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Class: ActiveRecord::Relation

Constant Summary

Batches - Included

DEFAULT_ORDER, ORDER_IGNORE_MESSAGE

QueryMethods - Included

FROZEN_EMPTY_ARRAY, FROZEN_EMPTY_HASH, STRUCTURAL_VALUE_METHODS, VALID_DIRECTIONS, VALID_UNSCOPING_VALUES

FinderMethods - Included

ONE_AS_ONE

Class Method Summary

Instance Attribute Summary

QueryMethods - Included

Delegation - Included

::Enumerable - Included

#many?

Returns true if the enumerable has more than 1 element.

Instance Method Summary

SignedId::RelationMethods - Included

TokenFor::RelationMethods - Included

#find_by_token_for

Finds a record using a given token for a predefined purpose.

#find_by_token_for!

Finds a record using a given token for a predefined purpose.

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?
#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, #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

Applies an ORDER BY clause based on a given column, ordered and filtered 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
#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 JOINed 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.

#with_recursive

Add a recursive Common Table Expression (CTE) that you can then reference within another SELECT statement.

#without
#arel_columns, #async!,
#build_having_clause
#arel_column, #arel_column_aliases_from_hash, #arel_column_with_table, #arel_columns_from_hash, #assert_modifiable!, #async, #build_arel, #build_bound_sql_literal, #build_case_for_value_position, #build_cast_value, #build_from, #build_join_buckets, #build_join_dependencies, #build_joins, #build_named_bound_sql_literal, #build_order, #build_select, #build_with, #build_with_expression_from_value, #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, #extract_table_name_from, #flattened_args, #lookup_table_klass_from_join_dependencies, #order_column, #preprocess_order_args, #process_select_args, #process_with_args, #resolve_arel_attributes, #reverse_sql_order, #sanitize_order_arguments, #select_association_list, #select_named_joins, #table_name_matches?, #validate_order_args, #_select!, #all, #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.

#with_recursive!

Like #with_recursive but modifies the relation in place.

#build_subquery, #build_where_clause, #structurally_incompatible_values_for

::ActiveModel::ForbiddenAttributesProtection - Included

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,
#compare_values_for_order

This is a custom implementation of <=> operator, which also takes into account how the collection will be ordered.

#ensure_valid_options_for_batching!, #record_cursor_values

Explain - Included

#build_explain_clause, #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

::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
#as_json

::ActiveSupport::EnumerableCoreExt::Constants - Included

Constructor Details

.new(model, table: nil, predicate_builder: nil, values: {}) ⇒ Relation

[ GitHub ]

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

def initialize(model, table: nil, predicate_builder: nil, values: {})
  if table
    predicate_builder ||= model.predicate_builder.with(TableMetadata.new(model, table))
  else
    table = model.arel_table
    predicate_builder ||= model.predicate_builder
  end

  @model  = model
  @table  = table
  @values = values
  @loaded = false
  @predicate_builder = predicate_builder
  @delegate_to_model = 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 1274

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 1238

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 362

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 1299

def empty_scope? # :nodoc:
  @values == model.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 1303

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

#klass (readonly)

Alias for #model.

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 73

alias :klass :model

#loaded? (readonly)

Alias for #loaded.

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 74

alias :loaded? :loaded

#many?Boolean (readonly)

Returns true if there is more than one record.

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 413

def many?
  return false if @none

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

#model (readonly) Also known as: #klass

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 71

attr_reader :table, :model, :loaded, :predicate_builder

#predicate_builder (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 71

attr_reader :table, :model, :loaded, :predicate_builder

#readonly?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1278

def readonly?
  readonly_value
end

#references_eager_loaded_tables?Boolean (readonly, private)

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1474

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 1169

def scheduled?
  !!@future_result
end

#skip_preloading_value (rw)

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 72

attr_accessor :skip_preloading_value

#table (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 71

attr_reader :table, :model, :loaded, :predicate_builder

Instance Method Details

#==(other)

Compares two relations for equality.

