Class: ActiveRecord::Relation
- Includes:
- Batches, Calculations, Delegation, Explain, FinderMethods, QueryMethods, SpawnMethods, Enumerable
- Defined in:
- activerecord/lib/active_record/relation.rb,
activerecord/lib/active_record/relation/merger.rb,
activerecord/lib/active_record/relation/from_clause.rb,
activerecord/lib/active_record/relation/where_clause.rb,
activerecord/lib/active_record/relation/query_attribute.rb,
activerecord/lib/active_record/relation/record_fetch_warning.rb,
activerecord/lib/active_record/relation/where_clause_factory.rb
Overview
Active Record Relation
Direct Known Subclasses
Defined Under Namespace
Modules: RecordFetchWarning Classes: FromClause, HashMerger, Merger, QueryAttribute, WhereClause, WhereClauseFactory
Constant Summary collapse
- MULTI_VALUE_METHODS =
[:includes, :eager_load, :preload, :select, :group, :order, :joins, :left_outer_joins, :references, :extending, :unscope, :optimizer_hints, :annotate]
- SINGLE_VALUE_METHODS =
[:limit, :offset, :lock, :readonly, :reordering, :reverse_order, :distinct, :create_with, :skip_query_cache]
- CLAUSE_METHODS =
[:where, :having, :from]
- INVALID_METHODS_FOR_DELETE_ALL =
[:distinct, :group, :having]
- VALUE_METHODS =
MULTI_VALUE_METHODS + SINGLE_VALUE_METHODS + CLAUSE_METHODS
Constants included from FinderMethods
Constants included from QueryMethods
QueryMethods::FROZEN_EMPTY_ARRAY, QueryMethods::FROZEN_EMPTY_HASH, QueryMethods::VALID_UNSCOPING_VALUES
Constants included from Batches
Instance Attribute Summary collapse
-
#_deprecated_scope_source ⇒ Object
readonly
:nodoc:.
-
#klass ⇒ Object
(also: #model)
readonly
Returns the value of attribute klass.
-
#loaded ⇒ Object
(also: #loaded?)
readonly
Returns the value of attribute loaded.
-
#predicate_builder ⇒ Object
readonly
Returns the value of attribute predicate_builder.
-
#skip_preloading_value ⇒ Object
Returns the value of attribute skip_preloading_value.
-
#table ⇒ Object
readonly
Returns the value of attribute table.
Instance Method Summary collapse
-
#==(other) ⇒ Object
Compares two relations for equality.
-
#_exec_scope(name, *args, &block) ⇒ Object
:nodoc:.
-
#alias_tracker(joins = [], aliases = nil) ⇒ Object
:nodoc:.
-
#any? ⇒ Boolean
Returns true if there are any records.
-
#arel_attribute(name) ⇒ Object
:nodoc:.
-
#bind_attribute(name, value) {|attr, bind| ... } ⇒ Object
:nodoc:.
-
#blank? ⇒ Boolean
Returns true if relation is blank.
-
#cache_key(timestamp_column = :updated_at) ⇒ Object
Returns a stable cache key that can be used to identify this query.
-
#cache_version(timestamp_column = :updated_at) ⇒ Object
Returns a cache version that can be used together with the cache key to form a recyclable caching scheme.
-
#create(attributes = nil, &block) ⇒ Object
Tries to create a new record with the same scoped attributes defined in the relation.
-
#create!(attributes = nil, &block) ⇒ Object
Similar to #create, but calls create! on the base class.
-
#create_or_find_by(attributes, &block) ⇒ Object
Attempts to create a record with the given attributes in a table that has a unique constraint on one or several of its columns.
-
#create_or_find_by!(attributes, &block) ⇒ Object
Like #create_or_find_by, but calls create! so an exception is raised if the created record is invalid.
-
#delete_all ⇒ Object
Deletes the records without instantiating the records first, and hence not calling the #destroy method nor invoking callbacks.
-
#delete_by(*args) ⇒ Object
Finds and deletes all records matching the specified conditions.
-
#destroy_all ⇒ Object
Destroys the records by instantiating each record and calling its #destroy method.
-
#destroy_by(*args) ⇒ Object
Finds and destroys all records matching the specified conditions.
