Class: ActiveRecord::Relation

Relationships & Source Files
Namespace Children
Modules: `RecordFetchWarning`
Classes: `FromClause`, `HashMerger`, `Merger`, `QueryAttribute`, `StrictLoadingScope`, `WhereClause`
Extension / Inclusion / Inheritance Descendants
Subclasses: AssociationRelation, DisableJoinsAssociationRelation, Associations::CollectionProxy
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, `FinderMethods`, `Calculations`, `SpawnMethods`, `QueryMethods`, `::ActiveModel::ForbiddenAttributesProtection`, `Batches`, `Explain`, `Delegation`, `::Enumerable`, `::ActiveSupport::EnumerableCoreExt::Constants`
Inherits:	Object
Defined in:	activerecord/lib/active_record/relation.rb, activerecord/lib/active_record/relation/from_clause.rb, activerecord/lib/active_record/relation/merger.rb, activerecord/lib/active_record/relation/query_attribute.rb, activerecord/lib/active_record/relation/record_fetch_warning.rb, activerecord/lib/active_record/relation/where_clause.rb

Constant Summary

CLAUSE_METHODS =
# File 'activerecord/lib/active_record/relation.rb', line 14
```
[:where, :having, :from]
```
INVALID_METHODS_FOR_DELETE_ALL =
# File 'activerecord/lib/active_record/relation.rb', line 15
```
[:distinct, :with]
```

MULTI_VALUE_METHODS =
# File 'activerecord/lib/active_record/relation.rb', line 6

[:includes, :eager_load, :preload, :select, :group,
:order, :joins, :left_outer_joins, :references,
:extending, :unscope, :optimizer_hints, :annotate,
:with]

SINGLE_VALUE_METHODS =
# File 'activerecord/lib/active_record/relation.rb', line 11

[:limit, :offset, :lock, :readonly, :reordering, :strict_loading,
:reverse_order, :distinct, :create_with, :skip_query_cache]

VALUE_METHODS =
# File 'activerecord/lib/active_record/relation.rb', line 17
```
MULTI_VALUE_METHODS + SINGLE_VALUE_METHODS + CLAUSE_METHODS
```

`Batches` - Included

DEFAULT_ORDER, ORDER_IGNORE_MESSAGE

`QueryMethods` - Included

FROZEN_EMPTY_ARRAY, FROZEN_EMPTY_HASH, STRUCTURAL_VALUE_METHODS, VALID_DIRECTIONS, VALID_UNSCOPING_VALUES

Class Method Summary

.new(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {}) ⇒ Relation constructor

Instance Attribute Summary

#blank? ⇒ Boolean readonly

Returns true if relation is blank.
#eager_loading? ⇒ Boolean readonly

Returns true if relation needs eager loading.
#empty? ⇒ Boolean readonly

Returns true if there are no records.
#klass (also: #model) readonly
#loaded? readonly

Alias for #loaded.
#many? ⇒ Boolean readonly

Returns true if there is more than one record.
#model readonly

Alias for #klass.
#predicate_builder readonly
#scheduled? ⇒ Boolean readonly

Returns true if the relation was scheduled on the background thread pool.
#skip_preloading_value rw
#table readonly
#references_eager_loaded_tables? ⇒ Boolean readonly private
#empty_scope? ⇒ Boolean readonly Internal use only
#has_limit_or_offset? ⇒ Boolean readonly Internal use only

`Delegation` - Included

#compact, #connection, #each, #encode_with, #in_groups, #in_groups_of, #index, #join, #length, #primary_key, #reverse, #rindex, #rotate, #sample, #shuffle, #slice, #split, #transaction

`::Enumerable` - Included

#many?

Returns true if the enumerable has more than 1 element.

Instance Method Summary

#==(other)

Compares two relations for equality.
#any?(*args) ⇒ Boolean

Returns true if there are any records.
#build(attributes = nil, &block)

Alias for #new.
#cache_key(timestamp_column = "updated_at")

Returns a stable cache key that can be used to identify this query.
#cache_key_with_version

Returns a cache key along with the version.
#cache_version(timestamp_column = :updated_at)

Returns a cache version that can be used together with the cache key to form a recyclable caching scheme.
#create(attributes = nil, &block)

Tries to create a new record with the same scoped attributes defined in the relation.
#create!(attributes = nil, &block)

Similar to #create, but calls create! on the base class.
#create_or_find_by(attributes, &block)

Attempts to create a record with the given attributes in a table that has a unique database constraint on one or several of its columns.
#create_or_find_by!(attributes, &block)

Like #create_or_find_by, but calls create! so an exception is raised if the created record is invalid.
#delete_all

Deletes the records without instantiating the records first, and hence not calling the #destroy method nor invoking callbacks.
#delete_by(*args)

Finds and deletes all records matching the specified conditions.
#destroy_all

Destroys the records by instantiating each record and calling its #destroy method.
#destroy_by(*args)

Finds and destroys all records matching the specified conditions.
#encode_with(coder)

Serializes the relation objects ::Array.
#explain(*options)

Runs EXPLAIN on the query or queries triggered by this relation and returns the result as a string.
#find_or_create_by(attributes, &block)

Finds the first record with the given attributes, or creates a record with the attributes if one is not found:
#find_or_create_by!(attributes, &block)

Like #find_or_create_by, but calls create! so an exception is raised if the created record is invalid.
#find_or_initialize_by(attributes, &block)

Like #find_or_create_by, but calls new instead of create.
#initialize_copy(other)
#inspect
#joined_includes_values

Joins that are also marked for preloading.
#load(&block)

Causes the records to be loaded from the database if they have not been loaded already.
#load_async

Schedule the query to be performed from a background thread pool.
#loaded (also: #loaded?) readonly
#locked?
#new(attributes = nil, &block) (also: #build)

Initializes new record from relation while maintaining the current scope.
#none?(*args) ⇒ Boolean

Returns true if there are no records.
#one?(*args) ⇒ Boolean

Returns true if there is exactly one record.
#pretty_print(pp)
#reload

Forces reloading of relation.
#reset
#scope_for_create
#scoping(all_queries: nil, &block)

Scope all queries to the current scope.
#size

Returns size of the records.
#to_a

Alias for #to_ary.
#to_ary (also: #to_a)

Converts relation objects to ::Array.
#to_sql

Returns sql statement for the relation.
#touch_all(*names, time: nil)

Touches all records in the current relation, setting the updated_at/updated_on attributes to the current time or the time specified.
#update_all(updates)

Updates all records in the current relation with details given.
#update_counters(counters)