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1253

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 1357

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

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

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1361

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

#_exec_scope

This method is for internal use only.
[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 552

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

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

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1396

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 1353

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

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

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1365

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

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

#_substitute_values(values) (private)

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1381

def _substitute_values(values)
  values.map do |name, value|
    attr = table[name]
    if Arel.arel_node?(value)
      if value.is_a?(Arel::Nodes::SqlLiteral)
        value = Arel::Nodes::Grouping.new(value)
      end
    else
      type = model.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 1307

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

#already_in_scope?(registry) ⇒ Boolean (private)

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1337

def already_in_scope?(registry)
  @delegate_to_model && registry.current_scope(model, 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 391

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 102

def bind_attribute(name, value) # :nodoc:
  if reflection = model._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 133

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 438

def cache_key(timestamp_column = "updated_at")
  @cache_keys ||= {}
  @cache_keys[timestamp_column] ||= model.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 519

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 465

def cache_version(timestamp_column = :updated_at)
  if model.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 443

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

  if model.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 472

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

    with_connection do |c|
      column = c.visitor.compile(table[timestamp_column])
      select_values = "COUNT(*) AS #{model.adapter_class.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 = c.select_rows(arel, nil).first

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

  if timestamp
    "#{size}-#{timestamp.utc.to_fs(model.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 154

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 169

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).

  • Columns with unique database constraints should not have uniqueness validations defined, otherwise #create will fail due to validation errors and #find_by will never be called.

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 273

def create_or_find_by(attributes, &block)
  with_connection do |connection|
    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
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 288

def create_or_find_by!(attributes, &block)
  with_connection do |connection|
    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
end

#current_scope_restoring_block(&block) (private)

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# File 'activerecord/lib/active_record/relation.rb', line 1345

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

#delete(id_or_array)

Deletes the row with a primary key matching the id argument, using an SQL DELETE statement, and returns the number of rows deleted. Active Record objects are not instantiated, so the object’s callbacks are not executed, including any :dependent association options.

You can delete multiple rows at once by passing an ::Array of ids.

Note: Although it is often much faster than the alternative, #destroy, skipping callbacks might bypass business logic in your application that ensures referential integrity or performs other essential jobs.

Examples

# Delete a single row
Todo.delete(1)

# Delete multiple rows
Todo.delete([2,3,4])
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# File 'activerecord/lib/active_record/relation.rb', line 1057

def delete(id_or_array)
  return 0 if id_or_array.nil? || (id_or_array.is_a?(Array) && id_or_array.empty?)

  where(model.primary_key => id_or_array).delete_all
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 1011

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

  model.with_connection do |c|
    arel = eager_loading? ? apply_join_dependency.arel : build_arel(c)
    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 model.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)

    c.delete(stmt, "#{model} Delete All").tap { reset }
  end
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 1119

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

#destroy(id)

Destroy an object (or multiple objects) that has the given id. The object is instantiated first, therefore all callbacks and filters are fired off before the object is deleted. This method is less efficient than #delete but allows cleanup methods and other actions to be run.

This essentially finds the object (or multiple objects) with the given id, creates a new object from the attributes, and then calls destroy on it.

Parameters

  • id - This should be the id or an array of ids to be destroyed.

Examples

# Destroy a single object
Todo.destroy(1)

# Destroy multiple objects
todos = [1,2,3]
Todo.destroy(todos)
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# File 'activerecord/lib/active_record/relation.rb', line 1083

def destroy(id)
  multiple_ids = if model.composite_primary_key?
    id.first.is_a?(Array)
  else
    id.is_a?(Array)
  end

  if multiple_ids
    find(id).each(&:destroy)
  else
    find(id).destroy
  end
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
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# File 'activerecord/lib/active_record/relation.rb', line 989

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 1106

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 348

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

#exec_main_query(async: false) (private)

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# File 'activerecord/lib/active_record/relation.rb', line 1423

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?
      model.with_connection do |c|
        apply_join_dependency do |relation, join_dependency|
          if relation.null_relation?
            [].freeze
          else
            relation = join_dependency.apply_column_aliases(relation)
            @_join_dependency = join_dependency
            c.select_all(relation.arel, "SQL", async: async)
          end
        end
      end
    else
      model.with_connection do |c|
        model._query_by_sql(c, arel, async: async)
      end
    end
  end
end

#exec_queries(&block) (private)

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# File 'activerecord/lib/active_record/relation.rb', line 1403

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.

User.all.explain
# EXPLAIN SELECT {users}.* FROM {users}
# ...

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.

To run EXPLAIN on queries created by first, pluck and count, call these methods on explain:

User.all.explain.count
# EXPLAIN SELECT COUNT(*) FROM {users}
# ...

The column name can be passed if required:

User.all.explain.maximum(:id)
# EXPLAIN SELECT MAX(`users`.`id`) FROM {users}
# ...

