diff options
Diffstat (limited to 'activerecord/lib/active_record/relation.rb')
| -rw-r--r-- | activerecord/lib/active_record/relation.rb | 242 |
1 files changed, 204 insertions, 38 deletions
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb index d5b6082d13..ea8f44752b 100644 --- a/activerecord/lib/active_record/relation.rb +++ b/activerecord/lib/active_record/relation.rb @@ -5,7 +5,7 @@ module ActiveRecord class Relation MULTI_VALUE_METHODS = [:includes, :eager_load, :preload, :select, :group, :order, :joins, :left_outer_joins, :references, - :extending, :unscope] + :extending, :unscope, :optimizer_hints, :annotate] SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :reordering, :reverse_order, :distinct, :create_with, :skip_query_cache] @@ -44,6 +44,11 @@ module ActiveRecord end 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 @@ -62,6 +67,7 @@ module ActiveRecord # user = users.new { |user| user.name = 'Oscar' } # user.name # => Oscar def new(attributes = nil, &block) + block = _deprecated_scope_block("new", &block) scoping { klass.new(attributes, &block) } end @@ -87,7 +93,12 @@ module ActiveRecord # users.create(name: nil) # validation on name # # => #<User id: nil, name: nil, ...> def create(attributes = nil, &block) - scoping { klass.create(attributes, &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 # Similar to #create, but calls @@ -97,7 +108,12 @@ module ActiveRecord # Expects arguments in the same format as # {ActiveRecord::Base.create!}[rdoc-ref:Persistence::ClassMethods#create!]. def create!(attributes = nil, &block) - scoping { klass.create!(attributes, &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 def first_or_create(attributes = nil, &block) # :nodoc: @@ -163,7 +179,7 @@ module ActiveRecord # 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. + # 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 @@ -173,7 +189,7 @@ module ActiveRecord # # * 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 + # of the given attributes. This means that the subsequent #find_by! may fail to find a # matching record, which will then raise an <tt>ActiveRecord::RecordNotFound</tt> exception, # rather than a record with the given attributes. # * While we avoid the race condition between SELECT -> INSERT from #find_or_create_by, @@ -181,6 +197,10 @@ module ActiveRecord # 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 @@ -271,32 +291,100 @@ module ActiveRecord limit_value ? records.many? : size > 1 end - # Returns a cache key that can be used to identify the records fetched by - # this query. The cache key is built with a fingerprint of the sql query, - # the number of records matched by the query and a 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 key changes. + # 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-1850ab3d302391b85b8693e941286659-1-20150714212553907087000" + # Product.where("name like ?", "%Cosmic Encounter%").cache_key + # # => "products/query-1850ab3d302391b85b8693e941286659" # - # If the collection is loaded, the method will iterate through the records - # to generate the timestamp, otherwise it will trigger one SQL query like: + # 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. # - # SELECT COUNT(*), MAX("products"."updated_at") FROM "products" WHERE (name like '%Cosmic Encounter%') + # 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) - # - # You can customize the strategy to generate the key on a per model basis - # overriding ActiveRecord::Base#collection_cache_key. def cache_key(timestamp_column = :updated_at) @cache_keys ||= {} - @cache_keys[timestamp_column] ||= @klass.collection_cache_key(self, timestamp_column) + @cache_keys[timestamp_column] ||= klass.collection_cache_key(self, timestamp_column) end + def compute_cache_key(timestamp_column = :updated_at) # :nodoc: + query_signature = ActiveSupport::Digest.hexdigest(to_sql) + key = "#{klass.model_name.cache_key}/query-#{query_signature}" + + if cache_version(timestamp_column) + key + else + "#{key}-#{compute_cache_version(timestamp_column)}" + end + end + private :compute_cache_key + + # 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%') + def cache_version(timestamp_column = :updated_at) + if collection_cache_versioning + @cache_versions ||= {} + @cache_versions[timestamp_column] ||= compute_cache_version(timestamp_column) + end + end + + def compute_cache_version(timestamp_column) # :nodoc: + if loaded? || distinct_value + size = records.size + if size > 0 + timestamp = max_by(×tamp_column)._read_attribute(timestamp_column) + end + else + collection = eager_loading? ? apply_join_dependency : self + + column = connection.visitor.compile(arel_attribute(timestamp_column)) + select_values = "COUNT(*) AS #{connection.quote_column_name("size")}, MAX(%s) AS timestamp" + + if collection.has_limit_or_offset? + query = collection.select("#{column} AS collection_cache_key_timestamp") + 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 + + result = connection.select_one(arel, nil) + + if result + column_type = klass.type_for_attribute(timestamp_column) + timestamp = column_type.deserialize(result["timestamp"]) + size = result["size"] + else + timestamp = nil + size = 0 + end + end + + if timestamp + "#{size}-#{timestamp.utc.to_s(cache_timestamp_format)}" + else + "#{size}" + end + end + private :compute_cache_version + # Scope all queries to the current scope. # # Comment.where(post_id: 1).scoping do @@ -307,12 +395,12 @@ module ActiveRecord # Please check unscoped if you want to remove all previous scopes (including # the default_scope) during the execution of a block. def scoping - @delegate_to_klass ? yield : klass._scoping(self) { yield } + already_in_scope? ? yield : _scoping(self) { yield } end - def _exec_scope(*args, &block) # :nodoc: + def _exec_scope(name, *args, &block) # :nodoc: @delegate_to_klass = true - instance_exec(*args, &block) || self + _scoping(_deprecated_spawn(name)) { instance_exec(*args, &block) || self } ensure @delegate_to_klass = false end @@ -322,6 +410,8 @@ module ActiveRecord # 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. @@ -356,6 +446,12 @@ module ActiveRecord 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)) @@ -372,16 +468,25 @@ module ActiveRecord end end - def update_counters(counters) # :nodoc: + # 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. + # * <tt>:touch</tt> option - Touch the timestamp columns when updating. + # * If attributes names are passed, they are updated along with update_at/on attributes. + # + # === Examples + # + # # For Posts by a given author increment the comment_count by 1. + # Post.where(author_id: author.id).update_counters(comment_count: 1) + def update_counters(counters) touch = counters.delete(:touch) updates = {} counters.each do |counter_name, value| attr = arel_attribute(counter_name) - bind = predicate_builder.build_bind_attribute(attr.name, value.abs) - expr = table.coalesce(Arel::Nodes::UnqualifiedColumn.new(attr), 0) - expr = value < 0 ? expr - bind : expr + bind - updates[counter_name] = expr.expr + updates[attr.name] = _increment_attribute(attr, value) end if touch @@ -393,10 +498,10 @@ module ActiveRecord update_all updates end - # Touches all records in the current relation without instantiating records first with the updated_at/on attributes + # 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/on attributes. + # 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 @@ -417,12 +522,7 @@ module ActiveRecord # Person.where(name: 'David').touch_all # # => "UPDATE \"people\" SET \"updated_at\" = '2018-01-04 22:55:23.132670' WHERE \"people\".\"name\" = 'David'" def touch_all(*names, time: nil) - if klass.locking_enabled? - names << { time: time } - update_counters(klass.locking_column => 1, touch: names) - else - update_all klass.touch_attributes_with_time(*names, time: time) - end + update_all klass.touch_attributes_with_time(*names, time: time) end # Destroys the records by instantiating each @@ -465,8 +565,8 @@ module ActiveRecord # # => ActiveRecord::ActiveRecordError: delete_all doesn't support distinct def delete_all invalid_methods = INVALID_METHODS_FOR_DELETE_ALL.select do |method| - value = get_value(method) - SINGLE_VALUE_METHODS.include?(method) ? value : value.any? + value = @values[method] + method == :distinct ? value : value&.any? end if invalid_methods.any? raise ActiveRecordError.new("delete_all doesn't support #{invalid_methods.join(', ')}") @@ -491,6 +591,32 @@ module ActiveRecord affected end + # Finds and destroys all records matching the specified conditions. + # This is short-hand for <tt>relation.where(condition).destroy_all</tt>. + # 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) + def destroy_by(*args) + where(*args).destroy_all + end + + # Finds and deletes all records matching the specified conditions. + # This is short-hand for <tt>relation.where(condition).delete_all</tt>. + # Returns the number of rows affected. + # + # If no record is found, returns <tt>0</tt> 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) + def delete_by(*args) + where(*args).delete_all + end + # 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 @@ -511,6 +637,7 @@ module ActiveRecord def reset @delegate_to_klass = false + @_deprecated_scope_source = nil @to_sql = @arel = @loaded = @should_eager_load = nil @records = [].freeze @offsets = {} @@ -619,14 +746,46 @@ module ActiveRecord end end + attr_reader :_deprecated_scope_source # :nodoc: + protected + attr_writer :_deprecated_scope_source # :nodoc: def load_records(records) @records = records.freeze @loaded = true end + def null_relation? # :nodoc: + is_a?(NullRelation) + end + private + def already_in_scope? + @delegate_to_klass && begin + scope = klass.current_scope(true) + scope && !scope._deprecated_scope_source + end + end + + def _deprecated_spawn(name) + spawn.tap { |scope| scope._deprecated_scope_source = name } + end + + def _deprecated_scope_block(name, &block) + -> record do + klass.current_scope = _deprecated_spawn(name) + yield record if block_given? + end + end + + def _scoping(scope) + previous, klass.current_scope = klass.current_scope(true), scope + yield + ensure + klass.current_scope = previous + end + def _substitute_values(values) values.map do |name, value| attr = arel_attribute(name) @@ -638,12 +797,19 @@ module ActiveRecord end end + 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 + def exec_queries(&block) skip_query_cache_if_necessary do @records = if eager_loading? apply_join_dependency do |relation, join_dependency| - if ActiveRecord::NullRelation === relation + if relation.null_relation? [] else relation = join_dependency.apply_column_aliases(relation) |