Updates the counters of the records in the current relation.
#values
#load_records(records) protected
#_create(attributes, &block) private
#_create!(attributes, &block) private
#_increment_attribute(attribute, value = 1) private
#_new(attributes, &block) private
#_scoping(scope, registry, all_queries = false) private
#_substitute_values(values) private
#already_in_scope?(registry) ⇒ Boolean private
#current_scope_restoring_block(&block) private
#exec_main_query(async: false) private
#exec_queries(&block) private
#global_scope?(registry) ⇒ Boolean private
#instantiate_records(rows, &block) private
#limited_count private
#skip_query_cache_if_necessary(&block) private
#tables_in_string(string) private
#_exec_scope Internal use only
#alias_tracker(joins = [], aliases = nil) Internal use only
#bind_attribute(name, value) {|attr, bind| ... } Internal use only
#first_or_create(attributes = nil, &block) Internal use only
#first_or_create!(attributes = nil, &block) Internal use only
#first_or_initialize(attributes = nil, &block) Internal use only
#preload_associations(records) Internal use only
#records Internal use only
#update(id = :all, attributes) Internal use only
#update!(id = :all, attributes) Internal use only
#values_for_queries Internal use only
#where_values_hash(relation_table_name = klass.table_name) Internal use only

Returns a hash of where conditions.
#compute_cache_key(timestamp_column = :updated_at) private Internal use only
#compute_cache_version(timestamp_column) private Internal use only

`FinderMethods` - Included

#exists?	Returns true if a record exists in the table that matches the `id` or conditions given, or false otherwise.
#fifth	Find the fifth record.
#fifth!	Same as `#fifth` but raises `RecordNotFound` if no record is found.
#find	Find by id - This can either be a specific id (ID), a list of ids (ID, ID, ID), or an array of ids ([ID, ID, ID]).
#find_by	Finds the first record matching the specified conditions.
#find_by!	Like `#find_by`, except that if no record is found, raises an `RecordNotFound` error.
#find_sole_by	Finds the sole matching record.
#first	Find the first record (or first N records if a parameter is supplied).
#first!	Same as `#first` but raises `RecordNotFound` if no record is found.
#forty_two	Find the forty-second record.
#forty_two!	Same as `#forty_two` but raises `RecordNotFound` if no record is found.
#fourth	Find the fourth record.
#fourth!	Same as `#fourth` but raises `RecordNotFound` if no record is found.
#include?	Returns true if the relation contains the given record or false otherwise.
#last	Find the last record (or last N records if a parameter is supplied).
#last!	Same as `#last` but raises `RecordNotFound` if no record is found.
#member?	Alias for FinderMethods#include?.
#second	Find the second record.
#second!	Same as `#second` but raises `RecordNotFound` if no record is found.
#second_to_last	Find the second-to-last record.
#second_to_last!	Same as `#second_to_last` but raises `RecordNotFound` if no record is found.
#sole	Finds the sole matching record.
#take	Gives a record (or N records if a parameter is supplied) without any implied order.
#take!	Same as `#take` but raises `RecordNotFound` if no record is found.
#third	Find the third record.
#third!	Same as `#third` but raises `RecordNotFound` if no record is found.
#third_to_last	Find the third-to-last record.
#third_to_last!	Same as `#third_to_last` but raises `RecordNotFound` if no record is found.
#_order_columns, #apply_join_dependency, #construct_relation_for_exists, #find_last, #find_nth, #find_nth_from_last, #find_nth_with_limit, #find_one, #find_some, #find_some_ordered, #find_take, #find_take_with_limit, #find_with_ids, #ordered_relation, #using_limitable_reflections?,
#raise_record_not_found_exception!	This method is called whenever no records are found with either a single id or multiple ids and raises an `RecordNotFound` exception.

`Calculations` - Included

#async_average	Same as `#average`, but performs the query asynchronously and returns an `Promise`.
#async_count	Same as `#count`, but performs the query asynchronously and returns an `Promise`.
#async_ids	Same as `#ids`, but performs the query asynchronously and returns an `Promise`.
#async_maximum	Same as `#maximum`, but performs the query asynchronously and returns an `Promise`.
#async_minimum	Same as `#minimum`, but performs the query asynchronously and returns an `Promise`.
#async_pick	Same as `#pick`, but performs the query asynchronously and returns an `Promise`.
#async_pluck	Same as `#pluck`, but performs the query asynchronously and returns an `Promise`.
#async_sum	Same as `#sum`, but performs the query asynchronously and returns an `Promise`.
#average	Calculates the average value on a given column.
#calculate	This calculates aggregate values in the given column.
#count	Count the records.
#ids	Returns the base model’s ID’s for the relation using the table’s primary key.
#maximum	Calculates the maximum value on a given column.
#minimum	Calculates the minimum value on a given column.
#pick	Pick the value(s) from the named column(s) in the current relation.
#pluck	Use `#pluck` as a shortcut to select one or more attributes without loading an entire record object per row.
#sum	Calculates the sum of values on a given column.
#aggregate_column, #all_attributes?, #build_count_subquery, #distinct_select?, #has_include?, #lookup_cast_type_from_join_dependencies, #operation_over_aggregate_column, #perform_calculation, #select_for_count, #type_cast_calculated_value, #type_cast_pluck_values, #type_for, #execute_grouped_calculation, #execute_simple_calculation

`SpawnMethods` - Included

#except	Removes from the query the condition(s) specified in `skips`.
#merge	Merges in the conditions from `other`, if `other` is an `Relation`.
#only	Removes any condition from the query other than the one(s) specified in `onlies`.
#relation_with, #merge!, #spawn

