diff options
Diffstat (limited to 'activerecord/lib/active_record/relation')
8 files changed, 926 insertions, 595 deletions
diff --git a/activerecord/lib/active_record/relation/batches.rb b/activerecord/lib/active_record/relation/batches.rb index 2fd89882ff..4d14506965 100644 --- a/activerecord/lib/active_record/relation/batches.rb +++ b/activerecord/lib/active_record/relation/batches.rb @@ -1,21 +1,26 @@ -require 'active_support/core_ext/object/blank' module ActiveRecord module Batches - # Yields each record that was found by the find +options+. The find is - # performed by find_in_batches with a batch size of 1000 (or as - # specified by the <tt>:batch_size</tt> option). + # Looping through a collection of records from the database + # (using the +all+ method, for example) is very inefficient + # since it will try to instantiate all the objects at once. # - # Example: + # In that case, batch processing methods allow you to work + # with the records in batches, thereby greatly reducing memory consumption. + # + # The #find_each method uses #find_in_batches with a batch size of 1000 (or as + # specified by the +:batch_size+ option). + # + # Person.all.find_each do |person| + # person.do_awesome_stuff + # end # # Person.where("age > 21").find_each do |person| # person.party_all_night! # end # - # Note: This method is only intended to use for batch processing of - # large amounts of records that wouldn't fit in memory all at once. If - # you just need to loop over less than 1000 records, it's probably - # better just to use the regular find methods. + # You can also pass the +:start+ option to specify + # an offset to control the starting point. def find_each(options = {}) find_in_batches(options) do |records| records.each { |record| yield record } @@ -23,14 +28,14 @@ module ActiveRecord end # Yields each batch of records that was found by the find +options+ as - # an array. The size of each batch is set by the <tt>:batch_size</tt> + # an array. The size of each batch is set by the +:batch_size+ # option; the default is 1000. # # You can control the starting point for the batch processing by - # supplying the <tt>:start</tt> option. This is especially useful if you + # supplying the +:start+ option. This is especially useful if you # want multiple workers dealing with the same processing queue. You can # make worker 1 handle all the records between id 0 and 10,000 and - # worker 2 handle from 10,000 and beyond (by setting the <tt>:start</tt> + # worker 2 handle from 10,000 and beyond (by setting the +:start+ # option on that worker). # # It's not possible to set the order. That is automatically set to @@ -39,31 +44,29 @@ module ActiveRecord # primary keys. You can't set the limit either, that's used to control # the batch sizes. # - # Example: - # # Person.where("age > 21").find_in_batches do |group| # sleep(50) # Make sure it doesn't get too crowded in there! # group.each { |person| person.party_all_night! } # end + # + # # Let's process the next 2000 records + # Person.all.find_in_batches(start: 2000, batch_size: 2000) do |group| + # group.each { |person| person.party_all_night! } + # end def find_in_batches(options = {}) + options.assert_valid_keys(:start, :batch_size) + relation = self unless arel.orders.blank? && arel.taken.blank? ActiveRecord::Base.logger.warn("Scoped order and limit are ignored, it's forced to be batch order and batch size") end - if (finder_options = options.except(:start, :batch_size)).present? - raise "You can't specify an order, it's forced to be #{batch_order}" if options[:order].present? - raise "You can't specify a limit, it's forced to be the batch_size" if options[:limit].present? - - relation = apply_finder_options(finder_options) - end - start = options.delete(:start).to_i batch_size = options.delete(:batch_size) || 1000 relation = relation.reorder(batch_order).limit(batch_size) - records = relation.where(table[primary_key].gteq(start)).all + records = relation.where(table[primary_key].gteq(start)).to_a while records.any? records_size = records.size diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb index 50239f7cb2..7c43d844d0 100644 --- a/activerecord/lib/active_record/relation/calculations.rb +++ b/activerecord/lib/active_record/relation/calculations.rb @@ -1,61 +1,30 @@ -require 'active_support/core_ext/object/blank' require 'active_support/core_ext/object/try' module ActiveRecord module Calculations - # Count operates using three different approaches. - # - # * Count all: By not passing any parameters to count, it will return a count of all the rows for the model. - # * Count using column: By passing a column name to count, it will return a count of all the - # rows for the model with supplied column present. - # * Count using options will find the row count matched by the options used. - # - # The third approach, count using options, accepts an option hash as the only parameter. The options are: - # - # * <tt>:conditions</tt>: An SQL fragment like "administrator = 1" or [ "user_name = ?", username ]. - # See conditions in the intro to ActiveRecord::Base. - # * <tt>:joins</tt>: Either an SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id" - # (rarely needed) or named associations in the same form used for the <tt>:include</tt> option, which will - # perform an INNER JOIN on the associated table(s). If the value is a string, then the records - # will be returned read-only since they will have attributes that do not correspond to the table's columns. - # Pass <tt>:readonly => false</tt> to override. - # * <tt>:include</tt>: Named associations that should be loaded alongside using LEFT OUTER JOINs. - # The symbols named refer to already defined associations. When using named associations, count - # returns the number of DISTINCT items for the model you're counting. - # See eager loading under Associations. - # * <tt>:order</tt>: An SQL fragment like "created_at DESC, name" (really only used with GROUP BY calculations). - # * <tt>:group</tt>: An attribute name by which the result should be grouped. Uses the GROUP BY SQL-clause. - # * <tt>:select</tt>: By default, this is * as in SELECT * FROM, but can be changed if you, for example, - # want to do a join but not include the joined columns. - # * <tt>:distinct</tt>: Set this to true to make this a distinct calculation, such as - # SELECT COUNT(DISTINCT posts.id) ... - # * <tt>:from</tt> - By default, this is the table name of the class, but can be changed to an - # alternate table name (or even the name of a database view). - # - # Examples for counting all: - # Person.count # returns the total count of all people - # - # Examples for counting by column: - # Person.count(:age) # returns the total count of all people whose age is present in database - # - # Examples for count with options: - # Person.count(:conditions => "age > 26") - # - # # because of the named association, it finds the DISTINCT count using LEFT OUTER JOIN. - # Person.count(:conditions => "age > 26 AND job.salary > 60000", :include => :job) - # - # # finds the number of rows matching the conditions and joins. - # Person.count(:conditions => "age > 26 AND job.salary > 60000", - # :joins => "LEFT JOIN jobs on jobs.person_id = person.id") - # - # Person.count('id', :conditions => "age > 26") # Performs a COUNT(id) - # Person.count(:all, :conditions => "age > 26") # Performs a COUNT(*) (:all is an alias for '*') - # - # Note: <tt>Person.count(:all)</tt> will not work because it will use <tt>:all</tt> as the condition. - # Use Person.count instead. + # Count the records. + # + # Person.count + # # => the total count of all people + # + # Person.count(:age) + # # => returns the total count of all people whose age is present in database + # + # Person.count(:all) + # # => performs a COUNT(*) (:all is an alias for '*') + # + # Person.count(:age, distinct: true) + # # => counts the number of different age values + # + # Person.where("age > 26").count { |person| person.gender == 'female' } + # # => queries people where "age > 26" then count the loaded results filtering by gender def count(column_name = nil, options = {}) - column_name, options = nil, column_name if column_name.is_a?(Hash) - calculate(:count, column_name, options) + if block_given? + self.to_a.count { |item| yield item } + else + column_name, options = nil, column_name if column_name.is_a?