diff options
Diffstat (limited to 'activerecord/lib/active_record/relation/query_methods.rb')
| -rw-r--r-- | activerecord/lib/active_record/relation/query_methods.rb | 394 |
1 files changed, 287 insertions, 107 deletions
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb index 670ba0987d..19fe8155d9 100644 --- a/activerecord/lib/active_record/relation/query_methods.rb +++ b/activerecord/lib/active_record/relation/query_methods.rb @@ -5,40 +5,90 @@ module ActiveRecord module QueryMethods extend ActiveSupport::Concern - attr_accessor :includes_values, :eager_load_values, :preload_values, - :select_values, :group_values, :order_values, :joins_values, - :where_values, :having_values, :bind_values, - :limit_value, :offset_value, :lock_value, :readonly_value, :create_with_value, - :from_value, :reorder_value, :reverse_order_value + Relation::MULTI_VALUE_METHODS.each do |name| + class_eval <<-CODE, __FILE__, __LINE__ + 1 + def #{name}_values # def select_values + @values[:#{name}] || [] # @values[:select] || [] + end # end + # + def #{name}_values=(values) # def select_values=(values) + @values[:#{name}] = values # @values[:select] = values + end # end + CODE + end + + (Relation::SINGLE_VALUE_METHODS - [:create_with]).each do |name| + class_eval <<-CODE, __FILE__, __LINE__ + 1 + def #{name}_value # def readonly_value + @values[:#{name}] # @values[:readonly] + end # end + # + def #{name}_value=(value) # def readonly_value=(value) + @values[:#{name}] = value # @values[:readonly] = value + end # end + CODE + end + + def create_with_value + @values[:create_with] || {} + end + + def create_with_value=(value) + @values[:create_with] = value + end + + alias extensions extending_values def includes(*args) - args.reject! {|a| a.blank? } + args.empty? ? self : spawn.includes!(*args) + end - return self if args.empty? + def includes!(*args) + args.reject! {|a| a.blank? } - relation = clone - relation.includes_values = (relation.includes_values + args).flatten.uniq - relation + self.includes_values = (includes_values + args).flatten.uniq + self end def eager_load(*args) - return self if args.blank? + args.blank? ? self : spawn.eager_load!(*args) + end - relation = clone - relation.eager_load_values += args - relation + def eager_load!(*args) + self.eager_load_values += args + self end def preload(*args) - return self if args.blank? + args.blank? ? self : spawn.preload!(*args) + end + + def preload!(*args) + self.preload_values += args + self + end - relation = clone - relation.preload_values += args - relation + # Used to indicate that an association is referenced by an SQL string, and should + # therefore be JOINed in any query rather than loaded separately. + # + # For example: + # + # User.includes(:posts).where("posts.name = 'foo'") + # # => Doesn't JOIN the posts table, resulting in an error. + # + # User.includes(:posts).where("posts.name = 'foo'").references(:posts) + # # => Query now knows the string references posts, so adds a JOIN + def references(*args) + args.blank? ? self : spawn.references!(*args) + end + + def references!(*args) + self.references_values = (references_values + args.flatten.map(&:to_s)).uniq + self end # Works in two unique ways. - # + # # First: takes a block so it can be used just like Array#select. # # Model.scoped.select { |m| m.field == value } @@ -56,129 +106,244 @@ module ActiveRecord # array, it actually returns a relation object and can have other query # methods appended to it, such as the other methods in ActiveRecord::QueryMethods. # - # This method will also take multiple parameters: + # The argument to the method can also be an array of fields. # - # >> Model.select(:field, :other_field, :and_one_more) + # >> Model.select([:field, :other_field, :and_one_more]) # => [#<Model field: "value", other_field: "value", and_one_more: "value">] # - # Any attributes that do not have fields retrieved by a select - # will return `nil` when the getter method for that attribute is used: + # Accessing attributes of an object that do not have fields retrieved by a select + # will throw <tt>ActiveModel::MissingAttributeError</tt>: # # >> Model.select(:field).first.other_field - # => nil + # => ActiveModel::MissingAttributeError: missing attribute: other_field def select(value = Proc.new) if block_given? - to_a.select {|*block_args| value.call(*block_args) } + to_a.select { |*block_args| value.call(*block_args) } else - relation = clone - relation.select_values += Array.wrap(value) - relation + spawn.select!(value) end end + def select!