`QueryMethods` - Included

#and	Returns a new relation, which is the logical intersection of this relation and the one passed as an argument.
#annotate	Adds an SQL comment to queries generated from this relation.
#create_with	Sets attributes to be used when creating new records from a relation object.
#distinct	Specifies whether the records should be unique or not.
#eager_load	Specify associations `args` to be eager loaded using a `LEFT OUTER JOIN`.
#excluding	Excludes the specified record (or collection of records) from the resulting relation.
#extending	Used to extend a scope with additional methods, either through a module or through a block provided.
#extensions,
#extract_associated	Extracts a named `association` from the relation.
#from	Specifies the table from which the records will be fetched.
#group	Allows to specify a group attribute:
#having	Allows to specify a HAVING clause.
#in_order_of	Allows to specify an order by a specific set of values.
#includes	Specify associations `args` to be eager loaded to prevent N + 1 queries.
#invert_where	Allows you to invert an entire where clause instead of manually applying conditions.
#joins	Performs JOINs on `args`.
#left_joins	Alias for QueryMethods#left_outer_joins.
#left_outer_joins	Performs LEFT OUTER JOINs on `args`:
#limit	Specifies a limit for the number of records to retrieve.
#lock	Specifies locking settings (default to `true`).
#none	Returns a chainable relation with zero records.
#offset	Specifies the number of rows to skip before returning rows.
#optimizer_hints	Specify optimizer hints to be used in the SELECT statement.
#or	Returns a new relation, which is the logical union of this relation and the one passed as an argument.
#order	Applies an `ORDER BY` clause to a query.
#preload	Specify associations `args` to be eager loaded using separate queries.
#readonly	Mark a relation as readonly.
#references	Use to indicate that the given `table_names` are referenced by an SQL string, and should therefore be `JOIN`ed in any query rather than loaded separately.
#regroup	Allows you to change a previously set group statement.
#reorder	Replaces any existing order defined on the relation with the specified order.
#reselect	Allows you to change a previously set select statement.
#reverse_order	Reverse the existing order clause on the relation.
#rewhere	Allows you to change a previously set where condition for a given attribute, instead of appending to that condition.
#select	Works in two unique ways.
#strict_loading	Sets the returned relation to strict_loading mode.
#structurally_compatible?	Checks whether the given relation is structurally compatible with this relation, to determine if it’s possible to use the `#and` and `#or` methods without raising an error.
#uniq!	Deduplicate multiple values.
#unscope	Removes an unwanted relation that is already defined on a chain of relations.
#where	Returns a new relation, which is the result of filtering the current relation according to the conditions in the arguments.
#with	Add a Common Table Expression (CTE) that you can then reference within another SELECT statement.
#without	Alias for QueryMethods#excluding.
#async!,
#build_having_clause	Alias for QueryMethods#build_where_clause.
#arel_column, #arel_columns, #assert_mutability!, #async, #build_arel, #build_case_for_value_position, #build_cast_value, #build_from, #build_join_buckets, #build_join_dependencies, #build_joins, #build_order, #build_select, #build_with, #build_with_join_node, #build_with_value_from_hash,
#check_if_method_has_arguments!	Checks to make sure that the arguments are not blank.
#column_references, #does_not_support_reverse?, #each_join_dependencies, #lookup_table_klass_from_join_dependencies, #order_column, #preprocess_order_args, #process_select_args, #resolve_arel_attributes, #reverse_sql_order, #sanitize_order_arguments, #select_association_list, #select_named_joins, #table_name_matches?, #transform_select_hash_values, #validate_order_args, #_select!, #and!,
#annotate!	Like `#annotate`, but modifies relation in place.
#arel	Returns the `::Arel` object associated with the relation.
#construct_join_dependency, #create_with!,
#distinct!	Like `#distinct`, but modifies relation in place.
#eager_load!, #excluding!, #extending!, #from!, #group!, #having!, #includes!, #invert_where!, #joins!, #left_outer_joins!, #limit!, #lock!, #none!, #offset!, #optimizer_hints!, #or!,
#order!	Same as `#order` but operates on relation in-place instead of copying.
#preload!, #readonly!, #references!,
#regroup!	Same as `#regroup` but operates on relation in-place instead of copying.
#reorder!	Same as `#reorder` but operates on relation in-place instead of copying.
#reselect!	Same as `#reselect` but operates on relation in-place instead of copying.
#reverse_order!, #skip_preloading!, #skip_query_cache!, #strict_loading!, #unscope!, #where!,
#with!	Like `#with`, but modifies relation in place.
#build_subquery, #build_where_clause, #structurally_incompatible_values_for

`::ActiveModel::ForbiddenAttributesProtection` - Included

#sanitize_for_mass_assignment,
#sanitize_forbidden_attributes	Alias for ActiveModel::ForbiddenAttributesProtection#sanitize_for_mass_assignment.

`Batches` - Included

#find_each	Looping through a collection of records from the database (using the Scoping::Named::ClassMethods#all method, for example) is very inefficient since it will try to instantiate all the objects at once.
#find_in_batches	Yields each batch of records that was found by the find options as an array.
#in_batches	Yields `Relation` objects to work with a batch of records.
#act_on_ignored_order, #apply_finish_limit, #apply_limits, #apply_start_limit, #batch_condition, #batch_on_loaded_relation, #batch_on_unloaded_relation, #build_batch_orders, #get_the_order_of_primary_key

`Explain` - Included

#build_explain_clause, #connection_explain, #render_bind,
#collecting_queries_for_explain	Executes the block with the collect flag enabled.
#exec_explain	Makes the adapter execute EXPLAIN for the tuples of queries and bindings.

`Delegation` - Included

#&, #+, #-, #[], #as_json, #intersect?, #to_formatted_s, #to_fs, #to_sentence, #to_xml, #|, #respond_to_missing?

`::Enumerable` - Included

#compact_blank	Returns a new `::Array` without the blank items.
#exclude?	The negative of the `Enumerable#include?`.
#excluding	Returns a copy of the enumerable excluding the specified elements.
#in_order_of	Returns a new `::Array` where the order has been set to that provided in the `series`, based on the `key` of the objects in the original enumerable.
#including	Returns a new array that includes the passed elements.
#index_by	Convert an enumerable to a hash, using the block result as the key and the element as the value.
#index_with	Convert an enumerable to a hash, using the element as the key and the block result as the value.
#maximum	Calculates the maximum from the extracted elements.
#minimum	Calculates the minimum from the extracted elements.
#pick	Extract the given key from the first element in the enumerable.
#pluck	Extract the given key from each element in the enumerable.
#sole	Returns the sole item in the enumerable.
#without	Alias for Enumerable#excluding.
#as_json

`::ActiveSupport::EnumerableCoreExt::Constants` - Included

#const_missing

Constructor Details

.new(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {}) ⇒ `Relation`

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 28


def initialize(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {})
  @klass  = klass
  @table  = table
  @values = values
  @loaded = false
  @predicate_builder = predicate_builder
  @delegate_to_klass = false
  @future_result = nil
  @records = nil
  @async = false
  @none = false
end

Instance Attribute Details

#blank? ⇒ `Boolean` (readonly)

Returns true if relation is blank.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 844


def blank?
  records.blank?
end

#eager_loading? ⇒ `Boolean` (readonly)

Returns true if relation needs eager loading.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 808


def eager_loading?
  @should_eager_load ||=
    eager_load_values.any? ||
    includes_values.any? && (joined_includes_values.any? || references_eager_loaded_tables?)
end

#empty? ⇒ `Boolean` (readonly)

Returns true if there are no records.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 283


def empty?
  return true if @none

  if loaded?
    records.empty?
  else
    !exists?
  end
end

#empty_scope? ⇒ `Boolean` (readonly)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 865


def empty_scope? # :nodoc:
  @values == klass.unscoped.values
end

#has_limit_or_offset? ⇒ `Boolean` (readonly)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 869


def has_limit_or_offset? # :nodoc:
  limit_value || offset_value
end

#klass (readonly) Also known as: #model

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 22


attr_reader :table, :klass, :loaded, :predicate_builder

#loaded? (readonly)

Alias for #loaded.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 25


alias :loaded? :loaded

#many? ⇒ `Boolean` (readonly)

Returns true if there is more than one record.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 334


def many?
  return false if @none

  return super if block_given?
  return records.many? if loaded?
  limited_count > 1
end

#model (readonly)

Alias for #klass.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 24


alias :model :klass

#predicate_builder (readonly)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 22


attr_reader :table, :klass, :loaded, :predicate_builder

#references_eager_loaded_tables? ⇒ `Boolean` (readonly, private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 1032


def references_eager_loaded_tables?
  joined_tables = build_joins([]).flat_map do |join|
    if join.is_a?(Arel::Nodes::StringJoin)
      tables_in_string(join.left)
    else
      join.left.name
    end
  end

  joined_tables << table.name

  # always convert table names to downcase as in Oracle quoted table names are in uppercase
  joined_tables.map!(&:downcase)

  !(references_values.map(&:to_s) - joined_tables).empty?
end

#scheduled? ⇒ `Boolean` (readonly)