(Hash) + calculate(:count, column_name, options) + end end # Calculates the average value on a given column. Returns +nil+ if there's @@ -89,30 +58,35 @@ module ActiveRecord # +calculate+ for examples with options. # # Person.sum('age') # => 4562 + # # => returns the total sum of all people's age + # + # Person.where('age > 100').sum { |person| person.age - 100 } + # # queries people where "age > 100" then perform a sum calculation with the block returns def sum(*args) if block_given? - self.to_a.sum(*args) {|*block_args| yield(*block_args)} + self.to_a.sum(*args) { |item| yield item } else calculate(:sum, *args) end end # This calculates aggregate values in the given column. Methods for count, sum, average, - # minimum, and maximum have been added as shortcuts. Options such as <tt>:conditions</tt>, - # <tt>:order</tt>, <tt>:group</tt>, <tt>:having</tt>, and <tt>:joins</tt> can be passed to customize the query. + # minimum, and maximum have been added as shortcuts. # # There are two basic forms of output: + # # * Single aggregate value: The single value is type cast to Fixnum for COUNT, Float # for AVG, and the given column's type for everything else. - # * Grouped values: This returns an ordered hash of the values and groups them by the - # <tt>:group</tt> option. It takes either a column name, or the name of a belongs_to association. # - # values = Person.maximum(:age, :group => 'last_name') + # * Grouped values: This returns an ordered hash of the values and groups them. It + # takes either a column name, or the name of a belongs_to association. + # + # values = Person.group('last_name').maximum(:age) # puts values["Drake"] # => 43 # # drake = Family.find_by_last_name('Drake') - # values = Person.maximum(:age, :group => :family) # Person belongs_to :family + # values = Person.group(:family).maximum(:age) # Person belongs_to :family # puts values[drake] # => 43 # @@ -120,73 +94,113 @@ module ActiveRecord # ... # end # - # Options: - # * <tt>:conditions</tt> - An SQL fragment like "administrator = 1" or [ "user_name = ?", username ]. - # See conditions in the intro to ActiveRecord::Base. - # * <tt>:include</tt>: Eager loading, see Associations for details. Since calculations don't load anything, - # the purpose of this is to access fields on joined tables in your conditions, order, or group clauses. - # * <tt>:joins</tt> - An SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id". - # (Rarely needed). - # The records will be returned read-only since they will have attributes that do not correspond to the - # table's columns. - # * <tt>:order</tt> - An SQL fragment like "created_at DESC, name" (really only used with GROUP BY calculations). - # * <tt>:group</tt> - An attribute name by which the result should be grouped. Uses the GROUP BY SQL-clause. - # * <tt>:select</tt> - By default, this is * as in SELECT * FROM, but can be changed if you for example - # want to do a join, but not include the joined columns. - # * <tt>:distinct</tt> - Set this to true to make this a distinct calculation, such as - # SELECT COUNT(DISTINCT posts.id) ... - # # Examples: # Person.calculate(:count, :all) # The same as Person.count # Person.average(:age) # SELECT AVG(age) FROM people... - # Person.minimum(:age, :conditions => ['last_name != ?', 'Drake']) # Selects the minimum age for - # # everyone with a last name other than 'Drake' # # # Selects the minimum age for any family without any minors - # Person.minimum(:age, :having => 'min(age) > 17', :group => :last_name) + # Person.group(:last_name).having("min(age) > 17").minimum(:age) # # Person.sum("2 * age") def calculate(operation, column_name, options = {}) - if options.except(:distinct).present? - apply_finder_options(options.except(:distinct)).calculate(operation, column_name, :distinct => options[:distinct]) - else - relation = with_default_scope + relation = with_default_scope - if relation.equal?(self) - if eager_loading? || (includes_values.present? && references_eager_loaded_tables?) - construct_relation_for_association_calculations.calculate(operation, column_name, options) - else - perform_calculation(operation, column_name, options) - end + if relation.equal?(self) + if has_include?(column_name) + construct_relation_for_association_calculations.calculate(operation, column_name, options) else - relation.calculate(operation, column_name, options) + perform_calculation(operation, column_name, options) end + else + relation.calculate(operation, column_name, options) end rescue ThrowResult 0 end - # This method is designed to perform select by a single column as direct SQL query - # Returns <tt>Array</tt> with values of the specified column name - # The values has same data type as column. + # Use <tt>pluck</tt> as a shortcut to select a single attribute without + # loading a bunch of records just to grab one attribute you want. + # + # Person.pluck(:name) + # + # instead of + # + # Person.all.map(&:name) + # + # Pluck returns an <tt>Array</tt> of attribute values type-casted to match + # the plucked column name, if it can be deduced. Plucking an SQL fragment + # returns String values by default. # # Examples: # - # Person.pluck(:id) # SELECT people.id FROM people - # Person.uniq.pluck(:role) # SELECT DISTINCT role FROM people - # Person.where(:confirmed => true).limit(5).pluck(:id) + # Person.pluck(:id) + # # SELECT people.id FROM people + # # => [1, 2, 3] + # + # Person.pluck(:id, :name) + # # SELECT people.id, people.name FROM people + # # => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']] + # + # Person.uniq.pluck(:role) + # # SELECT DISTINCT role FROM people + # # => ['admin', 'member', 'guest'] + # + # Person.where(:age => 21).limit(5).pluck(:id) + # # SELECT people.id FROM people WHERE people.age = 21 LIMIT 5 + # # => [2, 3] + # + # Person.pluck('DATEDIFF(updated_at, created_at)') + # # SELECT DATEDIFF(updated_at, created_at) FROM people + # # => ['0', '27761', '173'] # - def pluck(column_name) - if column_name.is_a?(Symbol) && column_names.include?(column_name.to_s) - column_name = "#{table_name}.#{column_name}" + def pluck(*column_names) + column_names.map! do |column_name| + if column_name.is_a?(Symbol) && self.column_names.include?(column_name.to_s) + "#{connection.quote_table_name(table_name)}.#{connection.quote_column_name(column_name)}" + else + column_name + end end - klass.connection.select_all(select(column_name).arel).map! do |attributes| - klass.type_cast_attribute(attributes.keys.first, klass.initialize_attributes(attributes)) + + if has_include?(column_names.first) + construct_relation_for_association_calculations.pluck(*column_names) + else + result = klass.connection.select_all(select(column_names).arel, nil, bind_values) + columns = result.columns.map do |key| + klass.column_types.fetch(key) { + result.column_types.fetch(key) { + Class.new { def type_cast(v); v; end }.new + } + } + end + + result = result.map do |attributes| + values = klass.initialize_attributes(attributes).values + + columns.zip(values).map do |column, value| + column.type_cast(value) + end + end + columns.one? ? result.map!(&:first) : result end end + # Pluck all the ID's for the relation using the table's primary key + # + # Examples: + # + # Person.ids # SELECT people.id FROM people + # Person.joins(:companies).ids # SELECT people.id FROM people INNER JOIN companies ON companies.person_id = people.id + def ids + pluck primary_key + end + private + def has_include?(column_name) + eager_loading? || (includes_values.present? && (column_name || references_eager_loaded_tables?)) + end + def perform_calculation(operation, column_name, options = {}) operation = operation.to_s.downcase @@ -204,7 +218,7 @@ module ActiveRecord distinct = nil if column_name =~ /\s*DISTINCT\s+/i end - if @group_values.any? + if group_values.any? execute_grouped_calculation(operation, column_name, distinct) else execute_simple_calculation(operation, column_name, distinct) @@ -242,14 +256,21 @@ module ActiveRecord query_builder = relation.arel end - type_cast_calculated_value(@klass.connection.select_value(query_builder), column_for(column_name), operation) + result = @klass.connection.select_value(query_builder, nil, relation.bind_values) + type_cast_calculated_value(result, column_for(column_name), operation) end def execute_grouped_calculation(operation, column_name, distinct) #:nodoc: - group_attr = @group_values - association = @klass.reflect_on_association(group_attr.first.to_sym) - associated = group_attr.size == 1 && association && association.macro == :belongs_to # only count belongs_to associations - group_fields = Array(associated ? association.foreign_key : group_attr) + group_attrs = group_values + + if group_attrs.first.respond_to?