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

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 332

def explain(*options)
  ExplainProxy.new(self, 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 231

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 238

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 302

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 178

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 182

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 186

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

#global_scope?(registry) ⇒ Boolean (private)

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# File 'activerecord/lib/active_record/relation.rb', line 1341

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

#initialize_copy(other)

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# File 'activerecord/lib/active_record/relation.rb', line 97

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

#insert(attributes, returning: nil, unique_by: nil, record_timestamps: nil)

Inserts a single record into the database in a single SQL INSERT statement. It does not instantiate any models nor does it trigger Active Record callbacks or validations. Though passed values go through Active Record’s type casting and serialization.

See #insert_all for documentation.

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 644

def insert(attributes, returning: nil, unique_by: nil, record_timestamps: nil)
  insert_all([ attributes ], returning: returning, unique_by: unique_by, record_timestamps: record_timestamps)
end

#insert!(attributes, returning: nil, record_timestamps: nil)

Inserts a single record into the database in a single SQL INSERT statement. It does not instantiate any models nor does it trigger Active Record callbacks or validations. Though passed values go through Active Record’s type casting and serialization.

See #insert_all! for more.

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 733

def insert!(attributes, returning: nil, record_timestamps: nil)
  insert_all!([ attributes ], returning: returning, record_timestamps: record_timestamps)
end

#insert_all(attributes, returning: nil, unique_by: nil, record_timestamps: nil)

Inserts multiple records into the database in a single SQL INSERT statement. It does not instantiate any models nor does it trigger Active Record callbacks or validations. Though passed values go through Active Record’s type casting and serialization.

The attributes parameter is an ::Array of Hashes. Every Hash determines the attributes for a single row and must have the same keys.

Rows are considered to be unique by every unique index on the table. Any duplicate rows are skipped. Override with :unique_by (see below).

Returns an Result with its contents based on :returning (see below).

Options

:returning

(PostgreSQL, SQLite3, and MariaDB only) An array of attributes to return for all successfully inserted records, which by default is the primary key. Pass returning: %w[ id name ] for both id and name or returning: false to omit the underlying RETURNING SQL clause entirely.

You can also pass an SQL string if you need more control on the return values (for example, returning: Arel.sql("id, name as new_name")).

:unique_by

(PostgreSQL and SQLite only) By default rows are considered to be unique by every unique index on the table. Any duplicate rows are skipped.

To skip rows according to just one unique index pass :unique_by.

Consider a Book model where no duplicate ISBNs make sense, but if any row has an existing id, or is not unique by another unique index, ActiveRecord::RecordNotUnique is raised.

Unique indexes can be identified by columns or name:

unique_by: :isbn
unique_by: %i[ author_id name ]
unique_by: :index_books_on_isbn
:record_timestamps

By default, automatic setting of timestamp columns is controlled by the model’s record_timestamps config, matching typical behavior.

To override this and force automatic setting of timestamp columns one way or the other, pass :record_timestamps:

record_timestamps: true  # Always set timestamps automatically
record_timestamps: false # Never set timestamps automatically

Because it relies on the index information from the database :unique_by is recommended to be paired with Active Record’s schema_cache.

Example

# Insert records and skip inserting any duplicates.
# Here "Eloquent Ruby" is skipped because its id is not unique.

Book.insert_all([
  { id: 1, title: "Rework", author: "David" },
  { id: 1, title: "Eloquent Ruby", author: "Russ" }
])

# insert_all works on chained scopes, and you can use create_with
# to set default attributes for all inserted records.

author.books.create_with(created_at: Time.now).insert_all([
  { id: 1, title: "Rework" },
  { id: 2, title: "Eloquent Ruby" }
])
[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 723

def insert_all(attributes, returning: nil, unique_by: nil, record_timestamps: nil)
  InsertAll.execute(self, attributes, on_duplicate: :skip, returning: returning, unique_by: unique_by, record_timestamps: record_timestamps)
end

#insert_all!(attributes, returning: nil, record_timestamps: nil)

Inserts multiple records into the database in a single SQL INSERT statement. It does not instantiate any models nor does it trigger Active Record callbacks or validations. Though passed values go through Active Record’s type casting and serialization.

The attributes parameter is an ::Array of Hashes. Every Hash determines the attributes for a single row and must have the same keys.

Raises RecordNotUnique if any rows violate a unique index on the table. In that case, no rows are inserted.

To skip duplicate rows, see #insert_all. To replace them, see #upsert_all.

Returns an Result with its contents based on :returning (see below).

Options

:returning

(PostgreSQL, SQLite3, and MariaDB only) An array of attributes to return for all successfully inserted records, which by default is the primary key. Pass returning: %w[ id name ] for both id and name or returning: false to omit the underlying RETURNING SQL clause entirely.

You can also pass an SQL string if you need more control on the return values (for example, returning: Arel.sql("id, name as new_name")).

