Class: ActiveRecord::Relation
Relationships & Source Files | |
Namespace Children | |
Classes:
| |
Extension / Inclusion / Inheritance Descendants | |
Subclasses:
|
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Super Chains via Extension / Inclusion / Inheritance | |
Instance Chain:
|
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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/where_clause.rb |
Constant Summary
-
CLAUSE_METHODS =
# File 'activerecord/lib/active_record/relation.rb', line 62[:where, :having, :from]
-
INVALID_METHODS_FOR_DELETE_ALL =
# File 'activerecord/lib/active_record/relation.rb', line 63[:distinct, :with, :with_recursive]
-
MULTI_VALUE_METHODS =
# File 'activerecord/lib/active_record/relation.rb', line 54[: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 59[: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 65MULTI_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
FinderMethods
- Included
Class Method Summary
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
readonly
Alias for #model.
-
#loaded?
readonly
Alias for #loaded.
-
#many? ⇒ Boolean
readonly
Returns true if there is more than one record.
- #model (also: #klass) readonly
- #predicate_builder readonly
- #readonly? ⇒ Boolean 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
QueryMethods
- Included
Delegation
- Included
::Enumerable
- Included
#many? | Returns |
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)
-
#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(id_or_array)
Deletes the row with a primary key matching the
id
argument, using an SQLDELETE
statement, and returns the number of rows deleted. -
#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(id)
Destroy an object (or multiple objects) that has the given id.
-
#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)
-
#insert(attributes, returning: nil, unique_by: nil, record_timestamps: nil)
Inserts a single record into the database in a single SQL INSERT statement.
-
#insert!(attributes, returning: nil, record_timestamps: nil)
Inserts a single record into the database in a single SQL INSERT statement.
-
#insert_all(attributes, returning: nil, unique_by: nil, record_timestamps: nil)
Inserts multiple records into the database in a single SQL INSERT statement.
-
#insert_all!(attributes, returning: nil, record_timestamps: nil)
Inserts multiple records into the database in a single SQL INSERT statement.
- #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.
-
#upsert(attributes, **kwargs)
Updates or inserts (upserts) a single record into the database in a single SQL INSERT statement.
-
#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.
- #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
- #then(&block) 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 = model.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
SignedId::RelationMethods
- Included
TokenFor::RelationMethods
- Included
#find_by_token_for | Finds a record using a given |
#find_by_token_for! | Finds a record using a given |
FinderMethods
- Included
#exists? | Returns true if a record exists in the table that matches the |
#fifth | Find the fifth record. |
#fifth! | Same as |
#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_sole_by | Finds the sole matching record. |
#first | Find the first record (or first N records if a parameter is supplied). |
#first! | Same as |
#forty_two | Find the forty-second record. |
#forty_two! | Same as |
#fourth | Find the fourth record. |
#fourth! | Same as |
#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 |
#member? | Alias for FinderMethods#include?. |
#second | Find the second record. |
#second! | Same as |
#second_to_last | Find the second-to-last record. |
#second_to_last! | Same as |
#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 |
#third | Find the third record. |
#third! | Same as |
#third_to_last | Find the third-to-last record. |
#third_to_last! | Same as |
#_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 |
Calculations
- Included
#async_average | Same as |
#async_count | Same as |
#async_ids | Same as |
#async_maximum | Same as |
#async_minimum | Same as |
#async_pick | Same as |
#async_pluck | Same as |
#async_sum | Same as |
#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 |
#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 |
#merge | Merges in the conditions from |
#only | Removes any condition from the query other than the one(s) specified in |
#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 |
#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 |
#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 |
#includes | Specify associations |
#invert_where | Allows you to invert an entire where clause instead of manually applying conditions. |
#joins | Performs JOINs on |
#left_joins | Alias for QueryMethods#left_outer_joins. |
#left_outer_joins | Performs LEFT OUTER JOINs on |
#limit | Specifies a limit for the number of records to retrieve. |
#lock | Specifies locking settings (default to |
#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 |
#preload | Specify associations |
#readonly | Mark a relation as readonly. |
#references | Use to indicate that the given |
#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 |
#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 | Alias for QueryMethods#excluding. |
#arel_columns, #async!, | |
#build_having_clause | Alias for QueryMethods#build_where_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 |
#arel | Returns the |
#construct_join_dependency, #create_with!, | |
#distinct! | Like |
#eager_load!, #excluding!, #extending!, #from!, #group!, #having!, #includes!, #invert_where!, #joins!, #left_outer_joins!, #limit!, #lock!, #none!, #offset!, #optimizer_hints!, #or!, | |
#order! | Same as |
#preload!, #readonly!, #references!, | |
#regroup! | Same as |
#reorder! | Same as |
#reselect! | Same as |
#reverse_order!, #skip_preloading!, #skip_query_cache!, #strict_loading!, #unscope!, #where!, | |
#with! | Like |
#with_recursive! | Like |
#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 |
#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 |
#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
#&, #+, #-, #[], #as_json, #intersect?, #to_formatted_s, #to_fs, #to_sentence, #to_xml, #|, #respond_to_missing? |
::Enumerable
- Included
#compact_blank | Returns a new |
#exclude? | The negative of the |
#excluding | Returns a copy of the enumerable excluding the specified elements. |
#in_order_of | Returns a new |
#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
Constructor Details
.new(model, table: nil, predicate_builder: nil, values: {}) ⇒ Relation
# 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.
# 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.
# 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.
#empty_scope? ⇒ Boolean
(readonly)
#has_limit_or_offset? ⇒ Boolean
(readonly)
# 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.
# File 'activerecord/lib/active_record/relation.rb', line 73
alias :klass :model
#loaded? (readonly)
Alias for #loaded.