(:to_sym) + association = @klass.reflect_on_association(group_attrs.first.to_sym) + associated = group_attrs.size == 1 && association && association.macro == :belongs_to # only count belongs_to associations + group_fields = Array(associated ? association.foreign_key : group_attrs) + else + group_fields = group_attrs + end + group_aliases = group_fields.map { |field| column_alias_for(field) } group_columns = group_aliases.zip(group_fields).map { |aliaz,field| [aliaz, column_for(field)] @@ -269,16 +290,20 @@ module ActiveRecord operation, distinct).as(aggregate_alias) ] - select_values += @select_values unless @having_values.empty? + select_values += select_values unless having_values.empty? select_values.concat group_fields.zip(group_aliases).map { |field,aliaz| - "#{field} AS #{aliaz}" + if field.respond_to?(:as) + field.as(aliaz) + else + "#{field} AS #{aliaz}" + end } - relation = except(:group).group(group.join(',')) + relation = except(:group).group(group) relation.select_values = select_values - calculated_data = @klass.connection.select_all(relation) + calculated_data = @klass.connection.select_all(relation, nil, bind_values) if association key_ids = calculated_data.collect { |row| row[group_aliases.first] } @@ -286,11 +311,11 @@ module ActiveRecord key_records = Hash[key_records.map { |r| [r.id, r] }] end - ActiveSupport::OrderedHash[calculated_data.map do |row| - key = group_columns.map { |aliaz, column| + Hash[calculated_data.map do |row| + key = group_columns.map { |aliaz, column| type_cast_calculated_value(row[aliaz], column) } - key = key.first if key.size == 1 + key = key.first if key.size == 1 key = key_records[key] if associated [key, type_cast_calculated_value(row[aggregate_alias], column_for(column_name), operation)] end] @@ -305,6 +330,7 @@ module ActiveRecord # column_alias_for("count(*)") # => "count_all" # column_alias_for("count", "id") # => "count_id" def column_alias_for(*keys) + keys.map! {|k| k.respond_to?(:to_sql) ? k.to_sql : k} table_name = keys.join(' ') table_name.downcase! table_name.gsub!(/\*/, 'all') @@ -316,7 +342,7 @@ module ActiveRecord end def column_for(field) - field_name = field.to_s.split('.').last + field_name = field.respond_to?(:name) ? field.name.to_s : field.to_s.split('.').last @klass.columns.detect { |c| c.name.to_s == field_name } end @@ -334,8 +360,8 @@ module ActiveRecord end def select_for_count - if @select_values.present? - select = @select_values.join(", ") + if select_values.present? + select = select_values.join(", ") select if select !~ /[,*]/ end end diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb index f5fdf437bf..ab8b36c8ab 100644 --- a/activerecord/lib/active_record/relation/delegation.rb +++ b/activerecord/lib/active_record/relation/delegation.rb @@ -1,7 +1,6 @@ -require 'active_support/core_ext/module/delegation' module ActiveRecord - module Delegation + module Delegation # :nodoc: # Set up common delegations for performance (avoids method_missing) delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to_ary, :to => :to_a delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key, @@ -32,12 +31,12 @@ module ActiveRecord protected def method_missing(method, *args, &block) - if Array.method_defined?(method) - ::ActiveRecord::Delegation.delegate method, :to => :to_a - to_a.send(method, *args, &block) - elsif @klass.respond_to?(method) + if @klass.respond_to?(method) ::ActiveRecord::Delegation.delegate_to_scoped_klass(method) scoping { @klass.send(method, *args, &block) } + elsif Array.method_defined?(method) + ::ActiveRecord::Delegation.delegate method, :to => :to_a + to_a.send(method, *args, &block) elsif arel.respond_to?(method) ::ActiveRecord::Delegation.delegate method, :to => :arel arel.send(method, *args, &block) @@ -46,4 +45,4 @@ module ActiveRecord end end end -end
\ No newline at end of file +end diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb index f1ac421a50..84aaa39fed 100644 --- a/activerecord/lib/active_record/relation/finder_methods.rb +++ b/activerecord/lib/active_record/relation/finder_methods.rb @@ -1,85 +1,23 @@ -require 'active_support/core_ext/object/blank' require 'active_support/core_ext/hash/indifferent_access' module ActiveRecord module FinderMethods - # Find operates with four different retrieval approaches: + # Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]). + # If no record can be found for all of the listed ids, then RecordNotFound will be raised. If the primary key + # is an integer, find by id coerces its arguments using +to_i+. # - # * Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]). - # If no record can be found for all of the listed ids, then RecordNotFound will be raised. - # * Find first - This will return the first record matched by the options used. These options can either be specific - # conditions or merely an order. If no record can be matched, +nil+ is returned. Use - # <tt>Model.find(:first, *args)</tt> or its shortcut <tt>Model.first(*args)</tt>. - # * Find last - This will return the last record matched by the options used. These options can either be specific - # conditions or merely an order. If no record can be matched, +nil+ is returned. Use - # <tt>Model.find(:last, *args)</tt> or its shortcut <tt>Model.last(*args)</tt>. - # * Find all - This will return all the records matched by the options used. - # If no records are found, an empty array is returned. Use - # <tt>Model.find(:all, *args)</tt> or its shortcut <tt>Model.all(*args)</tt>. - # - # All approaches accept an options hash as their last parameter. - # - # ==== Options - # - # * <tt>:conditions</tt> - An SQL fragment like "administrator = 1", <tt>["user_name = ?", username]</tt>, - # or <tt>["user_name = :user_name", { :user_name => user_name }]</tt>. See conditions in the intro. - # * <tt>:order</tt> - An SQL fragment like "created_at DESC, name". - # * <tt>:group</tt> - An attribute name by which the result should be grouped. Uses the <tt>GROUP BY</tt> SQL-clause. - # * <tt>:having</tt> - Combined with +:group+ this can be used to filter the records that a - # <tt>GROUP BY</tt> returns. Uses the <tt>HAVING</tt> SQL-clause. - # * <tt>:limit</tt> - An integer determining the limit on the number of rows that should be returned. - # * <tt>:offset</tt> - An integer determining the offset from where the rows should be fetched. So at 5, - # it would skip rows 0 through 4. - # * <tt>:joins</tt> - Either an SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id" (rarely needed), - # named associations in the same form used for the <tt>:include</tt> option, which will perform an - # <tt>INNER JOIN</tt> on the associated table(s), - # or an array containing a mixture of both strings and named associations. - # If the value is a string, then the records will be returned read-only since they will - # have attributes that do not correspond to the table's columns. - # Pass <tt>:readonly => false</tt> to override. - # * <tt>:include</tt> - Names associations that should be loaded alongside. The symbols named refer - # to already defined associations. See eager loading under Associations. - # * <tt>:select</tt> - By default, this is "*" as in "SELECT * FROM", but can be changed if you, - # for example, want to do a join but not include the joined columns. Takes a string with the SELECT SQL fragment (e.g. "id, name"). - # * <tt>:from</tt> - By default, this is the table name of the class, but can be changed - # to an alternate table name (or even the name of a database view). - # * <tt>:readonly</tt> - Mark the returned records read-only so they cannot be saved or updated. - # * <tt>:lock</tt> - An SQL fragment like "FOR UPDATE" or "LOCK IN SHARE MODE". - # <tt>:lock => true</tt> gives connection's default exclusive lock, usually "FOR UPDATE". - # - # ==== Examples - # - # # find by id # Person.find(1) # returns the object for ID = 1 + # Person.find("1") # returns the object for ID = 1 # Person.find(1, 2, 6) # returns an array for objects with IDs in (1, 2, 6) # Person.find([7, 17]) # returns an array for objects with IDs in (7, 17) # Person.find([1]) # returns an array for the object with ID = 1 # Person.where("administrator = 1").order("created_on DESC").find(1) # # Note that returned records may not be in the same order as the ids you - # provide since database rows are unordered. Give an explicit <tt>:order</tt> + # provide since database rows are unordered. Give an explicit <tt>order</tt> # to ensure the results are sorted. # - # ==== Examples - # - # # find first - # Person.first # returns the first object fetched by SELECT * FROM people - # Person.where(["user_name = ?", user_name]).first - # Person.where(["user_name = :u", { :u => user_name }]).first - # Person.order("created_on DESC").offset(5).first - # - # # find last - # Person.last # returns the last object fetched by SELECT * FROM people - # Person.where(["user_name = ?", user_name]).last - # Person.order("created_on DESC").offset(5).last - # - # # find all - # Person.all # returns an array of objects for all the rows fetched by SELECT * FROM people - # Person.where(["category IN (?)", categories]).limit(50).all - # Person.where({ :friends => ["Bob", "Steve", "Fred"] }).all - # Person.offset(10).limit(10).all - # Person.includes([:account, :friends]).all - # Person.group("category").all + # ==== Find with lock # # Example for find with a lock: Imagine two concurrent transactions: # each will read <tt>person.visits == 2</tt>, add 1 to it, and save, resulting @@ -93,30 +31,62 @@ module ActiveRecord # person.save! # end def find(*args) - return to_a.find { |*block_args| yield(*block_args) } if block_given? - - options = args.extract_options! - - if options.present? - apply_finder_options(options).find(*args) + if block_given? + to_a.find { |*block_args| yield(*block_args) } else - case args.first - when :first, :last, :all - send(args.first) - else - find_with_ids(*args) - end + find_with_ids(*args) end end - # A convenience wrapper for <tt>find(:first, *args)</tt>. You can pass in all the - # same arguments to this method as you can to <tt>find(:first)</tt>. - def first(*args) - if args.any? - if args.first.kind_of?(Integer) || (loaded? && !args.first.kind_of?(Hash)) - limit(*args).to_a + # Finds the first record matching the specified conditions. There + # is no implied ording so if order matters, you should specify it + # yourself. + # + # If no record is found, returns <tt>nil</tt>. + # + # Post.find_by name: 'Spartacus', rating: 4 + # Post.find_by "published_at < ?", 2.weeks.ago + def find_by(*args) + where(*args).take + end + + # Like <tt>find_by</tt>, except that if no record is found, raises + # an <tt>ActiveRecord::RecordNotFound</tt> error. + def find_by!(*args) + where(*args).take! + end + + # Gives a record (or N records if a parameter is supplied) without any implied + # order. The order will depend on the database implementation. + # If an order is supplied it will be respected. + # + # Person.take # returns an object fetched by SELECT * FROM people + # Person.take(5) # returns 5 objects fetched by SELECT * FROM people LIMIT 5 + # Person.where(["name LIKE '%?'", name]).take + def take(limit = nil) + limit ? limit(limit).to_a : find_take + end + + # Same as +take+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record + # is found. Note that <tt>take!</tt> accepts no arguments. + def take! + take or raise RecordNotFound + end + + # Find the first record (or first N records if a parameter is supplied). + # If no order is defined it will order by primary key. + # + # Person.first # returns the first object fetched by SELECT * FROM people + # Person.where(["user_name = ?", user_name]).first + # Person.where(["user_name = :u", { :u => user_name }]).first + # Person.order("created_on DESC").offset(5).first + # Person.first(3) # returns the first three objects fetched by SELECT * FROM people LIMIT 3 + def first(limit = nil) + if limit + if order_values.empty? && primary_key + order(arel_table[primary_key].asc).limit(limit).to_a else - apply_finder_options(args.first).first + limit(limit).to_a end else find_first @@ -129,18 +99,27 @@ module ActiveRecord first or raise RecordNotFound end - # A convenience wrapper for <tt>find(:last, *args)</tt>. You can pass in all the - # same arguments to this method as you can to <tt>find(:last)</tt>. - def last(*args) - if args.any? - if args.first.kind_of?(Integer) || (loaded? && !args.first.kind_of?(Hash)) - if order_values.empty? - order("#{primary_key} DESC").limit(*args).reverse - else - to_a.last(*args) - end + # Find the last record (or last N records if a parameter is supplied). + # If no order is defined it will order by primary key. + # + # Person.last # returns the last object fetched by SELECT * FROM people + # Person.where(["user_name = ?", user_name]).last + # Person.order("created_on DESC").offset(5).last + # Person.last(3) # returns the last three objects fetched by SELECT * FROM people. + # + # Take note that in that last case, the results are sorted in ascending order: + # + # [#<Person id:2>, #<Person id:3>, #<Person id:4>] + # + # and not: + # + # [#<Person id:4>, #<Person id:3>, #<Person id:2>] + def last(limit = nil) + if limit + if order_values.empty? && primary_key + order(arel_table[primary_key].desc).limit(limit).reverse else - apply_finder_options(args.first).last + to_a.last(limit) end else find_last @@ -153,14 +132,8 @@ module ActiveRecord last or raise RecordNotFound end - # A convenience wrapper for <tt>find(:all, *args)</tt>. You can pass in all the - # same arguments to this method as you can to <tt>find(:all)</tt>. - def all(*args) - args.any? ? apply_finder_options(args.first).to_a : to_a - end - - # Returns true if a record exists in the table that matches the +id+ or - # conditions given, or false otherwise. The argument can take five forms: + # Returns +true+ if a record exists in the table that matches the +id+ or + # conditions given, or +false+ otherwise. The argument can take six forms: # # * Integer - Finds the record with this primary key. # * String - Finds the record with a primary key corresponding to this @@ -168,8 +141,9 @@ module ActiveRecord # * Array - Finds the record that matches these +find+-style conditions # (such as <tt>['color = ?', 'red']</tt>). # * Hash - Finds the record that matches these +find+-style conditions - # (such as <tt>{:color => 'red'}</tt>). - # * No args - Returns false if the table is empty, true otherwise. + # (such as <tt>{color: 'red'}</tt>). + # * +false+ - Returns always +false+. + # * No args - Returns +false+ if the table is empty, +true+ otherwise. # # For more information about specifying conditions as a Hash or Array, # see the Conditions section in the introduction to ActiveRecord::Base. @@ -178,29 +152,30 @@ module ActiveRecord # 'Jamie'</tt>), since it would be sanitized and then queried against # the primary key column, like <tt>id = 'name = \'Jamie\''</tt>. # - # ==== Examples # Person.exists?(5) # Person.exists?('5') - # Person.exists?(:name => "David") # Person.exists?(['name LIKE ?', "%#{query}%"]) + # Person.exists?(name: 'David') + # Person.exists?(false) # Person.exists? - def exists?(id = false) - return false if id.nil? - - id = id.id if ActiveRecord::Model === id + def exists?(conditions = :none) + conditions = conditions.id if ActiveRecord::Model === conditions + return false if !conditions join_dependency = construct_join_dependency_for_association_find relation = construct_relation_for_association_find(join_dependency) - relation = relation.except(:select, :order).select("1").limit(1) + relation = relation.except(:select, :order).select("1 AS one").limit(1) - case id + case conditions when Array, Hash - relation = relation.where(id) + relation = relation.where(conditions) else - relation = relation.where(table[primary_key].eq(id)) if id + relation = relation.where(table[primary_key].eq(conditions)) if conditions != :none end - connection.select_value(relation, "#{name} Exists") ? true : false + connection.select_value(relation, "#{name} Exists", relation.bind_values) + rescue ThrowResult + false end protected @@ -208,19 +183,19 @@ module ActiveRecord def find_with_associations join_dependency = construct_join_dependency_for_association_find relation = construct_relation_for_association_find(join_dependency) - rows = connection.select_all(relation, 'SQL', relation.bind_values) + rows = connection.select_all(relation, 'SQL', relation.bind_values.dup) join_dependency.instantiate(rows) rescue ThrowResult [] end def construct_join_dependency_for_association_find - including = (@eager_load_values + @includes_values).uniq + including = (eager_load_values + includes_values).uniq ActiveRecord::Associations::JoinDependency.new(@klass, including, []) end def construct_relation_for_association_calculations - including = (@eager_load_values + @includes_values).uniq + including = (eager_load_values + includes_values).uniq join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, arel.froms.first) relation = except(:includes, :eager_load, :preload) apply_join_dependency(relation, join_dependency) @@ -258,44 +233,6 @@ module ActiveRecord ids_array.empty? ? raise(ThrowResult) : table[primary_key].in(ids_array) end - def find_by_attributes(match, attributes, *args) - conditions = Hash[attributes.map {|a| [a, args[attributes.index(a)]]}] - result = where(conditions).send(match.finder) - - if match.bang? && result.blank? - raise RecordNotFound, "Couldn't find #{@klass.name} with #{conditions.to_a.collect {|p| p.join(' = ')}.join(', ')}" - else - yield(result) if block_given? - result - end - end - - def find_or_instantiator_by_attributes(match, attributes, *args) - options = args.size > 1 && args.last(2).all?