:record_timestamps

By default, automatic setting of timestamp columns is controlled by the model’s record_timestamps config, matching typical behavior.

To override this and force automatic setting of timestamp columns one way or the other, pass :record_timestamps:

record_timestamps: true  # Always set timestamps automatically
record_timestamps: false # Never set timestamps automatically

Examples

# Insert multiple records
Book.insert_all!([
  { title: "Rework", author: "David" },
  { title: "Eloquent Ruby", author: "Russ" }
])

# Raises ActiveRecord::RecordNotUnique because "Eloquent Ruby"
# does not have a unique id.
Book.insert_all!([
  { id: 1, title: "Rework", author: "David" },
  { id: 1, title: "Eloquent Ruby", author: "Russ" }
])
[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 790

def insert_all!(attributes, returning: nil, record_timestamps: nil)
  InsertAll.execute(self, attributes, on_duplicate: :raise, returning: returning, record_timestamps: record_timestamps)
end

#inspect

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1290

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)

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# File 'activerecord/lib/active_record/relation.rb', line 1455

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
    model._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 1248

def joined_includes_values
  includes_values & joins_values
end

#limited_count (private)

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# File 'activerecord/lib/active_record/relation.rb', line 1498

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>
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# File 'activerecord/lib/active_record/relation.rb', line 1179

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.

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
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# File 'activerecord/lib/active_record/relation.rb', line 1138

def load_async
  with_connection do |c|
    return load if !c.async_enabled?

    unless loaded?
      result = exec_main_query(async: !c.current_transaction.joinable?)

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

  self
end

#load_records(records) (protected)

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# File 'activerecord/lib/active_record/relation.rb', line 1331

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 71

attr_reader :table, :model, :loaded, :predicate_builder

#locked?

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# File 'activerecord/lib/active_record/relation.rb', line 75

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 125

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
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# File 'activerecord/lib/active_record/relation.rb', line 378

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
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# File 'activerecord/lib/active_record/relation.rb', line 404

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.
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# File 'activerecord/lib/active_record/relation.rb', line 1321

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 1264

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.
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# File 'activerecord/lib/active_record/relation.rb', line 342

def records # :nodoc:
  load
  @records
end

#reload

Forces reloading of relation.

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# File 'activerecord/lib/active_record/relation.rb', line 1189

def reload
  reset
  load
end

#reset

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# File 'activerecord/lib/active_record/relation.rb', line 1194

def reset
  @future_result&.cancel
  @future_result = nil
  @delegate_to_model = 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

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# File 'activerecord/lib/active_record/relation.rb', line 1231

def scope_for_create
  hash = where_clause.to_h(model.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.

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# File 'activerecord/lib/active_record/relation.rb', line 541

def scoping(all_queries: nil, &block)
  registry = model.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.

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# File 'activerecord/lib/active_record/relation.rb', line 353

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

#skip_query_cache_if_necessary(&block) (private)

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# File 'activerecord/lib/active_record/relation.rb', line 1466

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

#tables_in_string(string) (private)

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# File 'activerecord/lib/active_record/relation.rb', line 1491

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

#then(&block)

This method is for internal use only.
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# File 'activerecord/lib/active_record/relation.rb', line 1157

def then(&block) # :nodoc:
  if @future_result
    @future_result.then do
      yield self
    end
  else
    super
  end
end

#to_a

Alias for #to_ary.

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# File 'activerecord/lib/active_record/relation.rb', line 340

alias to_a to_ary

#to_ary Also known as: #to_a

Converts relation objects to ::Array.

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# File 'activerecord/lib/active_record/relation.rb', line 337

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'
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# File 'activerecord/lib/active_record/relation.rb', line 1210

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
    model.with_connection do |conn|
      conn.unprepared_statement { conn.to_sql(arel) }
    end
  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 969

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

#update(id = :all, attributes)

This method is for internal use only.
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# File 'activerecord/lib/active_record/relation.rb', line 621

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

#update!(id = :all, attributes)

This method is for internal use only.
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# File 'activerecord/lib/active_record/relation.rb', line 629

def update!(id = :all, attributes) # :nodoc:
  if id == :all
    each { |record| record.update!(attributes) }
  else
    model.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 588

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

  model.with_connection do |c|
    arel = eager_loading? ? apply_join_dependency.arel : build_arel(c)
    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 model.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)
    c.update(stmt, "#{model} Update All").tap { reset }
  end
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 926

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 = model.touch_attributes_with_time(*names, **options)
    updates.merge!(touch_updates) unless touch_updates.empty?
  end

  update_all updates
end

#upsert(attributes, **kwargs)

Updates or inserts (upserts) a single record into the database in a single SQL INSERT statement. It does not instantiate any models nor does it trigger Active Record callbacks or validations. Though passed values go through Active Record’s type casting and serialization.

