module ActiveRecord::QueryMethods
Constants
- FROZEN_EMPTY_ARRAY
- FROZEN_EMPTY_HASH
- VALID_UNSCOPING_VALUES
Public Instance Methods
Returns a new relation, which is the logical intersection of this relation and the one passed as an argument.
The two relations must be structurally compatible: they must be scoping the same model, and they must differ only by where
(if no group
has been defined) or having
(if a group
is present).
Post.where(id: [1, 2]).and(Post.where(id: [2, 3])) # SELECT `posts`.* FROM `posts` WHERE `posts`.`id` IN (1, 2) AND `posts`.`id` IN (2, 3)
# File lib/active_record/relation/query_methods.rb, line 681 def and(other) if other.is_a?(Relation) spawn.and!(other) else raise ArgumentError, "You have passed #{other.class.name} object to #and. Pass an ActiveRecord::Relation object instead." end end
Adds an SQL comment to queries generated from this relation. For example:
User.annotate("selecting user names").select(:name) # SELECT "users"."name" FROM "users" /* selecting user names */ User.annotate("selecting", "user", "names").select(:name) # SELECT "users"."name" FROM "users" /* selecting */ /* user */ /* names */
The SQL block comment delimiters, “/*” and “*/”, will be added automatically.
Some escaping is performed, however untrusted user input should not be used.
# File lib/active_record/relation/query_methods.rb, line 1040 def annotate(*args) check_if_method_has_arguments!(:annotate, args) spawn.annotate!(*args) 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'
# File lib/active_record/relation/query_methods.rb, line 874 def create_with(value) spawn.create_with!(value) end
Specifies whether the records should be unique or not. For example:
User.select(:name) # Might return two records with the same name User.select(:name).distinct # Returns 1 record per distinct name User.select(:name).distinct.distinct(false) # You can also remove the uniqueness
# File lib/active_record/relation/query_methods.rb, line 921 def distinct(value = true) spawn.distinct!(value) 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"
# File lib/active_record/relation/query_methods.rb, line 166 def eager_load(*args) check_if_method_has_arguments!(:eager_load, args) spawn.eager_load!(*args) end
Used to extend a scope with additional methods, either through a module or through a block provided.
The object returned is a relation, which can be further extended.
Using a module¶ ↑
module Pagination def page(number) # pagination code goes here end end scope = Model.all.extending(Pagination) scope.page(params[:page])
You can also pass a list of modules:
scope = Model.all.extending(Pagination, SomethingElse)
Using a block¶ ↑
scope = Model.all.extending do def page(number) # pagination code goes here end end scope.page(params[:page])
You can also use a block and a module list:
scope = Model.all.extending(Pagination) do def per_page(number) # pagination code goes here end end
# File lib/active_record/relation/query_methods.rb, line 967 def extending(*modules, &block) if modules.any? || block spawn.extending!(*modules, &block) else self end end
Extracts a named association
from the relation. The named association is first preloaded, then the individual association records are collected from the relation. Like so:
account.memberships.extract_associated(:user) # => Returns collection of User records
This is short-hand for:
account.memberships.preload(:user).collect(&:user)
# File lib/active_record/relation/query_methods.rb, line 199 def extract_associated(association) preload(association).collect(&association) end
Specifies table from which the records will be fetched. For example:
Topic.select('title').from('posts') # SELECT title FROM posts
Can accept other relation objects. For example:
Topic.select('title').from(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
# File lib/active_record/relation/query_methods.rb, line 902 def from(value, subquery_name = nil) spawn.from!(value, subquery_name) 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", ...>] User.group('name AS grouped_name, age') # => [#<User id: 3, name: "Foo", age: 21, ...>, #<User id: 2, name: "Oscar", age: 21, ...>, #<User id: 5, name: "Foo", age: 23, ...>]
Passing in an array of attributes to group by is also supported.
User.select([:id, :first_name]).group(:id, :first_name).first(3) # => [#<User id: 1, first_name: "Bill">, #<User id: 2, first_name: "Earl">, #<User id: 3, first_name: "Beto">]
# File lib/active_record/relation/query_methods.rb, line 322 def group(*args) check_if_method_has_arguments!(:group, args) spawn.group!(*args) 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')
# File lib/active_record/relation/query_methods.rb, line 739 def having(opts, *rest) opts.blank? ? self : spawn.having!(opts, *rest) end
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.
You can also specify multiple relationships, like this:
users = User.includes(:address, :friends)
Loading nested relationships is possible using a Hash:
users = User.includes(:address, friends: [:address, :followers])
conditions¶ ↑
If you want to add string 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)
Note that includes
works with association names while references
needs the actual table name.
If you pass the conditions via hash, you don't need to call references
explicitly, as where
references the tables for you. For example, this will work correctly:
User.includes(:posts).where(posts: { name: 'example' })
# File lib/active_record/relation/query_methods.rb, line 150 def includes(*args) check_if_method_has_arguments!(:includes, args) spawn.includes!(*args) end
Performs a joins on args
. The given symbol(s) should match the name of the association(s).