{ |a| a.is_a?(Hash) } ? args.extract_options! : {} - protected_attributes_for_create, unprotected_attributes_for_create = {}, {} - args.each_with_index do |arg, i| - if arg.is_a?(Hash) - protected_attributes_for_create = args[i].with_indifferent_access - else - unprotected_attributes_for_create[attributes[i]] = args[i] - end - end - - conditions = (protected_attributes_for_create.merge(unprotected_attributes_for_create)).slice(*attributes).symbolize_keys - - record = where(conditions).first - - unless record - record = @klass.new(protected_attributes_for_create, options) do |r| - r.assign_attributes(unprotected_attributes_for_create, :without_protection => true) - end - yield(record) if block_given? - record.save if match.instantiator == :create - end - - record - end - def find_with_ids(*ids) return to_a.find { |*block_args| yield(*block_args) } if block_given? @@ -318,21 +255,11 @@ module ActiveRecord def find_one(id) id = id.id if ActiveRecord::Base === id - if IdentityMap.enabled? && where_values.blank? && - limit_value.blank? && order_values.blank? && - includes_values.blank? && preload_values.blank? && - readonly_value.nil? && joins_values.blank? && - !@klass.locking_enabled? && - record = IdentityMap.get(@klass, id) - return record - end - column = columns_hash[primary_key] - - substitute = connection.substitute_at(column, @bind_values.length) + substitute = connection.substitute_at(column, bind_values.length) relation = where(table[primary_key].eq(substitute)) - relation.bind_values = [[column, id]] - record = relation.first + relation.bind_values += [[column, id]] + record = relation.take unless record conditions = arel.where_sql @@ -344,18 +271,18 @@ module ActiveRecord end def find_some(ids) - result = where(table[primary_key].in(ids)).all + result = where(table[primary_key].in(ids)).to_a expected_size = - if @limit_value && ids.size > @limit_value - @limit_value + if limit_value && ids.size > limit_value + limit_value else ids.size end # 11 ids with limit 3, offset 9 should give 2 results. - if @offset_value && (ids.size - @offset_value < expected_size) - expected_size = ids.size - @offset_value + if offset_value && (ids.size - offset_value < expected_size) + expected_size = ids.size - offset_value end if result.size == expected_size @@ -370,11 +297,24 @@ module ActiveRecord end end + def find_take + if loaded? + @records.first + else + @take ||= limit(1).to_a.first + end + end + def find_first if loaded? @records.first else - @first ||= limit(1).to_a[0] + @first ||= + if with_default_scope.order_values.empty? && primary_key + order(arel_table[primary_key].asc).limit(1).to_a.first + else + limit(1).to_a.first + end end end @@ -386,7 +326,7 @@ module ActiveRecord if offset_value || limit_value to_a.last else - reverse_order.limit(1).to_a[0] + reverse_order.limit(1).to_a.first end end end diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb new file mode 100644 index 0000000000..e5b50673da --- /dev/null +++ b/activerecord/lib/active_record/relation/merger.rb @@ -0,0 +1,119 @@ +require 'active_support/core_ext/hash/keys' + +module ActiveRecord + class Relation + class HashMerger # :nodoc: + attr_reader :relation, :hash + + def initialize(relation, hash) + hash.assert_valid_keys(*Relation::VALUE_METHODS) + + @relation = relation + @hash = hash + end + + def merge + Merger.new(relation, other).merge + end + + # Applying values to a relation has some side effects. E.g. + # interpolation might take place for where values. So we should + # build a relation to merge in rather than directly merging + # the values. + def other + other = Relation.new(relation.klass, relation.table) + hash.each { |k, v| other.send("#{k}!", v) } + other + end + end + + class Merger # :nodoc: + attr_reader :relation, :values + + def initialize(relation, other) + if other.default_scoped? && other.klass != relation.klass + other = other.with_default_scope + end + + @relation = relation + @values = other.values + end + + def normal_values + Relation::SINGLE_VALUE_METHODS + + Relation::MULTI_VALUE_METHODS - + [:where, :order, :bind, :reverse_order, :lock, :create_with, :reordering, :from] + end + + def merge + normal_values.each do |name| + value = values[name] + relation.send("#{name}!", value) unless value.blank? + end + + merge_multi_values + merge_single_values + + relation + end + + private + + def merge_multi_values + relation.where_values = merged_wheres + relation.bind_values = merged_binds + + if values[:reordering] + # override any order specified in the original relation + relation.reorder! values[:order] + elsif values[:order] + # merge in order_values from r + relation.order! values[:order] + end + + relation.extend(*values[:extending]) unless values[:extending].blank? + end + + def merge_single_values + relation.from_value = values[:from] unless relation.from_value + relation.lock_value = values[:lock] unless relation.lock_value + relation.reverse_order_value = values[:reverse_order] + + unless values[:create_with].blank? + relation.create_with_value = (relation.create_with_value || {}).merge(values[:create_with]) + end + end + + def merged_binds + if values[:bind] + (relation.bind_values + values[:bind]).uniq(&:first) + else + relation.bind_values + end + end + + def merged_wheres + if values[:where] + merged_wheres = relation.where_values + values[:where] + + unless relation.where_values.empty? + # Remove equalities with duplicated left-hand. Last one wins. + seen = {} + merged_wheres = merged_wheres.reverse.reject { |w| + nuke = false + if w.respond_to?(:operator) && w.operator == :== + nuke = seen[w.left] + seen[w.left] = true + end + nuke + }.reverse + end + + merged_wheres + else + relation.where_values + end + end + end + end +end diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb index 1d04e763f6..cb8f903474 100644 --- a/activerecord/lib/active_record/relation/predicate_builder.rb +++ b/activerecord/lib/active_record/relation/predicate_builder.rb @@ -1,12 +1,12 @@ module ActiveRecord class PredicateBuilder # :nodoc: def self.build_from_hash(engine, attributes, default_table) - predicates = attributes.map do |column, value| + attributes.map do |column, value| table = default_table if value.is_a?(Hash) table = Arel::Table.new(column, engine) - build_from_hash(engine, value, table) + value.map { |k,v| build(table[k.to_sym], v) } else column = column.to_s @@ -17,50 +17,49 @@ module ActiveRecord build(table[column.to_sym], value) end - end - predicates.flatten + end.flatten end def self.references(attributes) - references = attributes.map do |key, value| + attributes.map do |key, value| if value.is_a?(Hash) key else key = key.to_s key.split('.').first.to_sym if key.include?('.') end - end - references.compact + end.compact end private def self.build(attribute, value) case value - when ActiveRecord::Relation - value = value.select(value.klass.arel_table[value.klass.primary_key]) if value.select_values.empty? - attribute.in(value.arel.ast) when Array, ActiveRecord::Associations::CollectionProxy values = value.to_a.map {|x| x.is_a?(ActiveRecord::Model) ? x.id : x} - ranges, values = values.partition {|v| v.is_a?(Range) || v.is_a?(Arel::Relation)} + ranges, values = values.partition {|v| v.is_a?(Range)} - array_predicates = ranges.map {|range| attribute.in(range)} - - if values.include?(nil) + values_predicate = if values.include?