-
#eager_loading? ⇒ Boolean
Returns true if relation needs eager loading.
-
#empty? ⇒ Boolean
Returns true if there are no records.
-
#empty_scope? ⇒ Boolean
:nodoc:.
-
#encode_with(coder) ⇒ Object
Serializes the relation objects Array.
-
#explain ⇒ Object
Runs EXPLAIN on the query or queries triggered by this relation and returns the result as a string.
-
#find_or_create_by(attributes, &block) ⇒ Object
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) ⇒ Object
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) ⇒ Object
-
#first_or_create(attributes = nil, &block) ⇒ Object
:nodoc:.
-
#first_or_create!(attributes = nil, &block) ⇒ Object
:nodoc:.
-
#first_or_initialize(attributes = nil, &block) ⇒ Object
:nodoc:.
-
#has_limit_or_offset? ⇒ Boolean
:nodoc:.
-
#initialize(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {}) ⇒ Relation
constructor
A new instance of Relation.
- #initialize_copy(other) ⇒ Object
- #inspect ⇒ Object
-
#joined_includes_values ⇒ Object
Joins that are also marked for preloading.
-
#load(&block) ⇒ Object
Causes the records to be loaded from the database if they have not been loaded already.
-
#many? ⇒ Boolean
Returns true if there is more than one record.
-
#new(attributes = nil, &block) ⇒ Object
(also: #build)
Initializes new record from relation while maintaining the current scope.
-
#none? ⇒ Boolean
Returns true if there are no records.
-
#one? ⇒ Boolean
Returns true if there is exactly one record.
-
#preload_associations(records) ⇒ Object
:nodoc:.
- #pretty_print(q) ⇒ Object
-
#records ⇒ Object
:nodoc:.
-
#reload ⇒ Object
Forces reloading of relation.
- #reset ⇒ Object
- #scope_for_create ⇒ Object
-
#scoping ⇒ Object
Scope all queries to the current scope.
-
#size ⇒ Object
Returns size of the records.
-
#to_ary ⇒ Object
(also: #to_a)
Converts relation objects to Array.
-
#to_sql ⇒ Object
Returns sql statement for the relation.
-
#touch_all(*names, time: nil) ⇒ Object
Touches all records in the current relation without instantiating records first with the
updated_at
/updated_on
attributes set to the current time or the time specified. -
#update(id = :all, attributes) ⇒ Object
:nodoc:.
-
#update_all(updates) ⇒ Object
Updates all records in the current relation with details given.
-
#update_counters(counters) ⇒ Object
Updates the counters of the records in the current relation.
- #values ⇒ Object
-
#where_values_hash(relation_table_name = klass.table_name) ⇒ Object
Returns a hash of where conditions.
Methods included from FinderMethods
#exists?, #fifth, #fifth!, #find, #find_by, #find_by!, #first, #first!, #forty_two, #forty_two!, #fourth, #fourth!, #last, #last!, #raise_record_not_found_exception!, #second, #second!, #second_to_last, #second_to_last!, #take, #take!, #third, #third!, #third_to_last, #third_to_last!
Methods included from Calculations
#average, #calculate, #count, #ids, #maximum, #minimum, #pick, #pluck, #sum
Methods included from SpawnMethods
#except, #merge, #merge!, #only, #spawn
Methods included from QueryMethods
#_select!, #annotate, #annotate!, #arel, #construct_join_dependency, #create_with, #create_with!, #distinct, #distinct!, #eager_load, #eager_load!, #extending, #extending!, #extract_associated, #from, #from!, #group, #group!, #having, #having!, #includes, #includes!, #joins, #joins!, #left_outer_joins, #left_outer_joins!, #limit, #limit!, #lock, #lock!, #none, #none!, #offset, #offset!, #optimizer_hints, #optimizer_hints!, #or, #or!, #order, #order!, #preload, #preload!, #readonly, #readonly!, #references, #references!, #reorder, #reorder!, #reselect, #reselect!, #reverse_order, #reverse_order!, #rewhere, #select, #skip_preloading!, #skip_query_cache!, #unscope, #unscope!, #where, #where!