Returns true if the relation was scheduled on the background thread pool.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 740


def scheduled?
  !!@future_result
end

#skip_preloading_value (rw)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 23


attr_accessor :skip_preloading_value

#table (readonly)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 22


attr_reader :table, :klass, :loaded, :predicate_builder

Instance Method Details

#==(other)

Compares two relations for equality.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 823


def ==(other)
  case other
  when Associations::CollectionProxy, AssociationRelation
    self == other.records
  when Relation
    other.to_sql == to_sql
  when Array
    records == other
  end
end

#_create(attributes, &block) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 923


def _create(attributes, &block)
  klass.create(attributes, &block)
end

#_create!(attributes, &block) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 927


def _create!(attributes, &block)
  klass.create!(attributes, &block)
end

#_exec_scope

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 471


def _exec_scope(...) # :nodoc:
  @delegate_to_klass = true
  registry = klass.scope_registry
  _scoping(nil, registry) { instance_exec(...) || self }
ensure
  @delegate_to_klass = false
end

#_increment_attribute(attribute, value = 1) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 958


def _increment_attribute(attribute, value = 1)
  bind = predicate_builder.build_bind_attribute(attribute.name, value.abs)
  expr = table.coalesce(Arel::Nodes::UnqualifiedColumn.new(attribute), 0)
  expr = value < 0 ? expr - bind : expr + bind
  expr.expr
end

#_new(attributes, &block) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 919


def _new(attributes, &block)
  klass.new(attributes, &block)
end

#_scoping(scope, registry, all_queries = false) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 931


def _scoping(scope, registry, all_queries = false)
  previous = registry.current_scope(klass, true)
  registry.set_current_scope(klass, scope)

  if all_queries
    previous_global = registry.global_current_scope(klass, true)
    registry.set_global_current_scope(klass, scope)
  end
  yield
ensure
  registry.set_current_scope(klass, previous)
  if all_queries
    registry.set_global_current_scope(klass, previous_global)
  end
end

#_substitute_values(values) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 947


def _substitute_values(values)
  values.map do |name, value|
    attr = table[name]
    unless Arel.arel_node?(value)
      type = klass.type_for_attribute(attr.name)
      value = predicate_builder.build_bind_attribute(attr.name, type.cast(value))
    end
    [attr, value]
  end
end

#alias_tracker(joins = [], aliases = nil)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 873


def alias_tracker(joins = [], aliases = nil) # :nodoc:
  ActiveRecord::Associations::AliasTracker.create(connection, table.name, joins, aliases)
end

#already_in_scope?(registry) ⇒ `Boolean` (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 903


def already_in_scope?(registry)
  @delegate_to_klass && registry.current_scope(klass, true)
end

#any?(*args) ⇒ `Boolean`

Returns true if there are any records.

When a pattern argument is given, this method checks whether elements in the ::Enumerable match the pattern via the case-equality operator (===).

posts.any?(Post) # => true or false

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 312


def any?(*args)
  return false if @none

  return super if args.present? || block_given?
  !empty?
end

#bind_attribute(name, value) {|attr, bind| ... }

This method is for internal use only.

Yields:

(attr, bind)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 46


def bind_attribute(name, value) # :nodoc:
  if reflection = klass._reflect_on_association(name)
    name = reflection.foreign_key
    value = value.read_attribute(reflection.association_primary_key) unless value.nil?
  end

  attr = table[name]
  bind = predicate_builder.build_bind_attribute(attr.name, value)
  yield attr, bind
end

#build(attributes = nil, &block)

Alias for #new.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 77


alias build new

#cache_key(timestamp_column = "updated_at")

Returns a stable cache key that can be used to identify this query. The cache key is built with a fingerprint of the SQL query.

Product.where("name like ?", "%Cosmic Encounter%").cache_key
# => "products/query-1850ab3d302391b85b8693e941286659"

If Base.collection_cache_versioning is turned off, as it was in Rails 6.0 and earlier, the cache key will also include a version.

ActiveRecord::Base.collection_cache_versioning = false
Product.where("name like ?", "%Cosmic Encounter%").cache_key
# => "products/query-1850ab3d302391b85b8693e941286659-1-20150714212553907087000"

You can also pass a custom timestamp column to fetch the timestamp of the last updated record.

Product.where("name like ?", "%Game%").cache_key(:last_reviewed_at)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 359


def cache_key(timestamp_column = "updated_at")
  @cache_keys ||= {}
  @cache_keys[timestamp_column] ||= klass.collection_cache_key(self, timestamp_column)
end

#cache_key_with_version

Returns a cache key along with the version.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 438


def cache_key_with_version
  if version = cache_version
    "#{cache_key}-#{version}"
  else
    cache_key
  end
end

#cache_version(timestamp_column = :updated_at)

Returns a cache version that can be used together with the cache key to form a recyclable caching scheme. The cache version is built with the number of records matching the query, and the timestamp of the last updated record. When a new record comes to match the query, or any of the existing records is updated or deleted, the cache version changes.

If the collection is loaded, the method will iterate through the records to generate the timestamp, otherwise it will trigger one SQL query like:

SELECT COUNT(*), MAX("products"."updated_at") FROM "products" WHERE (name like '%Cosmic Encounter%')

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 386


def cache_version(timestamp_column = :updated_at)
  if collection_cache_versioning
    @cache_versions ||= {}
    @cache_versions[timestamp_column] ||= compute_cache_version(timestamp_column)
  end
end

#compute_cache_key(timestamp_column = :updated_at) (private)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 364


def compute_cache_key(timestamp_column = :updated_at) # :nodoc:
  query_signature = ActiveSupport::Digest.hexdigest(to_sql)
  key = "#{klass.model_name.cache_key}/query-#{query_signature}"

  if collection_cache_versioning
    key
  else
    "#{key}-#{compute_cache_version(timestamp_column)}"
  end
end

#compute_cache_version(timestamp_column) (private)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 393


def compute_cache_version(timestamp_column) # :nodoc:
  timestamp_column = timestamp_column.to_s

  if loaded?
    size = records.size
    if size > 0
      timestamp = records.map { |record| record.read_attribute(timestamp_column) }.max
    end
  else
    collection = eager_loading? ? apply_join_dependency : self

    column = connection.visitor.compile(table[timestamp_column])
    select_values = "COUNT(*) AS #{connection.quote_column_name("size")}, MAX(%s) AS timestamp"

    if collection.has_limit_or_offset?
      query = collection.select("#{column} AS collection_cache_key_timestamp")
      query._select!(table[Arel.star]) if distinct_value && collection.select_values.empty?
      subquery_alias = "subquery_for_cache_key"
      subquery_column = "#{subquery_alias}.collection_cache_key_timestamp"
      arel = query.build_subquery(subquery_alias, select_values % subquery_column)
    else
      query = collection.unscope(:order)
      query.select_values = [select_values % column]
      arel = query.arel
    end

    size, timestamp = connection.select_rows(arel, nil).first

    if size
      column_type = klass.type_for_attribute(timestamp_column)
      timestamp = column_type.deserialize(timestamp)
    else
      size = 0
    end
  end

  if timestamp
    "#{size}-#{timestamp.utc.to_fs(cache_timestamp_format)}"
  else
    "#{size}"
  end
end

#create(attributes = nil, &block)

Tries to create a new record with the same scoped attributes defined in the relation. Returns the initialized object if validation fails.