(nil) values = values.compact + case values.length when 0 - array_predicates << attribute.eq(nil) + attribute.eq(nil) when 1 - array_predicates << attribute.eq(values.first).or(attribute.eq(nil)) + attribute.eq(values.first).or(attribute.eq(nil)) else - array_predicates << attribute.in(values).or(attribute.eq(nil)) + attribute.in(values).or(attribute.eq(nil)) end else - array_predicates << attribute.in(values) + attribute.in(values) end - array_predicates.inject {|composite, predicate| composite.or(predicate)} - when Range, Arel::Relation + array_predicates = ranges.map { |range| attribute.in(range) } + array_predicates << values_predicate + array_predicates.inject { |composite, predicate| composite.or(predicate) } + when ActiveRecord::Relation + value = value.select(value.klass.arel_table[value.klass.primary_key]) if value.select_values.empty? + attribute.in(value.arel.ast) + when Range attribute.in(value) when ActiveRecord::Model attribute.eq(value.id) diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb index b6d762c2e2..f6bacf4822 100644 --- a/activerecord/lib/active_record/relation/query_methods.rb +++ b/activerecord/lib/active_record/relation/query_methods.rb @@ -1,66 +1,134 @@ require 'active_support/core_ext/array/wrap' -require 'active_support/core_ext/object/blank' 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, :reordering_value, :reverse_order_value, - :uniq_value, :references_values + 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) + raise ImmutableRelation if @loaded # raise ImmutableRelation if @loaded + @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 + CODE + end + + Relation::SINGLE_VALUE_METHODS.each do |name| + class_eval <<-CODE, __FILE__, __LINE__ + 1 + def #{name}_value=(value) # def readonly_value=(value) + raise ImmutableRelation if @loaded # raise ImmutableRelation if @loaded + @values[:#{name}] = value # @values[:readonly] = value + end # end + CODE + end + def create_with_value # :nodoc: + @values[:create_with] || {} + end + + alias extensions extending_values + + # Specify relationships to be included in the result set. For + # example: + # + # users = User.includes(:address) + # users.each do |user| + # user.address.city + # end + # + # allows you to access the +address+ attribute of the +User+ model without + # firing an additional query. This will often result in a + # performance improvement over a simple +join+. + # + # === conditions + # + # If you want to add conditions to your included models you'll have + # to explicitly reference them. For example: + # + # User.includes(:posts).where('posts.name = ?', 'example') + # + # Will throw an error, but this will work: + # + # User.includes(:posts).where('posts.name = ?', 'example').references(:posts) def includes(*args) - args.reject! {|a| a.blank? } + args.empty? ? self : spawn.includes!(*args) + end - return self if args.empty? + # Like #includes, but modifies the relation in place. + 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 + # Forces eager loading by performing a LEFT OUTER JOIN on +args+: + # + # User.eager_load(:posts) + # => SELECT "users"."id" AS t0_r0, "users"."name" AS t0_r1, ... + # FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" = + # "users"."id" 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 + # Like #eager_load, but modifies relation in place. + def eager_load!(*args) + self.eager_load_values += args + self end + # Allows preloading of +args+, in the same way that +includes+ does: + # + # User.preload(:posts) + # => SELECT "posts".* FROM "posts" WHERE "posts"."user_id" IN (1, 2, 3) def preload(*args) - return self if args.blank? + args.blank? ? self : spawn.preload!(*args) + end - relation = clone - relation.preload_values += args - relation + # Like #preload, but modifies relation in place. + def preload!(*args) + self.preload_values += args + self end # 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) - return self if args.blank? + args.blank? ? self : spawn.references!(*args) + end + + # Like #references, but modifies relation in place. + def references!(*args) + args.flatten! - relation = clone - relation.references_values = (references_values + args.flatten.map(&:to_s)).uniq - relation + self.references_values = (references_values + args.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 } + # Model.all.select { |m| m.field == value } # # This will build an array of objects from the database for the scope, # converting them into an array and iterating through them using Array#select. @@ -68,8 +136,8 @@ module ActiveRecord # Second: Modifies the SELECT statement for the query so that only certain # fields are retrieved: # - # >> Model.select(:field) - # => [#<Model field:value>] + # Model.select(:field) + # # => [#<Model field:value>] # # Although in the above example it looks as though this method returns an # array, it actually returns a relation object and can have other query @@ -77,44 +145,77 @@ module ActiveRecord # # The argument to the method can also be an array of fields. # - # >> Model.select([:field, :other_field, :and_one_more]) - # => [#<Model field: "value", other_field: "value", and_one_more: "value">] + # Model.select(:field, :other_field, :and_one_more) + # # => [#<Model field: "value", other_field: "value", and_one_more: "value">] # # 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 - # => ActiveModel::MissingAttributeError: missing attribute: other_field - def select(value = Proc.new) + # Model.select(:field).first.other_field + # # => ActiveModel::MissingAttributeError: missing attribute: other_field + def select(*fields) if block_given? - to_a.select {|*block_args| value.call(*block_args) } + to_a.select { |*block_args| yield(*block_args) } else - relation = clone - relation.select_values += Array.wrap(value) - relation + raise ArgumentError, 'Call this with at least one field' if fields.empty? + spawn.select!(*fields) end end + # Like #select, but modifies relation in place. + def select!(*fields) + self.select_values += fields.flatten + self + end + + # Allows to specify a group attribute: + # + # User.group(:name) + # => SELECT "users".* FROM "users" GROUP BY name + # + # Returns an array with distinct records based on the +group+ attribute: + # + # User.select([:id, :name]) + # => [#<User id: 1, name: "Oscar">, #<User id: 2, name: "Oscar">, #<User id: 3, name: "Foo"> + # + # User.group(:name) + # => [#<User id: 3, name: "Foo", ...>, #<User id: 2, name: "Oscar", ...>] def group(*args) - return self if args.blank? + args.blank? ? self : spawn.group!(*args) + end + + # Like #group, but modifies relation in place. + def group!(*args) + args.flatten! - relation = clone - relation.group_values += args.flatten - relation + self.group_values += args + self end + # Allows to specify an order attribute: + # + # User.order('name') + # => SELECT "users".* FROM "users" ORDER BY name + # + # User.order('name DESC') + # => SELECT "users".* FROM "users" ORDER BY name DESC + # + # User.order('name DESC, email') + # => SELECT "users".* FROM "users" ORDER BY name DESC, email def order(*args) - return self if args.blank? + args.blank? ? self : spawn.order!(*args) + end + + # Like #order, but modifies relation in place. + def order!(*args) + args.flatten! - args = args.flatten references = args.reject { |arg| Arel::Node === arg } - .map { |arg| arg =~ /^([a-zA-Z]\w*)\.(\w+)/ && $1 } - .compact + references.map! { |arg| arg =~ /^([a-zA-Z]\w*)\.(\w+)/ && $1 }.compact! + references!(references) if references.any? - relation = clone - relation = relation.references(references) if references.any? - relation.order_values += args - relation + self.order_values = args + self.order_values + self end # Replaces any existing order defined on the relation with the specified order. @@ -125,89 +226,226 @@ module ActiveRecord # # User.order('email DESC').reorder('id ASC').order('name ASC') # - # generates a query with 'ORDER BY id ASC, name ASC'. - # + # generates a query with 'ORDER BY name ASC, id ASC'. def reorder(*args) - return self if args.blank? + args.blank? ? self : spawn.reorder!(*args) + end - relation = clone - relation.reordering_value = true - relation.order_values = args.flatten - relation + # Like #reorder, but modifies relation in place. + def reorder!(*args) + args.flatten! + + self.reordering_value = true + self.order_values = args + self end + # Performs a joins on +args+: + # + # User.joins(:posts) + # => SELECT "users".* FROM "users" INNER JOIN "posts" ON "posts"."user_id" = "users"."id" def joins(*args) - return self if args.compact.blank? - - relation = clone + args.compact.blank? ? self : spawn.joins!