diff options
Diffstat (limited to 'activerecord/lib/active_record/relation/query_methods.rb')
| -rw-r--r-- | activerecord/lib/active_record/relation/query_methods.rb | 306 |
1 files changed, 262 insertions, 44 deletions
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb index a89d0f3ebf..8e6254f918 100644 --- a/activerecord/lib/active_record/relation/query_methods.rb +++ b/activerecord/lib/active_record/relation/query_methods.rb @@ -1,5 +1,4 @@ require 'active_support/core_ext/array/wrap' -require 'active_support/core_ext/object/blank' module ActiveRecord module QueryMethods @@ -7,42 +6,67 @@ module ActiveRecord 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 + 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 - # - def #{name}_value=(value) # def readonly_value=(value) - @values[:#{name}] = value # @values[:readonly] = value - end # end + def #{name}_value # def readonly_value + @values[:#{name}] # @values[:readonly] + end # end CODE end - def create_with_value - @values[:create_with] || {} + 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=(value) - @values[:create_with] = value + 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.empty? ? self : spawn.includes!(*args) end + # Like #includes, but modifies the relation in place. def includes!(*args) args.reject! {|a| a.blank? } @@ -50,19 +74,31 @@ module ActiveRecord 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) args.blank? ? self : spawn.eager_load!(*args) end + # 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) args.blank? ? self : spawn.preload!(*args) end + # Like #preload, but modifies relation in place. def preload!(*args) self.preload_values += args self @@ -71,8 +107,6 @@ module ActiveRecord # 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. # @@ -82,8 +116,11 @@ module ActiveRecord args.blank? ? self : spawn.references!(*args) end + # Like #references, but modifies relation in place. def references!(*args) - self.references_values = (references_values + args.flatten.map(&:to_s)).uniq + args.flatten! + + self.references_values = (references_values + args.map!(&:to_s)).uniq self end @@ -91,7 +128,7 @@ module ActiveRecord # # 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. @@ -124,33 +161,59 @@ module ActiveRecord end end + # Like #select, but modifies relation in place. def select!(value) self.select_values += Array.wrap(value) 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) args.blank? ? self : spawn.group!(*args) end + # Like #group, but modifies relation in place. def group!(*args) - self.group_values += args.flatten + args.flatten! + + 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) args.blank? ? self : spawn.order!(*args) end + # Like #order, but modifies relation in place. def order!(*args) - args = args.flatten + 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? - self.order_values += args + self.order_values = args + self.order_values self end @@ -162,22 +225,29 @@ 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) args.blank? ? self : spawn.reorder!(*args) end + # Like #reorder, but modifies relation in place. def reorder!(*args) + args.flatten! + self.reordering_value = true - self.order_values = args.flatten + 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) args.compact.blank? ? self : spawn.joins!(*args) end + # Like #joins, but modifies relation in place. def joins!(*args) args.flatten! @@ -194,10 +264,102 @@ module ActiveRecord 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) opts.blank? ? self : spawn.where!(opts, *rest) end + # #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 @@ -205,10 +367,15 @@ module ActiveRecord 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) 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 @@ -216,28 +383,45 @@ module ActiveRecord 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) 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) 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) spawn.lock!(locks) end + # Like #lock, but modifies relation in place. def lock!(locks = true) case locks when String, TrueClass, NilClass @@ -250,11 +434,11 @@ module ActiveRecord 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. @@ -279,22 +463,47 @@ module ActiveRecord # end # def none - scoped.extending(NullRelation) + 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) 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) 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 @@ -307,16 +516,17 @@ module ActiveRecord # # Can accept other relation objects. For example: # - # Topic.select('title').from(Topics.approved) + # Topic.select('title').from(Topic.approved) # # => SELECT title FROM (SELECT * FROM topics WHERE approved = 't') subquery # - # Topics.select('a.title').from(Topics.approved, :a) + # 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 @@ -336,6 +546,7 @@ module ActiveRecord spawn.uniq!(value) end + # Like #uniq, but modifies relation in place. def uniq!(value = true) self.uniq_value = value self @@ -354,16 +565,16 @@ 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 @@ -372,7 +583,7 @@ 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 @@ -385,30 +596,37 @@ module ActiveRecord end end + # Like #extending, but modifies relation in place. def extending!(*modules, &block) modules << Module.new(&block) if block_given? - self.extending_values = modules.flatten + 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 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? |