to fetch the records anyway it is better to check collection.length.zero?
.
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# File 'lib/active_record/associations/collection_association.rb', line 326 def empty? if loaded? size.zero? else @target.blank? && !scope.exists? end end |
#fifth(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 120 def fifth(*args) first_nth_or_last(:fifth, *args) end |
#find(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 83 def find(*args) if block_given? load_target.find(*args) { |*block_args| yield(*block_args) } else if [:inverse_of] && loaded? args_flatten = args.flatten raise RecordNotFound, "Couldn't find #{scope.klass.name} without an ID" if args_flatten.blank? result = find_by_scan(*args) result_size = Array(result).size if !result || result_size != args_flatten.size scope.raise_record_not_found_exception!(args_flatten, result_size, args_flatten.size) else result end else scope.find(*args) end end end |
#first(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 104 def first(*args) first_nth_or_last(:first, *args) end |
#forty_two(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 124 def forty_two(*args) first_nth_or_last(:forty_two, *args) end |
#fourth(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 116 def fourth(*args) first_nth_or_last(:fourth, *args) end |
#ids_reader ⇒ Object
Implements the ids reader method, e.g. foo.item_ids for Foo.has_many :items
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# File 'lib/active_record/associations/collection_association.rb', line 51 def ids_reader if loaded? load_target.map do |record| record.send(reflection.association_primary_key) end else column = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}" scope.pluck(column) end end |
#ids_writer(ids) ⇒ Object
Implements the ids writer method, e.g. foo.item_ids= for Foo.has_many :items
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# File 'lib/active_record/associations/collection_association.rb', line 63 def ids_writer(ids) pk_type = reflection.primary_key_type ids = Array(ids).reject { |id| id.blank? } ids.map! { |i| pk_type.type_cast_from_user(i) } replace(klass.find(ids).index_by { |r| r.id }.values_at(*ids)) end |
#include?(record) ⇒ Boolean
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# File 'lib/active_record/associations/collection_association.rb', line 378 def include?(record) if record.is_a?(reflection.klass) if record.new_record? include_in_memory?(record) else loaded? ? target.include?(record) : scope.exists?(record.id) end else false end end |
#last(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 128 def last(*args) first_nth_or_last(:last, *args) end |
#length ⇒ Object
Returns the size of the collection calling size
on the target.
If the collection has been already loaded length
and size
are equivalent. If not and you are going to need the records anyway this method will take one less query. Otherwise size
is more efficient.
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# File 'lib/active_record/associations/collection_association.rb', line 314 def length load_target.size end |
#load_target ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 390 def load_target if find_target? @target = merge_target_lists(find_target, target) end loaded! target end |
#many? ⇒ Boolean
Returns true if the collection has more than 1 record. Equivalent to collection.size > 1.
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# File 'lib/active_record/associations/collection_association.rb', line 346 def many? if block_given? load_target.many? { |*block_args| yield(*block_args) } else size > 1 end end |
#null_scope? ⇒ Boolean
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# File 'lib/active_record/associations/collection_association.rb', line 428 def null_scope? owner.new_record? && !foreign_key_present? end |
#reader(force_reload = false) ⇒ Object
Implements the reader method, e.g. foo.items for Foo.has_many :items
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# File 'lib/active_record/associations/collection_association.rb', line 29 def reader(force_reload = false) if force_reload klass.uncached { reload } elsif stale_target? reload end if owner.new_record? # Cache the proxy separately before the owner has an id # or else a post-save proxy will still lack the id @new_record_proxy ||= CollectionProxy.create(klass, self) else @proxy ||= CollectionProxy.create(klass, self) end end |
#replace(other_array) ⇒ Object
Replace this collection with other_array
. This will perform a diff and delete/add only records that have changed.
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# File 'lib/active_record/associations/collection_association.rb', line 364 def replace(other_array) other_array.each { |val| raise_on_type_mismatch!(val) } original_target = load_target.dup if owner.new_record? replace_records(other_array, original_target) else replace_common_records_in_memory(other_array, original_target) if other_array != original_target transaction { replace_records(other_array, original_target) } end end end |
#replace_on_target(record, index, skip_callbacks) {|record| ... } ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 406 def replace_on_target(record, index, skip_callbacks) callback(:before_add, record) unless skip_callbacks yield(record) if block_given? if index @target[index] = record else @target << record end callback(:after_add, record) unless skip_callbacks set_inverse_instance(record) record end |
#reset ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 70 def reset super @target = [] end |
#scope(opts = {}) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 422 def scope(opts = {}) scope = super() scope.none! if opts.fetch(:nullify, true) && null_scope? scope end |
#second(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 108 def second(*args) first_nth_or_last(:second, *args) end |
#select(*fields) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 75 def select(*fields) if block_given? load_target.select.each { |e| yield e } else scope.select(*fields) end end |
#size ⇒ Object
Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn’t been loaded, and calling collection.size
if it has.
If the collection has been already loaded size
and length
are equivalent. If not and you are going to need the records anyway length
will take one less query. Otherwise size
is more efficient.
This method is abstract in the sense that it relies on count_records
, which is a method descendants have to provide.
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# File 'lib/active_record/associations/collection_association.rb', line 292 def size if !find_target? || loaded? if association_scope.distinct_value target.uniq.size else target.size end elsif !loaded? && !association_scope.group_values.empty? load_target.size elsif !loaded? && !association_scope.distinct_value && target.is_a?(Array) unsaved_records = target.select { |r| r.new_record? } unsaved_records.size + count_records else count_records end end |
#take(n = nil) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 132 def take(n = nil) if loaded? n ? target.take(n) : target.first else scope.take(n).tap do |record| set_inverse_instance record if record.is_a? ActiveRecord::Base end end end |
#third(*args) ⇒ Object
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# File 'lib/active_record/associations/collection_association.rb', line 112 def third(*args) first_nth_or_last(:third, *args) end |
#transaction(*args) ⇒ Object
Starts a transaction in the association class’s database connection.
class Author < ActiveRecord::Base
has_many :books
end
Author.first.books.transaction do
# same effect as calling Book.transaction
end
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# File 'lib/active_record/associations/collection_association.rb', line 181 def transaction(*args) reflection.klass.transaction(*args) do yield end end |
#writer(records) ⇒ Object
Implements the writer method, e.g. foo.items= for Foo.has_many :items
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# File 'lib/active_record/associations/collection_association.rb', line 46 def writer(records) replace(records) end |