Expects arguments in the same format as {ActiveRecord::Base.create}.

Examples

users = User.where(name: 'Oscar')
users.create # => #<User id: 3, name: "Oscar", ...>

users.create(name: 'fxn')
users.create # => #<User id: 4, name: "fxn", ...>

users.create { |user| user.name = 'tenderlove' }
# => #<User id: 5, name: "tenderlove", ...>

users.create(name: nil) # validation on name
# => #<User id: nil, name: nil, ...>

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 98


def create(attributes = nil, &block)
  if attributes.is_a?(Array)
    attributes.collect { |attr| create(attr, &block) }
  else
    block = current_scope_restoring_block(&block)
    scoping { _create(attributes, &block) }
  end
end

#create!(attributes = nil, &block)

Similar to #create, but calls create! on the base class. Raises an exception if a validation error occurs.

Expects arguments in the same format as {ActiveRecord::Base.create!}.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 113


def create!(attributes = nil, &block)
  if attributes.is_a?(Array)
    attributes.collect { |attr| create!(attr, &block) }
  else
    block = current_scope_restoring_block(&block)
    scoping { _create!(attributes, &block) }
  end
end

#create_or_find_by(attributes, &block)

Attempts to create a record with the given attributes in a table that has a unique database constraint on one or several of its columns. If a row already exists with one or several of these unique constraints, the exception such an insertion would normally raise is caught, and the existing record with those attributes is found using #find_by!.

This is similar to #find_or_create_by, but tries to create the record first. As such it is better suited for cases where the record is most likely not to exist yet.

There are several drawbacks to #create_or_find_by, though:

The underlying table must have the relevant columns defined with unique database constraints.
A unique constraint violation may be triggered by only one, or at least less than all, of the given attributes. This means that the subsequent #find_by! may fail to find a matching record, which will then raise an ActiveRecord::RecordNotFound exception, rather than a record with the given attributes.
While we avoid the race condition between SELECT -> INSERT from #find_or_create_by, we actually have another race condition between INSERT -> SELECT, which can be triggered if a DELETE between those two statements is run by another client. But for most applications, that’s a significantly less likely condition to hit.
It relies on exception handling to handle control flow, which may be marginally slower.
The primary key may auto-increment on each create, even if it fails. This can accelerate the problem of running out of integers, if the underlying table is still stuck on a primary key of type int (note: All Rails apps since 5.1+ have defaulted to bigint, which is not liable to this problem).

This method will return a record if all given attributes are covered by unique constraints (unless the INSERT -> DELETE -> SELECT race condition is triggered), but if creation was attempted and failed due to validation errors it won’t be persisted, you get what #create returns in such situation.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 215


def create_or_find_by(attributes, &block)
  transaction(requires_new: true) { create(attributes, &block) }
rescue ActiveRecord::RecordNotUnique
  if connection.transaction_open?
    where(attributes).lock.find_by!(attributes)
  else
    find_by!(attributes)
  end
end

#create_or_find_by!(attributes, &block)

Like #create_or_find_by, but calls create! so an exception is raised if the created record is invalid.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 228


def create_or_find_by!(attributes, &block)
  transaction(requires_new: true) { create!(attributes, &block) }
rescue ActiveRecord::RecordNotUnique
  if connection.transaction_open?
    where(attributes).lock.find_by!(attributes)
  else
    find_by!(attributes)
  end
end

#current_scope_restoring_block(&block) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 911


def current_scope_restoring_block(&block)
  current_scope = klass.current_scope(true)
  #=> record do
    klass.current_scope = current_scope
    yield record if block_given?
  end
end

#delete_all

Deletes the records without instantiating the records first, and hence not calling the #destroy method nor invoking callbacks. This is a single SQL DELETE statement that goes straight to the database, much more efficient than #destroy_all. Be careful with relations though, in particular :dependent rules defined on associations are not honored. Returns the number of rows affected.

Post.where(person_id: 5).where(category: ['Something', 'Else']).delete_all

Both calls delete the affected posts all at once with a single DELETE statement. If you need to destroy dependent associations or call your before_* or after_destroy callbacks, use the #destroy_all method instead.

If an invalid method is supplied, #delete_all raises an ActiveRecordError:

Post.distinct.delete_all
# => ActiveRecord::ActiveRecordError: delete_all doesn't support distinct

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 651


def delete_all
  return 0 if @none

  invalid_methods = INVALID_METHODS_FOR_DELETE_ALL.select do |method|
    value = @values[method]
    method == :distinct ? value : value&.any?
  end
  if invalid_methods.any?
    raise ActiveRecordError.new("delete_all doesn't support #{invalid_methods.join(', ')}")
  end

  arel = eager_loading? ? apply_join_dependency.arel : build_arel
  arel.source.left = table

  group_values_arel_columns = arel_columns(group_values.uniq)
  having_clause_ast = having_clause.ast unless having_clause.empty?
  key = if klass.composite_primary_key?
    primary_key.map { |pk| table[pk] }
  else
    table[primary_key]
  end
  stmt = arel.compile_delete(key, having_clause_ast, group_values_arel_columns)

  klass.connection.delete(stmt, "#{klass} Delete All").tap { reset }
end

#delete_by(*args)

Finds and deletes all records matching the specified conditions. This is short-hand for relation.where(condition).delete_all. Returns the number of rows affected.

If no record is found, returns 0 as zero rows were affected.

Person.delete_by(id: 13)
Person.delete_by(name: 'Spartacus', rating: 4)
Person.delete_by("published_at < ?", 2.weeks.ago)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 699


def delete_by(*args)
  where(*args).delete_all
end

#destroy_all

Destroys the records by instantiating each record and calling its #destroy method. Each object’s callbacks are executed (including :dependent association options). Returns the collection of objects that were destroyed; each will be frozen, to reflect that no changes should be made (since they can’t be persisted).

Note: Instantiation, callback execution, and deletion of each record can be time consuming when you’re removing many records at once. It generates at least one SQL DELETE query per record (or possibly more, to enforce your callbacks). If you want to delete many rows quickly, without concern for their associations or callbacks, use #delete_all instead.

Examples

Person.where(age: 0..18).destroy_all

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 629


def destroy_all
  records.each(&:destroy).tap { reset }
end

#destroy_by(*args)

Finds and destroys all records matching the specified conditions. This is short-hand for relation.where(condition).destroy_all. Returns the collection of objects that were destroyed.

If no record is found, returns empty array.