Methods included from ActiveSupport::Concern
#append_features, #class_methods, extended, #included
Methods included from Batches
#find_each, #find_in_batches, #in_batches
Methods included from Explain
#collecting_queries_for_explain, #exec_explain
Methods included from Enumerable
#as_json, #compact_blank, #exclude?, #excluding, #including, #index_by, #index_with, #pluck, #sum, #without
Constructor Details
#initialize(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {}) ⇒ Relation
Returns a new instance of Relation.
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# File 'activerecord/lib/active_record/relation.rb', line 27 def initialize(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {}) @klass = klass @table = table @values = values @offsets = {} @loaded = false @predicate_builder = predicate_builder @delegate_to_klass = false end |
Instance Attribute Details
#_deprecated_scope_source ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 755 def _deprecated_scope_source @_deprecated_scope_source end |
#klass ⇒ Object (readonly) Also known as: model
Returns the value of attribute klass
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# File 'activerecord/lib/active_record/relation.rb', line 21 def klass @klass end |
#loaded ⇒ Object (readonly) Also known as: loaded?
Returns the value of attribute loaded
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# File 'activerecord/lib/active_record/relation.rb', line 21 def loaded @loaded end |
#predicate_builder ⇒ Object (readonly)
Returns the value of attribute predicate_builder
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# File 'activerecord/lib/active_record/relation.rb', line 21 def predicate_builder @predicate_builder end |
#skip_preloading_value ⇒ Object
Returns the value of attribute skip_preloading_value
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# File 'activerecord/lib/active_record/relation.rb', line 22 def skip_preloading_value @skip_preloading_value end |
#table ⇒ Object (readonly)
Returns the value of attribute table
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# File 'activerecord/lib/active_record/relation.rb', line 21 def table @table end |
Instance Method Details
#==(other) ⇒ Object
Compares two relations for equality.
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# File 'activerecord/lib/active_record/relation.rb', line 699 def ==(other) case other when Associations::CollectionProxy, AssociationRelation self == other.records when Relation other.to_sql == to_sql when Array records == other end end |
#_exec_scope(name, *args, &block) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 401 def _exec_scope(name, *args, &block) # :nodoc: @delegate_to_klass = true _scoping(_deprecated_spawn(name)) { instance_exec(*args, &block) || self } ensure @delegate_to_klass = false end |
#alias_tracker(joins = [], aliases = nil) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 740 def alias_tracker(joins = [], aliases = nil) # :nodoc: joins += [aliases] if aliases ActiveRecord::Associations::AliasTracker.create(connection, table.name, joins) end |
#any? ⇒ Boolean
Returns true if there are any records.
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# File 'activerecord/lib/active_record/relation.rb', line 277 def any? return super if block_given? !empty? end |
#arel_attribute(name) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 42 def arel_attribute(name) # :nodoc: klass.arel_attribute(name, table) end |
#bind_attribute(name, value) {|attr, bind| ... } ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 46 def bind_attribute(name, value) # :nodoc: if reflection = klass._reflect_on_association(name) name = reflection.foreign_key value = value.read_attribute(reflection.klass.primary_key) unless value.nil? end attr = arel_attribute(name) bind = predicate_builder.build_bind_attribute(attr.name, value) yield attr, bind end |
#blank? ⇒ Boolean
Returns true if relation is blank.
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# File 'activerecord/lib/active_record/relation.rb', line 715 def blank? records.blank? end |
#cache_key(timestamp_column = :updated_at) ⇒ Object
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 ActiveRecord::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)
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# File 'activerecord/lib/active_record/relation.rb', line 311 def cache_key( = :updated_at) @cache_keys ||= {} @cache_keys[] ||= klass.collection_cache_key(self, ) end |
#cache_version(timestamp_column = :updated_at) ⇒ Object
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%')
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# File 'activerecord/lib/active_record/relation.rb', line 338 def cache_version( = :updated_at) if collection_cache_versioning @cache_versions ||= {} @cache_versions[] ||= compute_cache_version() end end |
#create(attributes = nil, &block) ⇒ Object
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, ...>
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# File 'activerecord/lib/active_record/relation.rb', line 95 def create(attributes = nil, &block) if attributes.is_a?(Array) attributes.collect { |attr| create(attr, &block) } else block = _deprecated_scope_block("create", &block) scoping { klass.create(attributes, &block) } end end |
#create!(attributes = nil, &block) ⇒ Object
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!.