(*args) + end + # Like #joins, but modifies relation in place. + 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 + # Returns a new relation, which is the result of filtering the current relation + # according to the conditions in the arguments. + # + # #where accepts conditions in one of several formats. In the examples below, the resulting + # SQL is given as an illustration; the actual query generated may be different depending + # on the database adapter. + # + # === string + # + # A single string, without additional arguments, is passed to the query + # constructor as a SQL fragment, and used in the where clause of the query. + # + # Client.where("orders_count = '2'") + # # SELECT * from clients where orders_count = '2'; + # + # Note that building your own string from user input may expose your application + # to injection attacks if not done properly. As an alternative, it is recommended + # to use one of the following methods. + # + # === array + # + # If an array is passed, then the first element of the array is treated as a template, and + # the remaining elements are inserted into the template to generate the condition. + # Active Record takes care of building the query to avoid injection attacks, and will + # convert from the ruby type to the database type where needed. Elements are inserted + # into the string in the order in which they appear. + # + # User.where(["name = ? and email = ?", "Joe", "joe@example.com"]) + # # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com'; + # + # Alternatively, you can use named placeholders in the template, and pass a hash as the + # second element of the array. The names in the template are replaced with the corresponding + # values from the hash. + # + # User.where(["name = :name and email = :email", { name: "Joe", email: "joe@example.com" }]) + # # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com'; + # + # This can make for more readable code in complex queries. + # + # Lastly, you can use sprintf-style % escapes in the template. This works slightly differently + # than the previous methods; you are responsible for ensuring that the values in the template + # are properly quoted. The values are passed to the connector for quoting, but the caller + # is responsible for ensuring they are enclosed in quotes in the resulting SQL. After quoting, + # the values are inserted using the same escapes as the Ruby core method <tt>Kernel::sprintf</tt>. + # + # User.where(["name = '%s' and email = '%s'", "Joe", "joe@example.com"]) + # # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com'; + # + # If #where is called with multiple arguments, these are treated as if they were passed as + # the elements of a single array. + # + # User.where("name = :name and email = :email", { name: "Joe", email: "joe@example.com" }) + # # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com'; + # + # When using strings to specify conditions, you can use any operator available from + # the database. While this provides the most flexibility, you can also unintentionally introduce + # dependencies on the underlying database. If your code is intended for general consumption, + # test with multiple database backends. + # + # === hash + # + # #where will also accept a hash condition, in which the keys are fields and the values + # are values to be searched for. + # + # Fields can be symbols or strings. Values can be single values, arrays, or ranges. + # + # User.where({ name: "Joe", email: "joe@example.com" }) + # # SELECT * FROM users WHERE name = 'Joe' AND email = 'joe@example.com' + # + # User.where({ name: ["Alice", "Bob"]}) + # # SELECT * FROM users WHERE name IN ('Alice', 'Bob') + # + # User.where({ created_at: (Time.now.midnight - 1.day)..Time.now.midnight }) + # # SELECT * FROM users WHERE (created_at BETWEEN '2012-06-09 07:00:00.000000' AND '2012-06-10 07:00:00.000000') + # + # === Joins + # + # If the relation is the result of a join, you may create a condition which uses any of the + # tables in the join. For string and array conditions, use the table name in the condition. + # + # User.joins(:posts).where("posts.created_at < ?", Time.now) + # + # For hash conditions, you can either use the table name in the key, or use a sub-hash. + # + # User.joins(:posts).where({ "posts.published" => true }) + # User.joins(:posts).where({ :posts => { :published => true } }) + # + # === empty condition + # + # If the condition returns true for blank?, then where is a no-op and returns the current relation. def where(opts, *rest) - return self if opts.blank? + opts.blank? ? self : spawn.where!(opts, *rest) + end - relation = clone - relation = relation.references(PredicateBuilder.references(opts)) if Hash === opts - relation.where_values += build_where(opts, rest) - relation + # #where! is identical to #where, except that instead of returning a new relation, it adds + # the condition to the existing relation. + def where!(opts, *rest) + references!(PredicateBuilder.references(opts)) if Hash === opts + + self.where_values += build_where(opts, rest) + self end + # Allows to specify a HAVING clause. Note that you can't use HAVING + # without also specifying a GROUP clause. + # + # Order.having('SUM(price) > 30').group('user_id') def having(opts, *rest) - return self if opts.blank? + opts.blank? ? self : spawn.having!(opts, *rest) + end + + # Like #having, but modifies relation in place. + def having!(opts, *rest) + references!(PredicateBuilder.references(opts)) if Hash === opts - relation = clone - relation = relation.references(PredicateBuilder.references(opts)) if Hash === opts - relation.having_values += build_where(opts, rest) - relation + self.having_values += build_where(opts, rest) + self end + # Specifies a limit for the number of records to retrieve. + # + # User.limit(10) # generated SQL has 'LIMIT 10' + # + # User.limit(10).limit(20) # generated SQL has 'LIMIT 20' def limit(value) - relation = clone - relation.limit_value = value - relation + spawn.limit!(value) + end + + # Like #limit, but modifies relation in place. + def limit!(value) + self.limit_value = value + self end + # Specifies the number of rows to skip before returning rows. + # + # User.offset(10) # generated SQL has "OFFSET 10" + # + # Should be used with order. + # + # User.offset(10).order("name ASC") def offset(value) - relation = clone - relation.offset_value = value - relation + spawn.offset!(value) + end + + # Like #offset, but modifies relation in place. + def offset!(value) + self.offset_value = value + self end + # Specifies locking settings (default to +true+). For more information + # on locking, please see +ActiveRecord::Locking+. def lock(locks = true) - relation = clone + spawn.lock!(locks) + end + # Like #lock, but modifies relation in place. + 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. + # instance of the <tt>ActiveRecord::NullRelation</tt> 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. + # The returned <tt>ActiveRecord::NullRelation</tt> inherits from Relation and implements the + # Null Object pattern. It is an object with defined null behavior and always returns an empty + # array of records without quering 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. # - # This is useful in scenarios where you need a chainable response to a method - # or a scope that could return zero results. + # Used in cases where a method or scope could return zero records but the + # result needs to be chainable. # # For example: # @@ -226,25 +464,73 @@ module ActiveRecord # end # def none - NullRelation.new(@klass, @table) + extending(NullRelation) end + # Sets readonly attributes for the returned relation. If value is + # true (default), attempting to update a record will result in an error. + # + # users = User.readonly + # users.first.save + # => ActiveRecord::ReadOnlyRecord: ActiveRecord::ReadOnlyRecord def readonly(value = true) - relation = clone - relation.readonly_value = value - relation + spawn.readonly!(value) end + # Like #readonly, but modifies relation in place. + def readonly!(value = true) + self.readonly_value = value + self + end + + # Sets attributes to be used when creating new records from a + # relation object. + # + # users = User.where(name: 'Oscar') + # users.new.name # => 'Oscar' + # + # users = users.create_with(name: 'DHH') + # users.new.name # => 'DHH' + # + # You can pass +nil+ to +create_with+ to reset attributes: + # + # users = users.create_with(nil) + # users.new.name # => 'Oscar' def create_with(value) - relation = clone - relation.create_with_value = value ? create_with_value.merge(value) : {} - relation + spawn.create_with!(value) + end + + # Like #create_with but modifies the relation in place. Raises + # +ImmutableRelation+ if the relation has already been loaded. + # + # users = User.all.create_with!(name: 'Oscar') + # users.new.name # => 'Oscar' + def create_with!(value) + self.create_with_value = value ? create_with_value.merge(value) : {} + self end - def from(value) - relation = clone - relation.from_value = value - relation + # 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(Topic.approved) + # # => SELECT title FROM (SELECT * FROM topics WHERE approved = 't') subquery + # + # Topic.select('a.title').from(Topic.