See #upsert_all for documentation.

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 800

def upsert(attributes, **kwargs)
  upsert_all([ attributes ], **kwargs)
end

#upsert_all(attributes, on_duplicate: :update, update_only: nil, returning: nil, unique_by: nil, record_timestamps: nil)

Updates or inserts (upserts) multiple records into the database in a single SQL INSERT statement. It does not instantiate any models nor does it trigger Active Record callbacks or validations. Though passed values go through Active Record’s type casting and serialization.

The attributes parameter is an ::Array of Hashes. Every Hash determines the attributes for a single row and must have the same keys.

Returns an Result with its contents based on :returning (see below).

By default, upsert_all will update all the columns that can be updated when there is a conflict. These are all the columns except primary keys, read-only columns, and columns covered by the optional unique_by.

Options

:returning

(PostgreSQL, SQLite3, and MariaDB only) An array of attributes to return for all successfully inserted records, which by default is the primary key. Pass returning: %w[ id name ] for both id and name or returning: false to omit the underlying RETURNING SQL clause entirely.

You can also pass an SQL string if you need more control on the return values (for example, returning: Arel.sql("id, name as new_name")).

:unique_by

(PostgreSQL and SQLite only) By default rows are considered to be unique by every unique index on the table. Any duplicate rows are skipped.

To skip rows according to just one unique index pass :unique_by.

Consider a Book model where no duplicate ISBNs make sense, but if any row has an existing id, or is not unique by another unique index, ActiveRecord::RecordNotUnique is raised.

Unique indexes can be identified by columns or name:

unique_by: :isbn
unique_by: %i[ author_id name ]
unique_by: :index_books_on_isbn

Because it relies on the index information from the database :unique_by is recommended to be paired with Active Record’s schema_cache.

:on_duplicate

Configure the SQL update sentence that will be used in case of conflict.

NOTE: If you use this option you must provide all the columns you want to update by yourself.

Example:

Commodity.upsert_all(
  [
    { id: 2, name: "Copper", price: 4.84 },
    { id: 4, name: "Gold", price: 1380.87 },
    { id: 6, name: "Aluminium", price: 0.35 }
  ],
  on_duplicate: Arel.sql("price = GREATEST(commodities.price, EXCLUDED.price)")
)

See the related :update_only option. Both options can’t be used at the same time.

:update_only

Provide a list of column names that will be updated in case of conflict. If not provided, upsert_all will update all the columns that can be updated. These are all the columns except primary keys, read-only columns, and columns covered by the optional unique_by

Example:

Commodity.upsert_all(
  [
    { id: 2, name: "Copper", price: 4.84 },
    { id: 4, name: "Gold", price: 1380.87 },
    { id: 6, name: "Aluminium", price: 0.35 }
  ],
  update_only: [:price] # Only prices will be updated
)

See the related :on_duplicate option. Both options can’t be used at the same time.

:record_timestamps

By default, automatic setting of timestamp columns is controlled by the model’s record_timestamps config, matching typical behavior.

To override this and force automatic setting of timestamp columns one way or the other, pass :record_timestamps:

record_timestamps: true  # Always set timestamps automatically
record_timestamps: false # Never set timestamps automatically

Examples

# Inserts multiple records, performing an upsert when records have duplicate ISBNs.
# Here "Eloquent Ruby" overwrites "Rework" because its ISBN is duplicate.

Book.upsert_all([
  { title: "Rework", author: "David", isbn: "1" },
  { title: "Eloquent Ruby", author: "Russ", isbn: "1" }
], unique_by: :isbn)

Book.find_by(isbn: "1").title # => "Eloquent Ruby"
[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 910

def upsert_all(attributes, on_duplicate: :update, update_only: nil, returning: nil, unique_by: nil, record_timestamps: nil)
  InsertAll.execute(self, attributes, on_duplicate: on_duplicate, update_only: update_only, returning: returning, unique_by: unique_by, record_timestamps: record_timestamps)
end

#values

[ GitHub ]

  
# File 'activerecord/lib/active_record/relation.rb', line 1282

def values
  @values.dup
end

#values_for_queries

This method is for internal use only.
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# File 'activerecord/lib/active_record/relation.rb', line 1286

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

#where_values_hash(relation_table_name = model.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 1227

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