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# File 'activerecord/lib/active_record/relation.rb', line 110 def create!(attributes = nil, &block) if attributes.is_a?(Array) attributes.collect { |attr| create!(attr, &block) } else block = _deprecated_scope_block("create!", &block) scoping { klass.create!(attributes, &block) } end end |
#create_or_find_by(attributes, &block) ⇒ Object
Attempts to create a record with the given attributes in a table that has a unique 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 avoids the problem of stale reads between the SELECT and the INSERT, as that method needs to first query the table, then attempt to insert a row if none is found.
There are several drawbacks to #create_or_find_by, though:
-
The underlying table must have the relevant columns defined with unique constraints.
-
A unique constraint violation may be triggered by only one, or at least less than all, of the given attributes. This means that the subsequent #find_by! may fail to find a matching record, which will then raise an
ActiveRecord::RecordNotFound
exception, rather than a record with the given attributes. -
While we avoid the race condition between SELECT -> INSERT from #find_or_create_by, we actually have another race condition between INSERT -> SELECT, which can be triggered if a DELETE between those two statements is run by another client. But for most applications, that’s a significantly less likely condition to hit.
-
It relies on exception handling to handle control flow, which may be marginally slower.
-
The primary key may auto-increment on each create, even if it fails. This can accelerate the problem of running out of integers, if the underlying table is still stuck on a primary key of type int (note: All Rails apps since 5.1+ have defaulted to bigint, which is not liable to this problem).
This method will return a record if all given attributes are covered by unique constraints (unless the INSERT -> DELETE -> SELECT race condition is triggered), but if creation was attempted and failed due to validation errors it won’t be persisted, you get what #create returns in such situation.
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# File 'activerecord/lib/active_record/relation.rb', line 209 def create_or_find_by(attributes, &block) transaction(requires_new: true) { create(attributes, &block) } rescue ActiveRecord::RecordNotUnique find_by!(attributes) end |
#create_or_find_by!(attributes, &block) ⇒ Object
Like #create_or_find_by, but calls create! so an exception is raised if the created record is invalid.
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# File 'activerecord/lib/active_record/relation.rb', line 218 def create_or_find_by!(attributes, &block) transaction(requires_new: true) { create!(attributes, &block) } rescue ActiveRecord::RecordNotUnique find_by!(attributes) end |
#delete_all ⇒ Object
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
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# File 'activerecord/lib/active_record/relation.rb', line 568 def delete_all 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 if eager_loading? relation = apply_join_dependency return relation.delete_all end stmt = Arel::DeleteManager.new stmt.from(arel.join_sources.empty? ? table : arel.source) stmt.key = arel_attribute(primary_key) stmt.take(arel.limit) stmt.offset(arel.offset) stmt.order(*arel.orders) stmt.wheres = arel.constraints affected = @klass.connection.delete(stmt, "#{@klass} Destroy") reset affected end |
#delete_by(*args) ⇒ Object
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)
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# File 'activerecord/lib/active_record/relation.rb', line 618 def delete_by(*args) where(*args).delete_all end |
#destroy_all ⇒ Object
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 546 def destroy_all records.each(&:destroy).tap { reset } end |
#destroy_by(*args) ⇒ Object
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)
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# File 'activerecord/lib/active_record/relation.rb', line 605 def destroy_by(*args) where(*args).destroy_all end |
#eager_loading? ⇒ Boolean
Returns true if relation needs eager loading.
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# File 'activerecord/lib/active_record/relation.rb', line 684 def eager_loading? @should_eager_load ||= eager_load_values.any? || includes_values.any? && (joined_includes_values.any? || references_eager_loaded_tables?) end |
#empty? ⇒ Boolean
Returns true if there are no records.
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# File 'activerecord/lib/active_record/relation.rb', line 265 def empty? return @records.empty? if loaded? !exists? end |
#empty_scope? ⇒ Boolean
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 732 def empty_scope? # :nodoc: @values == klass.unscoped.values end |
#encode_with(coder) ⇒ Object
Serializes the relation objects Array.