Person.destroy_by(id: 13)
Person.destroy_by(name: 'Spartacus', rating: 4)
Person.destroy_by("published_at < ?", 2.weeks.ago)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 686


def destroy_by(*args)
  where(*args).destroy_all
end

#encode_with(coder)

Serializes the relation objects ::Array.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 269


def encode_with(coder)
  coder.represent_seq(nil, records)
end

#exec_main_query(async: false) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 985


def exec_main_query(async: false)
  if @none
    if async
      return FutureResult.wrap([])
    else
      return []
    end
  end

  skip_query_cache_if_necessary do
    if where_clause.contradiction?
      [].freeze
    elsif eager_loading?
      apply_join_dependency do |relation, join_dependency|
        if relation.null_relation?
          [].freeze
        else
          relation = join_dependency.apply_column_aliases(relation)
          @_join_dependency = join_dependency
          connection.select_all(relation.arel, "SQL", async: async)
        end
      end
    else
      klass._query_by_sql(arel, async: async)
    end
  end
end

#exec_queries(&block) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 965


def exec_queries(&block)
  skip_query_cache_if_necessary do
    rows = if scheduled?
      future = @future_result
      @future_result = nil
      future.result
    else
      exec_main_query
    end

    records = instantiate_records(rows, &block)
    preload_associations(records) unless skip_preloading_value

    records.each(&:readonly!) if readonly_value
    records.each { |record| record.strict_loading!(strict_loading_value) } unless strict_loading_value.nil?

    records
  end
end

#explain(*options)

Runs EXPLAIN on the query or queries triggered by this relation and returns the result as a string. The string is formatted imitating the ones printed by the database shell.

Note that this method actually runs the queries, since the results of some are needed by the next ones when eager loading is going on.

Please see further details in the Active Record Query Interface guide.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 253


def explain(*options)
  exec_explain(collecting_queries_for_explain { exec_queries }, options)
end

#find_or_create_by(attributes, &block)

Finds the first record with the given attributes, or creates a record with the attributes if one is not found:

# Find the first user named "Penélope" or create a new one.
User.find_or_create_by(first_name: 'Penélope')
# => #<User id: 1, first_name: "Penélope", last_name: nil>

# Find the first user named "Penélope" or create a new one.
# We already have one so the existing record will be returned.
User.find_or_create_by(first_name: 'Penélope')
# => #<User id: 1, first_name: "Penélope", last_name: nil>

# Find the first user named "Scarlett" or create a new one with
# a particular last name.
User.create_with(last_name: 'Johansson').find_or_create_by(first_name: 'Scarlett')
# => #<User id: 2, first_name: "Scarlett", last_name: "Johansson">

This method accepts a block, which is passed down to #create. The last example above can be alternatively written this way:

# Find the first user named "Scarlett" or create a new one with a
# particular last name.
User.find_or_create_by(first_name: 'Scarlett') do |user|
  user.last_name = 'Johansson'
end
# => #<User id: 2, first_name: "Scarlett", last_name: "Johansson">

This method always returns a record, but if creation was attempted and failed due to validation errors it won’t be persisted, you get what #create returns in such situation.

If creation failed because of a unique constraint, this method will assume it encountered a race condition and will try finding the record once more. If somehow the second find still does not find a record because a concurrent DELETE happened, it will then raise an RecordNotFound exception.

Please note this method is not atomic, it runs first a SELECT, and if there are no results an INSERT is attempted. So if the table doesn’t have a relevant unique constraint it could be the case that you end up with two or more similar records.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 175


def find_or_create_by(attributes, &block)
  find_by(attributes) || create_or_find_by(attributes, &block)
end

#find_or_create_by!(attributes, &block)

Like #find_or_create_by, but calls create! so an exception is raised if the created record is invalid.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 182


def find_or_create_by!(attributes, &block)
  find_by(attributes) || create_or_find_by!(attributes, &block)
end

#find_or_initialize_by(attributes, &block)

Like #find_or_create_by, but calls new instead of create.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 240


def find_or_initialize_by(attributes, &block)
  find_by(attributes) || new(attributes, &block)
end

#first_or_create(attributes = nil, &block)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 122


def first_or_create(attributes = nil, &block) # :nodoc:
  first || create(attributes, &block)
end

#first_or_create!(attributes = nil, &block)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 126


def first_or_create!(attributes = nil, &block) # :nodoc:
  first || create!(attributes, &block)
end

#first_or_initialize(attributes = nil, &block)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 130


def first_or_initialize(attributes = nil, &block) # :nodoc:
  first || new(attributes, &block)
end

#global_scope?(registry) ⇒ `Boolean` (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 907


def global_scope?(registry)
  registry.global_current_scope(klass, true)
end

#initialize_copy(other)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 41


def initialize_copy(other)
  @values = @values.dup
  reset
end

#inspect

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 856


def inspect
  subject = loaded? ? records : annotate("loading for inspect")
  entries = subject.take([limit_value, 11].compact.min).map!(&:inspect)

  entries[10] = "..." if entries.size == 11

  "#<#{self.class.name} [#{entries.join(', ')}]>"
end

#instantiate_records(rows, &block) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 1013


def instantiate_records(rows, &block)
  return [].freeze if rows.empty?
  if eager_loading?
    records = @_join_dependency.instantiate(rows, strict_loading_value, &block).freeze
    @_join_dependency = nil
    records
  else
    klass._load_from_sql(rows, &block).freeze
  end
end

#joined_includes_values

Joins that are also marked for preloading. In which case we should just eager load them. Note that this is a naive implementation because we could have strings and symbols which represent the same association, but that aren’t matched by this. Also, we could have nested hashes which partially match, e.g. { a: :b } & { a: [:b, :c] }

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 818


def joined_includes_values
  includes_values & joins_values
end

#limited_count (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 1056


def limited_count
  limit_value ? count : limit(2).count
end

#load(&block)

Causes the records to be loaded from the database if they have not been loaded already. You can use this if for some reason you need to explicitly load some records before actually using them. The return value is the relation itself, not the records.

Post.where(published: true).load # => #<ActiveRecord::Relation>

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 750


def load(&block)
  if !loaded? || scheduled?
    @records = exec_queries(&block)
    @loaded = true
  end

  self
end

#load_async

Schedule the query to be performed from a background thread pool.

Post.where(published: true).load_async # => #<ActiveRecord::Relation>

When the Relation is iterated, if the background query wasn’t executed yet, it will be performed by the foreground thread.

Note that config.active_record.async_query_executor must be configured for queries to actually be executed concurrently. Otherwise it defaults to executing them in the foreground.

load_async will also fall back to executing in the foreground in the test environment when transactional fixtures are enabled.

If the query was actually executed in the background, the Active Record logs will show it by prefixing the log line with ASYNC:

ASYNC Post Load (0.0ms) (db time 2ms)  SELECT "posts".* FROM "posts" LIMIT 100

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 721


def load_async
  return load if !connection.async_enabled?

  unless loaded?
    result = exec_main_query(async: connection.current_transaction.closed?)

    if result.is_a?(Array)
      @records = result
    else
      @future_result = result
    end
    @loaded = true
  end

  self
end

#load_records(records) (protected)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 897


def load_records(records)
  @records = records.freeze
  @loaded = true
end

#loaded (readonly) Also known as: #loaded?

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 22


attr_reader :table, :klass, :loaded, :predicate_builder

#locked?

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 26


alias :locked? :lock_value

#new(attributes = nil, &block) Also known as: #build

Initializes new record from relation while maintaining the current scope.