(value) + self.select_values += Array.wrap(value) + self + end + def group(*args) - return self if args.blank? + args.blank? ? self : spawn.group!(*args) + end - relation = clone - relation.group_values += args.flatten - relation + def group!(*args) + self.group_values += args.flatten + self end def order(*args) - return self if args.blank? + args.blank? ? self : spawn.order!(*args) + end + + def order!(*args) + args = args.flatten - relation = clone - relation.order_values += args.flatten - relation + references = args.reject { |arg| Arel::Node === arg } + .map { |arg| arg =~ /^([a-zA-Z]\w*)\.(\w+)/ && $1 } + .compact + references!(references) if references.any? + + self.order_values += args + self end + # Replaces any existing order defined on the relation with the specified order. + # + # User.order('email DESC').reorder('id ASC') # generated SQL has 'ORDER BY id ASC' + # + # Subsequent calls to order on the same relation will be appended. For example: + # + # User.order('email DESC').reorder('id ASC').order('name ASC') + # + # generates a query with 'ORDER BY id ASC, name ASC'. + # def reorder(*args) - return self if args.blank? + args.blank? ? self : spawn.reorder!(*args) + end - relation = clone - relation.reorder_value = args.flatten - relation + def reorder!(*args) + self.reordering_value = true + self.order_values = args.flatten + self end def joins(*args) - return self if args.compact.blank? - - relation = clone + args.compact.blank? ? self : spawn.joins!(*args) + end + def joins!(*args) args.flatten! - relation.joins_values += args - relation + self.joins_values += args + self end def bind(value) - relation = clone - relation.bind_values += [value] - relation + spawn.bind!(value) + end + + def bind!(value) + self.bind_values += [value] + self end def where(opts, *rest) - return self if opts.blank? + opts.blank? ? self : spawn.where!(opts, *rest) + end - relation = clone - relation.where_values += build_where(opts, rest) - relation + def where!(opts, *rest) + references!(PredicateBuilder.references(opts)) if Hash === opts + + self.where_values += build_where(opts, rest) + self end def having(opts, *rest) - return self if opts.blank? + opts.blank? ? self : spawn.having!(opts, *rest) + end + + def having!(opts, *rest) + references!(PredicateBuilder.references(opts)) if Hash === opts - relation = clone - relation.having_values += build_where(opts, rest) - relation + self.having_values += build_where(opts, rest) + self end def limit(value) - relation = clone - relation.limit_value = value - relation + spawn.limit!(value) + end + + def limit!(value) + self.limit_value = value + self end def offset(value) - relation = clone - relation.offset_value = value - relation + spawn.offset!(value) + end + + def offset!(value) + self.offset_value = value + self end def lock(locks = true) - relation = clone + spawn.lock!(locks) + end + def lock!(locks = true) case locks when String, TrueClass, NilClass - relation.lock_value = locks || true + self.lock_value = locks || true else - relation.lock_value = false + self.lock_value = false end - relation + self + end + + # Returns a chainable relation with zero records, specifically an + # instance of the NullRelation class. + # + # The returned NullRelation inherits from Relation and implements the + # Null Object pattern so it is an object with defined null behavior: + # it always returns an empty array of records and does not query the database. + # + # Any subsequent condition chained to the returned relation will continue + # generating an empty relation and will not fire any query to the database. + # + # Used in cases where a method or scope could return zero records but the + # result needs to be chainable. + # + # For example: + # + # @posts = current_user.visible_posts.where(:name => params[:name]) + # # => the visible_posts method is expected to return a chainable Relation + # + # def visible_posts + # case role + # when 'Country Manager' + # Post.where(:country => country) + # when 'Reviewer' + # Post.published + # when 'Bad User' + # Post.none # => returning [] instead breaks the previous code + # end + # end + # + def none + NullRelation.new(@klass, @table) end def readonly(value = true) - relation = clone - relation.readonly_value = value - relation + spawn.readonly!(value) + end + + def readonly!(value = true) + self.readonly_value = value + self end def create_with(value) - relation = clone - relation.create_with_value = value ? create_with_value.merge(value) : {} - relation + spawn.create_with!(value) + end + + def create_with!