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# File 'activerecord/lib/active_record/relation.rb', line 255 def encode_with(coder) coder.represent_seq(nil, records) end |
#explain ⇒ Object
Runs EXPLAIN on the query or queries triggered by this relation and returns the result as a string. The string is formatted imitating the ones printed by the database shell.
Note that this method actually runs the queries, since the results of some are needed by the next ones when eager loading is going on.
Please see further details in the Active Record Query Interface guide.
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# File 'activerecord/lib/active_record/relation.rb', line 239 def explain exec_explain(collecting_queries_for_explain { exec_queries }) end |
#find_or_create_by(attributes, &block) ⇒ Object
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
# different 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.
Please note this method is not atomic, it runs first a SELECT, and if there are no results an INSERT is attempted. If there are other threads or processes there is a race condition between both calls and it could be the case that you end up with two similar records.
If this might be a problem for your application, please see #create_or_find_by.
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# File 'activerecord/lib/active_record/relation.rb', line 168 def find_or_create_by(attributes, &block) find_by(attributes) || create(attributes, &block) end |
#find_or_create_by!(attributes, &block) ⇒ Object
Like #find_or_create_by, but calls create! so an exception is raised if the created record is invalid.
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# File 'activerecord/lib/active_record/relation.rb', line 175 def find_or_create_by!(attributes, &block) find_by(attributes) || create!(attributes, &block) end |
#find_or_initialize_by(attributes, &block) ⇒ Object
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# File 'activerecord/lib/active_record/relation.rb', line 226 def find_or_initialize_by(attributes, &block) find_by(attributes) || new(attributes, &block) end |
#first_or_create(attributes = nil, &block) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 119 def first_or_create(attributes = nil, &block) # :nodoc: first || create(attributes, &block) end |
#first_or_create!(attributes = nil, &block) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 123 def first_or_create!(attributes = nil, &block) # :nodoc: first || create!(attributes, &block) end |
#first_or_initialize(attributes = nil, &block) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 127 def first_or_initialize(attributes = nil, &block) # :nodoc: first || new(attributes, &block) end |
#has_limit_or_offset? ⇒ Boolean
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 736 def has_limit_or_offset? # :nodoc: limit_value || offset_value end |
#initialize_copy(other) ⇒ Object
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# File 'activerecord/lib/active_record/relation.rb', line 37 def initialize_copy(other) @values = @values.dup reset end |
#inspect ⇒ Object
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# File 'activerecord/lib/active_record/relation.rb', line 723 def inspect subject = loaded? ? records : self entries = subject.take([limit_value, 11].compact.min).map!(&:inspect) entries[10] = "..." if entries.size == 11 "#<#{self.class.name} [#{entries.join(', ')}]>" end |
#joined_includes_values ⇒ Object
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] }
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# File 'activerecord/lib/active_record/relation.rb', line 694 def joined_includes_values includes_values & joins_values end |
#load(&block) ⇒ Object
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 628 def load(&block) unless loaded? @records = exec_queries(&block) @loaded = true end self end |
#many? ⇒ Boolean
Returns true if there is more than one record.
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# File 'activerecord/lib/active_record/relation.rb', line 289 def many? return super if block_given? limit_value ? records.many? : size > 1 end |
#new(attributes = nil, &block) ⇒ Object 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
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# File 'activerecord/lib/active_record/relation.rb', line 69 def new(attributes = nil, &block) block = _deprecated_scope_block("new", &block) scoping { klass.new(attributes, &block) } end |
#none? ⇒ Boolean
Returns true if there are no records.
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# File 'activerecord/lib/active_record/relation.rb', line 271 def none? return super if block_given? empty? end |
#one? ⇒ Boolean
Returns true if there is exactly one record.
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# File 'activerecord/lib/active_record/relation.rb', line 283 def one? return super if block_given? limit_value ? records.one? : size == 1 end |
#preload_associations(records) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 745 def preload_associations(records) # :nodoc: preload = preload_values preload += includes_values unless eager_loading? preloader = nil preload.each do |associations| preloader ||= build_preloader preloader.preload records, associations end end |
#pretty_print(q) ⇒ Object
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# File 'activerecord/lib/active_record/relation.rb', line 710 def pretty_print(q) q.pp(records) end |
#records ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 249 def records # :nodoc: load @records end |
#reload ⇒ Object
Forces reloading of relation.