Expects arguments in the same format as {ActiveRecord::Base.new}.

users = User.where(name: 'DHH')
user = users.new # => #<User id: nil, name: "DHH", created_at: nil, updated_at: nil>

You can also pass a block to new with the new record as argument:

user = users.new { |user| user.name = 'Oscar' }
user.name # => Oscar

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 69


def new(attributes = nil, &block)
  if attributes.is_a?(Array)
    attributes.collect { |attr| new(attr, &block) }
  else
    block = current_scope_restoring_block(&block)
    scoping { _new(attributes, &block) }
  end
end

#none?(*args) ⇒ `Boolean`

Returns true if there are no records.

When a pattern argument is given, this method checks whether elements in the ::Enumerable match the pattern via the case-equality operator (===).

posts.none?(Comment) # => true or false

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 299


def none?(*args)
  return true if @none

  return super if args.present? || block_given?
  empty?
end

#one?(*args) ⇒ `Boolean`

Returns true if there is exactly one record.

When a pattern argument is given, this method checks whether elements in the ::Enumerable match the pattern via the case-equality operator (===).

posts.one?(Post) # => true or false

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 325


def one?(*args)
  return false if @none

  return super if args.present? || block_given?
  return records.one? if loaded?
  limited_count == 1
end

#preload_associations(records)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 887


def preload_associations(records) # :nodoc:
  preload = preload_values
  preload += includes_values unless eager_loading?
  scope = strict_loading_value ? StrictLoadingScope : nil
  preload.each do |associations|
    ActiveRecord::Associations::Preloader.new(records: records, associations: associations, scope: scope).call
  end
end

#pretty_print(pp)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 834


def pretty_print(pp)
  subject = loaded? ? records : annotate("loading for pp")
  entries = subject.take([limit_value, 11].compact.min)

  entries[10] = "..." if entries.size == 11

  pp.pp(entries)
end

#records

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 263


def records # :nodoc:
  load
  @records
end

#reload

Forces reloading of relation.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 760


def reload
  reset
  load
end

#reset

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 765


def reset
  @future_result&.cancel
  @future_result = nil
  @delegate_to_klass = false
  @to_sql = @arel = @loaded = @should_eager_load = nil
  @offsets = @take = nil
  @cache_keys = nil
  @cache_versions = nil
  @records = nil
  self
end

#scope_for_create

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 801


def scope_for_create
  hash = where_clause.to_h(klass.table_name, equality_only: true)
  create_with_value.each { |k, v| hash[k.to_s] = v } unless create_with_value.empty?
  hash
end

#scoping(all_queries: nil, &block)

Scope all queries to the current scope.

Comment.where(post_id: 1).scoping do
  Comment.first
end
# SELECT "comments".* FROM "comments" WHERE "comments"."post_id" = 1 ORDER BY "comments"."id" ASC LIMIT 1

If all_queries: true is passed, scoping will apply to all queries for the relation including #update and delete on instances. Once all_queries is set to true it cannot be set to false in a nested block.

Please check unscoped if you want to remove all previous scopes (including the default_scope) during the execution of a block.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 460


def scoping(all_queries: nil, &block)
  registry = klass.scope_registry
  if global_scope?(registry) && all_queries == false
    raise ArgumentError, "Scoping is set to apply to all queries and cannot be unset in a nested block."
  elsif already_in_scope?(registry)
    yield
  else
    _scoping(self, registry, all_queries, &block)
  end
end

#size

Returns size of the records.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 274


def size
  if loaded?
    records.length
  else
    count(:all)
  end
end

#skip_query_cache_if_necessary(&block) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 1024


def skip_query_cache_if_necessary(&block)
  if skip_query_cache_value
    uncached(&block)
  else
    yield
  end
end

#tables_in_string(string) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 1049


def tables_in_string(string)
  return [] if string.blank?
  # always convert table names to downcase as in Oracle quoted table names are in uppercase
  # ignore raw_sql_ that is used by Oracle adapter as alias for limit/offset subqueries
  string.scan(/[a-zA-Z_][.\w]+(?=.?\.)/).map!(&:downcase) - ["raw_sql_"]
end

#to_a

Alias for #to_ary.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 261


alias to_a to_ary

#to_ary Also known as: #to_a

Converts relation objects to ::Array.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 258


def to_ary
  records.dup
end

#to_sql

Returns sql statement for the relation.

User.where(name: 'Oscar').to_sql
# SELECT "users".* FROM "users"  WHERE "users"."name" = 'Oscar'

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 781


def to_sql
  @to_sql ||= if eager_loading?
    apply_join_dependency do |relation, join_dependency|
      relation = join_dependency.apply_column_aliases(relation)
      relation.to_sql
    end
  else
    conn = klass.connection
    conn.unprepared_statement { conn.to_sql(arel) }
  end
end

#touch_all(*names, time: nil)

Touches all records in the current relation, setting the updated_at/updated_on attributes to the current time or the time specified. It does not instantiate the involved models, and it does not trigger Active Record callbacks or validations. This method can be passed attribute names and an optional time argument. If attribute names are passed, they are updated along with updated_at/updated_on attributes. If no time argument is passed, the current time is used as default.

Examples

# Touch all records
Person.all.touch_all
# => "UPDATE \"people\" SET \"updated_at\" = '2018-01-04 22:55:23.132670'"

# Touch multiple records with a custom attribute
Person.all.touch_all(:created_at)
# => "UPDATE \"people\" SET \"updated_at\" = '2018-01-04 22:55:23.132670', \"created_at\" = '2018-01-04 22:55:23.132670'"

# Touch multiple records with a specified time
Person.all.touch_all(time: Time.new(2020, 5, 16, 0, 0, 0))
# => "UPDATE \"people\" SET \"updated_at\" = '2020-05-16 00:00:00'"

# Touch records with scope
Person.where(name: 'David').touch_all
# => "UPDATE \"people\" SET \"updated_at\" = '2018-01-04 22:55:23.132670' WHERE \"people\".\"name\" = 'David'"

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 609


def touch_all(*names, time: nil)
  update_all klass.touch_attributes_with_time(*names, time: time)
end

#update(id = :all, attributes)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 538


def update(id = :all, attributes) # :nodoc:
  if id == :all
    each { |record| record.update(attributes) }
  else
    klass.update(id, attributes)
  end
end

#update!(id = :all, attributes)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 546


def update!(id = :all, attributes) # :nodoc:
  if id == :all
    each { |record| record.update!(attributes) }
  else
    klass.update!(id, attributes)
  end
end

#update_all(updates)

Updates all records in the current relation with details given. This method constructs a single SQL UPDATE statement and sends it straight to the database. It does not instantiate the involved models and it does not trigger Active Record callbacks or validations. However, values passed to #update_all will still go through Active Record’s normal type casting and serialization. Returns the number of rows affected.

Note: As Active Record callbacks are not triggered, this method will not automatically update updated_at/updated_on columns.

Parameters

updates - A string, array, or hash representing the SET part of an SQL statement. Any strings provided will be type cast, unless you use Arel.sql. (Don’t pass user-provided values to Arel.sql.)