(value) + self.create_with_value = value ? create_with_value.merge(value) : {} + self + end + + # Specifies table from which the records will be fetched. For example: + # + # Topic.select('title').from('posts') + # #=> SELECT title FROM posts + # + # Can accept other relation objects. For example: + # + # Topic.select('title').from(Topics.approved) + # # => SELECT title FROM (SELECT * FROM topics WHERE approved = 't') subquery + # + # Topics.select('a.title').from(Topics.approved, :a) + # # => SELECT a.title FROM (SELECT * FROM topics WHERE approved = 't') a + # + def from(value, subquery_name = nil) + spawn.from!(value, subquery_name) + end + + def from!(value, subquery_name = nil) + self.from_value = [value, subquery_name] + self + end + + # Specifies whether the records should be unique or not. For example: + # + # User.select(:name) + # # => Might return two records with the same name + # + # User.select(:name).uniq + # # => Returns 1 record per unique name + # + # User.select(:name).uniq.uniq(false) + # # => You can also remove the uniqueness + def uniq(value = true) + spawn.uniq!(value) end - def from(value) - relation = clone - relation.from_value = value - relation + def uniq!(value = true) + self.uniq_value = value + self end # Used to extend a scope with additional methods, either through - # a module or through a block provided. - # + # a module or through a block provided. + # # The object returned is a relation, which can be further extended. # # === Using a module @@ -200,7 +365,7 @@ module ActiveRecord # # scope = Model.scoped.extending do # def page(number) - # # pagination code goes here + # # pagination code goes here # end # end # scope.page(params[:page]) @@ -209,23 +374,33 @@ module ActiveRecord # # scope = Model.scoped.extending(Pagination) do # def per_page(number) - # # pagination code goes here + # # pagination code goes here # end # end - def extending(*modules) - modules << Module.new(&Proc.new) if block_given? + def extending(*modules, &block) + if modules.any? || block + spawn.extending!(*modules, &block) + else + self + end + end - return self if modules.empty? + def extending!(*modules, &block) + modules << Module.new(&block) if block_given? - relation = clone - relation.send(:apply_modules, modules.flatten) - relation + self.extending_values = modules.flatten + extend(*extending_values) if extending_values.any? + + self end def reverse_order - relation = clone - relation.reverse_order_value = !relation.reverse_order_value - relation + spawn.reverse_order! + end + + def reverse_order! + self.reverse_order_value = !reverse_order_value + self end def arel @@ -235,25 +410,26 @@ module ActiveRecord def build_arel arel = table.from table - build_joins(arel, @joins_values) unless @joins_values.empty? + build_joins(arel, joins_values) unless joins_values.empty? - collapse_wheres(arel, (@where_values - ['']).uniq) + collapse_wheres(arel, (where_values - ['']).uniq) - arel.having(*@having_values.uniq.reject{|h| h.blank?}) unless @having_values.empty? + arel.having(*having_values.uniq.reject{|h| h.blank?}) unless having_values.empty? - arel.take(connection.sanitize_limit(@limit_value)) if @limit_value - arel.skip(@offset_value) if @offset_value + arel.take(connection.sanitize_limit(limit_value)) if limit_value + arel.skip(offset_value.to_i) if offset_value - arel.group(*@group_values.uniq.reject{|g| g.blank?}) unless @group_values.empty? + arel.group(*group_values.uniq.reject{|g| g.blank?}) unless group_values.empty? - order = @reorder_value ? @reorder_value : @order_values - order = reverse_sql_order(order) if @reverse_order_value + order = order_values + order = reverse_sql_order(order) if reverse_order_value arel.order(*order.uniq.reject{|o| o.blank?}) unless order.empty? - build_select(arel, @select_values.uniq) + build_select(arel, select_values.uniq) - arel.from(@from_value) if @from_value - arel.lock(@lock_value) if @lock_value + arel.distinct(uniq_value) + arel.from(build_from) if from_value + arel.lock(lock_value) if lock_value arel end @@ -301,6 +477,17 @@ module ActiveRecord end end + def build_from + opts, name = from_value + case opts + when Relation + name ||= 'subquery' + opts.arel.as(name.to_s) + else + opts + end + end + def build_joins(manager, joins) buckets = joins.group_by do |join| case join @@ -355,13 +542,6 @@ module ActiveRecord end end - def apply_modules(modules) - unless modules.empty? - @extensions += modules - modules.each {|extension| extend(extension) } - end - end - def reverse_sql_order(order_query) order_query = ["#{quoted_table_name}.#{quoted_primary_key} ASC"] if order_query.empty? |