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 + + # Like #from, but modifies relation in place. + 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: @@ -258,9 +544,13 @@ module ActiveRecord # User.select(:name).uniq.uniq(false) # # => You can also remove the uniqueness def uniq(value = true) - relation = clone - relation.uniq_value = value - relation + spawn.uniq!(value) + end + + # Like #uniq, but modifies relation in place. + def uniq!(value = true) + self.uniq_value = value + self end # Used to extend a scope with additional methods, either through @@ -276,16 +566,16 @@ module ActiveRecord # end # end # - # scope = Model.scoped.extending(Pagination) + # scope = Model.all.extending(Pagination) # scope.page(params[:page]) # # You can also pass a list of modules: # - # scope = Model.scoped.extending(Pagination, SomethingElse) + # scope = Model.all.extending(Pagination, SomethingElse) # # === Using a block # - # scope = Model.scoped.extending do + # scope = Model.all.extending do # def page(number) # # pagination code goes here # end @@ -294,54 +584,71 @@ module ActiveRecord # # You can also use a block and a module list: # - # scope = Model.scoped.extending(Pagination) do + # scope = Model.all.extending(Pagination) do # def per_page(number) # # 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? + # Like #extending, but modifies relation in place. + 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 + # Reverse the existing order clause on the relation. + # + # User.order('name ASC').reverse_order # generated SQL has 'ORDER BY name DESC' def reverse_order - relation = clone - relation.reverse_order_value = !relation.reverse_order_value - relation + spawn.reverse_order! + end + + # Like #reverse_order, but modifies relation in place. + def reverse_order! + self.reverse_order_value = !reverse_order_value + self end + # Returns the Arel object associated with the relation. def arel @arel ||= with_default_scope.build_arel end + # Like #arel, but ignores the default scope of the model. def build_arel - arel = table.from table + arel = Arel::SelectManager.new(table.engine, 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 = @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.distinct(@uniq_value) - 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 @@ -389,6 +696,17 @@ 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 @@ -443,13 +761,6 @@ 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? diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb index 7131aa29b6..5394c1b28b 100644 --- a/activerecord/lib/active_record/relation/spawn_methods.rb +++ b/activerecord/lib/active_record/relation/spawn_methods.rb @@ -1,75 +1,53 @@ -require 'active_support/core_ext/object/blank' +require 'active_support/core_ext/hash/except' +require 'active_support/core_ext/hash/slice' +require 'active_record/relation/merger' module ActiveRecord module SpawnMethods - def merge(r) - return self unless r - return to_a & r if r.is_a?(Array) - merged_relation = clone - - r = r.with_default_scope if r.default_scoped? && r.klass != klass - - Relation::ASSOCIATION_METHODS.each do |method| - value = r.send(:"#{method}_values") - - unless value.empty? - if method == :includes - merged_relation = merged_relation.includes(value) - else - merged_relation.send(:"#{method}_values=", value) - end - end - end - - (Relation::MULTI_VALUE_METHODS - [:joins, :where, :order]).each do |method| - value = r.send(:"#{method}_values") - merged_relation.send(:"#{method}_values=", merged_relation.send(:"#{method}_values") + value) if value.present? - end - - merged_relation.joins_values += r.joins_values - - merged_wheres = @where_values + r.where_values - - unless @where_values.empty? - # Remove duplicates, last one wins. - seen = Hash.new { |h,table| h[table] = {} } - merged_wheres = merged_wheres.reverse.reject { |w| - nuke = false - if w.respond_to?(:operator) && w.operator == :== - name = w.left.name - table = w.left.relation.name - nuke = seen[table][name] - seen[table][name] = true - end - nuke - }.reverse - end - - merged_relation.where_values = merged_wheres + # This is overridden by Associations::CollectionProxy + def spawn #:nodoc: + clone + end - (Relation::SINGLE_VALUE_METHODS - [:lock, :create_with, :reordering]).each do |method| - value = r.send(:"#{method}_value") - merged_relation.send(:"#{method}_value=", value) unless value.nil? + # Merges in the conditions from <tt>other</tt>, if <tt>other</tt> is an <tt>ActiveRecord::Relation</tt>. + # Returns an array representing the intersection of the resulting records with <tt>other</tt>, if <tt>other</tt> is an array. + # + # ==== Examples + # + # Post.where(:published => true).joins(:comments).merge( Comment.where(:spam => false) ) + # # Performs a single join query with both where conditions. + # + # recent_posts = Post.order('created_at DESC').first(5) + # Post.where(:published => true).merge(recent_posts) + # # Returns the intersection of all published posts with the 5 most recently created posts. + # # (This is just an example. You'd probably want to do this with a single query!) + # + # Procs will be evaluated by merge: + # + # Post.where(published: true).merge(-> { joins(:comments) }) + # # => Post.where(published: true).joins(:comments) + # + # This is mainly intended for sharing common conditions between multiple associations. + # + def merge(other) + if other.is_a?(Array) + to_a & other + elsif other + spawn.merge!(other) + else + self end + end - merged_relation.lock_value = r.lock_value unless merged_relation.lock_value - - merged_relation = merged_relation.create_with(r.create_with_value) unless r.create_with_value.empty? - - if (r.reordering_value) - # override any order specified in the original relation - merged_relation.reordering_value = true - merged_relation.order_values = r.order_values + # Like #merge, but applies changes in place. + def merge!(other) + if !other.is_a?(Relation) && other.respond_to?(:to_proc) + instance_exec(&other) else - # merge in order_values from r - merged_relation.order_values += r.order_values + klass = other.is_a?(Hash) ? Relation::HashMerger : Relation::Merger + klass.new(self, other).merge end - - # Apply scope extension modules - merged_relation.send :apply_modules, r.extensions - - merged_relation end # Removes from the query the condition(s) specified in +skips+. @@ -80,20 +58,9 @@ module ActiveRecord # Post.where('id > 10').order('id asc').except(:where) # discards the where condition but keeps the order # def except(*skips) - result = self.class.new(@klass, table) + result = Relation.new(klass, table, values.except(*skips)) result.default_scoped = default_scoped - - ((Relation::ASSOCIATION_METHODS + Relation::MULTI_VALUE_METHODS) - skips).each do |method| - result.send(:"#{method}_values=", send(:"#{method}_values")) - end - - (Relation::SINGLE_VALUE_METHODS - skips).each do |method| - result.send(:"#{method}_value=", send(:"#{method}_value")) - end - - # Apply scope extension modules - result.send(:apply_modules, extensions) - + result.extend(*extending_values) if extending_values.any? result end @@ -105,44 +72,11 @@ module ActiveRecord # Post.order('id asc').only(:where, :order) # uses the specified order # def only(*onlies) - result = self.class.new(@klass, table) + result = Relation.new(klass, table, values.slice(*onlies)) result.default_scoped = default_scoped - - ((Relation::ASSOCIATION_METHODS + Relation::MULTI_VALUE_METHODS) & onlies).each do |method| - result.send(:"#{method}_values=", send(:"#{method}_values")) - end - - (Relation::SINGLE_VALUE_METHODS & onlies).each do |method| - result.send(:"#{method}_value=", send(:"#{method}_value")) - end - - # Apply scope extension modules - result.send(:apply_modules, extensions) - + result.extend(*extending_values) if extending_values.any? result end - VALID_FIND_OPTIONS = [ :conditions, :include, :joins, :limit, :offset, :extend, :references, - :order, :select, :readonly, :group, :having, :from, :lock ] - - def apply_finder_options(options) - relation = clone - return relation unless options - - options.assert_valid_keys(VALID_FIND_OPTIONS) - finders = options.dup - finders.delete_if { |key, value| value.nil? && key != :limit } - - ((VALID_FIND_OPTIONS - [:conditions, :include, :extend]) & finders.keys).each do |finder| - relation = relation.send(finder, finders[finder]) - end - - relation = relation.where(finders[:conditions]) if options.has_key?(:conditions) - relation = relation.includes(finders[:include]) if options.has_key?(:include) - relation = relation.extending(finders[:extend]) if options.has_key?(:extend) - - relation - end - end end |