Examples

# Update all customers with the given attributes
Customer.update_all wants_email: true

# Update all books with 'Rails' in their title
Book.where('title LIKE ?', '%Rails%').update_all(author: 'David')

# Update all books that match conditions, but limit it to 5 ordered by date
Book.where('title LIKE ?', '%Rails%').order(:created_at).limit(5).update_all(author: 'David')

# Update all invoices and set the number column to its id value.
Invoice.update_all('number = id')

# Update all books with 'Rails' in their title
Book.where('title LIKE ?', '%Rails%').update_all(title: Arel.sql("title + ' - volume 1'"))

Raises:

(ArgumentError)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 507


def update_all(updates)
  raise ArgumentError, "Empty list of attributes to change" if updates.blank?

  return 0 if @none

  if updates.is_a?(Hash)
    if klass.locking_enabled? &&
        !updates.key?(klass.locking_column) &&
        !updates.key?(klass.locking_column.to_sym)
      attr = table[klass.locking_column]
      updates[attr.name] = _increment_attribute(attr)
    end
    values = _substitute_values(updates)
  else
    values = Arel.sql(klass.sanitize_sql_for_assignment(updates, table.name))
  end

  arel = eager_loading? ? apply_join_dependency.arel : build_arel
  arel.source.left = table

  group_values_arel_columns = arel_columns(group_values.uniq)
  having_clause_ast = having_clause.ast unless having_clause.empty?
  key = if klass.composite_primary_key?
    primary_key.map { |pk| table[pk] }
  else
    table[primary_key]
  end
  stmt = arel.compile_update(values, key, having_clause_ast, group_values_arel_columns)
  klass.connection.update(stmt, "#{klass} Update All").tap { reset }
end

#update_counters(counters)

Updates the counters of the records in the current relation.

Parameters

counter - A Hash containing the names of the fields to update as keys and the amount to update as values.
:touch option - Touch the timestamp columns when updating.
If attributes names are passed, they are updated along with update_at/on attributes.

Examples

# For Posts by a given author increment the comment_count by 1.
Post.where(author_id: author.id).update_counters(comment_count: 1)

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 566


def update_counters(counters)
  touch = counters.delete(:touch)

  updates = {}
  counters.each do |counter_name, value|
    attr = table[counter_name]
    updates[attr.name] = _increment_attribute(attr, value)
  end

  if touch
    names = touch if touch != true
    names = Array.wrap(names)
    options = names.extract_options!
    touch_updates = klass.touch_attributes_with_time(*names, **options)
    updates.merge!(touch_updates) unless touch_updates.empty?
  end

  update_all updates
end

#values

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 848


def values
  @values.dup
end

#values_for_queries

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 852


def values_for_queries # :nodoc:
  @values.except(:extending, :skip_query_cache, :strict_loading)
end

#where_values_hash(relation_table_name = klass.table_name)

This method is for internal use only.

Returns a hash of where conditions.

User.where(name: 'Oscar').where_values_hash
# => {name: "Oscar"}

[ GitHub ]

# File 'activerecord/lib/active_record/relation.rb', line 797


def where_values_hash(relation_table_name = klass.table_name) # :nodoc:
  where_clause.to_h(relation_table_name)
end

Class: ActiveRecord::Relation

Constant Summary

Batches - Included

QueryMethods - Included

FinderMethods - Included

Class Method Summary

Instance Attribute Summary

QueryMethods - Included

Delegation - Included

::Enumerable - Included

Instance Method Summary

FinderMethods - Included

Calculations - Included

SpawnMethods - Included

QueryMethods - Included

::ActiveModel::ForbiddenAttributesProtection - Included

Batches - Included

Explain - Included

Delegation - Included

::Enumerable - Included

::ActiveSupport::EnumerableCoreExt::Constants - Included

Constructor Details

.new(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {}) ⇒ Relation

Instance Attribute Details

#blank? ⇒ Boolean (readonly)

#eager_loading? ⇒ Boolean (readonly)

#empty? ⇒ Boolean (readonly)

#empty_scope? ⇒ Boolean (readonly)

#has_limit_or_offset? ⇒ Boolean (readonly)

#klass (readonly) Also known as: #model

#loaded? (readonly)

#many? ⇒ Boolean (readonly)

#model (readonly)

#predicate_builder (readonly)

#references_eager_loaded_tables? ⇒ Boolean (readonly, private)

#scheduled? ⇒ Boolean (readonly)

#skip_preloading_value (rw)

#table (readonly)

Instance Method Details

#==(other)

#_create(attributes, &block) (private)

#_create!(attributes, &block) (private)

#_exec_scope

#_increment_attribute(attribute, value = 1) (private)

#_new(attributes, &block) (private)

#_scoping(scope, registry, all_queries = false) (private)

#_substitute_values(values) (private)

#alias_tracker(joins = [], aliases = nil)

#already_in_scope?(registry) ⇒ Boolean (private)

#any?(*args) ⇒ Boolean

#bind_attribute(name, value) {|attr, bind| ... }

#build(attributes = nil, &block)

#cache_key(timestamp_column = "updated_at")

#cache_key_with_version

#cache_version(timestamp_column = :updated_at)

#compute_cache_key(timestamp_column = :updated_at) (private)

#compute_cache_version(timestamp_column) (private)

#create(attributes = nil, &block)

Examples

#create!(attributes = nil, &block)

#create_or_find_by(attributes, &block)

#create_or_find_by!(attributes, &block)

#current_scope_restoring_block(&block) (private)

#delete_all

#delete_by(*args)

#destroy_all

Examples

#destroy_by(*args)

#encode_with(coder)

#exec_main_query(async: false) (private)

#exec_queries(&block) (private)

#explain(*options)

#find_or_create_by(attributes, &block)

#find_or_create_by!(attributes, &block)

#find_or_initialize_by(attributes, &block)

#first_or_create(attributes = nil, &block)

#first_or_create!(attributes = nil, &block)

#first_or_initialize(attributes = nil, &block)

#global_scope?(registry) ⇒ Boolean (private)

#initialize_copy(other)

`Batches` - Included

`QueryMethods` - Included

`FinderMethods` - Included

`QueryMethods` - Included

`Delegation` - Included

`::Enumerable` - Included

`FinderMethods` - Included

`Calculations` - Included

`SpawnMethods` - Included

`QueryMethods` - Included

`::ActiveModel::ForbiddenAttributesProtection` - Included

`Batches` - Included

`Explain` - Included

`Delegation` - Included

`::Enumerable` - Included

`::ActiveSupport::EnumerableCoreExt::Constants` - Included

.new(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {}) ⇒ `Relation`

#blank? ⇒ `Boolean` (readonly)

#eager_loading? ⇒ `Boolean` (readonly)

#empty? ⇒ `Boolean` (readonly)

#empty_scope? ⇒ `Boolean` (readonly)

#has_limit_or_offset? ⇒ `Boolean` (readonly)

#many? ⇒ `Boolean` (readonly)

#references_eager_loaded_tables? ⇒ `Boolean` (readonly, private)

#scheduled? ⇒ `Boolean` (readonly)

#already_in_scope?(registry) ⇒ `Boolean` (private)

#any?(*args) ⇒ `Boolean`

#global_scope?(registry) ⇒ `Boolean` (private)

#none?(*args) ⇒ `Boolean`

#one?(*args) ⇒ `Boolean`