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# File 'activerecord/lib/active_record/relation.rb', line 638 def reload reset load end |
#reset ⇒ Object
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# File 'activerecord/lib/active_record/relation.rb', line 643 def reset @delegate_to_klass = false @_deprecated_scope_source = nil @to_sql = @arel = @loaded = @should_eager_load = nil @records = [].freeze @offsets = {} @take = nil self end |
#scope_for_create ⇒ Object
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# File 'activerecord/lib/active_record/relation.rb', line 679 def scope_for_create where_values_hash.merge!(create_with_value.stringify_keys) end |
#scoping ⇒ Object
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
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 397 def scoping already_in_scope? ? yield : _scoping(self) { yield } end |
#size ⇒ Object
Returns size of the records.
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# File 'activerecord/lib/active_record/relation.rb', line 260 def size loaded? ? @records.length : count(:all) end |
#to_ary ⇒ Object Also known as: to_a
Converts relation objects to Array.
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# File 'activerecord/lib/active_record/relation.rb', line 244 def to_ary records.dup end |
#to_sql ⇒ Object
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 657 def to_sql @to_sql ||= begin if eager_loading? apply_join_dependency do |relation, join_dependency| relation = join_dependency.apply_column_aliases(relation) relation.to_sql end else conn = klass.connection conn.unprepared_statement { conn.to_sql(arel) } end end end |
#touch_all(*names, time: nil) ⇒ Object
Touches all records in the current relation without instantiating records first with the updated_at
/updated_on
attributes set to the current time or the time specified. 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'"
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# File 'activerecord/lib/active_record/relation.rb', line 526 def touch_all(*names, time: nil) update_all klass.touch_attributes_with_time(*names, time: time) end |
#update(id = :all, attributes) ⇒ Object
:nodoc:
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# File 'activerecord/lib/active_record/relation.rb', line 463 def update(id = :all, attributes) # :nodoc: if id == :all each { |record| record.update(attributes) } else klass.update(id, attributes) end end |
#update_all(updates) ⇒ Object
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.
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.
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')
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# File 'activerecord/lib/active_record/relation.rb', line 432 def update_all(updates) raise ArgumentError, "Empty list of attributes to change" if updates.blank? if eager_loading? relation = apply_join_dependency return relation.update_all(updates) end stmt = Arel::UpdateManager.new stmt.table(arel.join_sources.empty? ? table : arel.source) stmt.key = arel_attribute(primary_key) stmt.take(arel.limit) stmt.offset(arel.offset) stmt.order(*arel.orders) stmt.wheres = arel.constraints if updates.is_a?(Hash) if klass.locking_enabled? && !updates.key?(klass.locking_column) && !updates.key?(klass.locking_column.to_sym) attr = arel_attribute(klass.locking_column) updates[attr.name] = _increment_attribute(attr) end stmt.set _substitute_values(updates) else stmt.set Arel.sql(klass.sanitize_sql_for_assignment(updates, table.name)) end @klass.connection.update stmt, "#{@klass} Update All" end |
#update_counters(counters) ⇒ Object
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)
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# File 'activerecord/lib/active_record/relation.rb', line 483 def update_counters(counters) touch = counters.delete(:touch) updates = {} counters.each do |counter_name, value| attr = arel_attribute(counter_name) updates[attr.name] = _increment_attribute(attr, value) end if touch names = touch if touch != true names = Array(names) = names. touch_updates = klass.touch_attributes_with_time(*names, **) updates.merge!(touch_updates) unless touch_updates.empty? end update_all updates end |
#values ⇒ Object
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# File 'activerecord/lib/active_record/relation.rb', line 719 def values @values.dup end |
#where_values_hash(relation_table_name = klass.table_name) ⇒ Object
Returns a hash of where conditions.
User.where(name: 'Oscar').where_values_hash
# => {name: "Oscar"}
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# File 'activerecord/lib/active_record/relation.rb', line 675 def where_values_hash(relation_table_name = klass.table_name) where_clause.to_h(relation_table_name) end |