# File 'activerecord/lib/active_record/relation.rb', line 74
alias :loaded? :loaded
#many? ⇒ Boolean
(readonly)
Returns true if there is more than one record.
# 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 ]
#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.
# 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.
# 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 ]#_create!(attributes, &block) (private)
[ GitHub ]#_exec_scope
#_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 ]#_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)
# 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)
# 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
# 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| ... }
# 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.
# 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)
# File 'activerecord/lib/active_record/relation.rb', line 438
def cache_key( = "updated_at") @cache_keys ||= {} @cache_keys[ ] ||= model.collection_cache_key(self, ) end
#cache_key_with_version
Returns a cache key along with the version.
# 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%')
# File 'activerecord/lib/active_record/relation.rb', line 465
def cache_version( = :updated_at) if model.collection_cache_versioning @cache_versions ||= {} @cache_versions[ ] ||= compute_cache_version( ) end end
#compute_cache_key(timestamp_column = :updated_at) (private)
# File 'activerecord/lib/active_record/relation.rb', line 443
def compute_cache_key( = :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( )}" end end
#compute_cache_version(timestamp_column) (private)
# File 'activerecord/lib/active_record/relation.rb', line 472
def compute_cache_version( ) # :nodoc: = .to_s if loaded? size = records.size if size > 0 = records.map { |record| record.read_attribute( ) }.max end else collection = eager_loading? ? apply_join_dependency : self with_connection do |c| column = c.visitor.compile(table[ ]) 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, = c.select_rows(arel, nil).first if size column_type = model.type_for_attribute( ) = column_type.deserialize( ) else size = 0 end end end if "#{size}-#{ .utc.to_fs(model. )}" 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, ...>
# 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!}.
# 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.
# 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.
# 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)
[ GitHub ]#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 id
s.
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])
# 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
# 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)
# 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)
#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
#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)
# 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
.
# 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)
[ GitHub ]# 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)
[ GitHub ]# 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.
# File 'activerecord/lib/active_record/relation.rb', line 332
def explain(* ) ExplainProxy.new(self, ) 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.
# 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.
# 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.
# 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)
# 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)
# 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)
# 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)
# File 'activerecord/lib/active_record/relation.rb', line 1341
def global_scope?(registry) registry.global_current_scope(model, true) end
#initialize_copy(other)
[ GitHub ]# 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.
# 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: ) 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.
# File 'activerecord/lib/active_record/relation.rb', line 733
def insert!(attributes, returning: nil, record_timestamps: nil) insert_all!([ attributes ], returning: returning, 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 orreturning: false
to omit the underlyingRETURNING
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
:: true # Always set timestamps automatically : 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.
.books.create_with(created_at: Time.now).insert_all([
{ id: 1, title: "Rework" },
{ id: 2, title: "Eloquent Ruby" }
])
#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 orreturning: false
to omit the underlyingRETURNING
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
:: true # Always set timestamps automatically : 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" }
])
#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)
[ GitHub ]# 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] }
# File 'activerecord/lib/active_record/relation.rb', line 1248
def joined_includes_values includes_values & joins_values end
#limited_count (private)
[ GitHub ]# 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>
# 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
# 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)
[ GitHub ]#loaded (readonly) Also known as: #loaded?
[ GitHub ]# File 'activerecord/lib/active_record/relation.rb', line 71
attr_reader :table, :model, :loaded, :predicate_builder
#locked?
[ GitHub ]# 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
# 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
# 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
# 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)
# 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 ]#records
# File 'activerecord/lib/active_record/relation.rb', line 342
def records # :nodoc: load @records end
#reload
Forces reloading of relation.
#reset
[ GitHub ]# 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
[ GitHub ]#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.
# 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.
#skip_query_cache_if_necessary(&block) (private)
[ GitHub ]# 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)
[ GitHub ]# 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)
# 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.
# 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
.
# 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'
# 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'"
# 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)
# 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)
# 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'"))
# 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: .id).update_counters(comment_count: 1)
# 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) = names. touch_updates = model.touch_attributes_with_time(*names, ** ) 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.
# 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 orreturning: false
to omit the underlyingRETURNING
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 optionalunique_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
:: true # Always set timestamps automatically : 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"
# 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: ) end
#values
[ GitHub ]# File 'activerecord/lib/active_record/relation.rb', line 1282
def values @values.dup end
#values_for_queries
# 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)
Returns a hash of where conditions.
User.where(name: 'Oscar').where_values_hash
# => {name: "Oscar"}
# 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