User.joins(:posts) # SELECT "users".* # FROM "users" # INNER JOIN "posts" ON "posts"."user_id" = "users"."id"
Multiple joins:
User.joins(:posts, :account) # SELECT "users".* # FROM "users" # INNER JOIN "posts" ON "posts"."user_id" = "users"."id" # INNER JOIN "accounts" ON "accounts"."id" = "users"."account_id"
Nested joins:
User.joins(posts: [:comments]) # SELECT "users".* # FROM "users" # INNER JOIN "posts" ON "posts"."user_id" = "users"."id" # INNER JOIN "comments" ON "comments"."post_id" = "posts"."id"
You can use strings in order to customize your joins:
User.joins("LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id = users.id") # SELECT "users".* FROM "users" LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id = users.id
# File lib/active_record/relation/query_methods.rb, line 489 def joins(*args) check_if_method_has_arguments!(:joins, args) spawn.joins!(*args) end
Performs a left outer joins on args
:
User.left_outer_joins(:posts) => SELECT "users".* FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" = "users"."id"
# File lib/active_record/relation/query_methods.rb, line 504 def left_outer_joins(*args) check_if_method_has_arguments!(__callee__, args) spawn.left_outer_joins!(*args) 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'
# File lib/active_record/relation/query_methods.rb, line 753 def limit(value) spawn.limit!(value) end
Specifies locking settings (default to true
). For more information on locking, please see ActiveRecord::Locking
.
# File lib/active_record/relation/query_methods.rb, line 780 def lock(locks = true) spawn.lock!(locks) end
Returns a chainable relation with zero records.
The returned relation implements the Null Object pattern. It is an object with defined null behavior and always returns an empty array of records without querying the database.
Any subsequent condition chained to the returned relation will continue generating an empty relation and will not fire any query to the database.
Used in cases where a method or scope could return zero records but the result needs to be chainable.
For example:
@posts = current_user.visible_posts.where(name: params[:name]) # the visible_posts method is expected to return a chainable Relation def visible_posts case role when 'Country Manager' Post.where(country: country) when 'Reviewer' Post.published when 'Bad User' Post.none # It can't be chained if [] is returned. end end
# File lib/active_record/relation/query_methods.rb, line 823 def none spawn.none! 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")
# File lib/active_record/relation/query_methods.rb, line 769 def offset(value) spawn.offset!(value) end
Specify optimizer hints to be used in the SELECT statement.
Example (for MySQL):
Topic.optimizer_hints("MAX_EXECUTION_TIME(50000)", "NO_INDEX_MERGE(topics)") # SELECT /*+ MAX_EXECUTION_TIME(50000) NO_INDEX_MERGE(topics) */ `topics`.* FROM `topics`
Example (for PostgreSQL with pg_hint_plan):
Topic.optimizer_hints("SeqScan(topics)", "Parallel(topics 8)") # SELECT /*+ SeqScan(topics) Parallel(topics 8) */ "topics".* FROM "topics"
# File lib/active_record/relation/query_methods.rb, line 996 def optimizer_hints(*args) check_if_method_has_arguments!(:optimizer_hints, args) spawn.optimizer_hints!(*args) end
Returns a new relation, which is the logical union of this relation and the one passed as an argument.
The two relations must be structurally compatible: they must be scoping the same model, and they must differ only by where
(if no group
has been defined) or having
(if a group
is present).
Post.where("id = 1").or(Post.where("author_id = 3")) # SELECT `posts`.* FROM `posts` WHERE ((id = 1) OR (author_id = 3))
# File lib/active_record/relation/query_methods.rb, line 713 def or(other) if other.is_a?(Relation) spawn.or!(other) else raise ArgumentError, "You have passed #{other.class.name} object to #or. Pass an ActiveRecord::Relation object instead." end end
Allows to specify an order attribute:
User.order(:name) # SELECT "users".* FROM "users" ORDER BY "users"."name" ASC User.order(email: :desc) # SELECT "users".* FROM "users" ORDER BY "users"."email" DESC User.order(:name, email: :desc) # SELECT "users".* FROM "users" ORDER BY "users"."name" ASC, "users"."email" DESC 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
# File lib/active_record/relation/query_methods.rb, line 351 def order(*args) check_if_method_has_arguments!(:order, args) do sanitize_order_arguments(args) end spawn.order!(*args) 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)
# File lib/active_record/relation/query_methods.rb, line 180 def preload(*args) check_if_method_has_arguments!(:preload, args) spawn.preload!(*args) 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: User is marked as readonly
# File lib/active_record/relation/query_methods.rb, line 837 def readonly(value = true) spawn.readonly!(value) end
Use to indicate that the given table_names
are referenced by an SQL string, and should therefore be JOINed in any query rather than loaded separately. This method only works in conjunction with includes
. See includes
for more details.
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
# File lib/active_record/relation/query_methods.rb, line 213 def references(*table_names) check_if_method_has_arguments!(:references, table_names) spawn.references!(*table_names) end
Replaces any existing order defined on the relation with the specified order.
User.order('email DESC').reorder('id ASC') # generated SQL has 'ORDER BY id ASC'
Subsequent calls to order on the same relation will be appended. For example:
User.order('email DESC').reorder('id ASC').order('name ASC')
generates a query with 'ORDER BY id ASC, name ASC'.
# File lib/active_record/relation/query_methods.rb, line 374 def reorder(*args) check_if_method_has_arguments!(:reorder, args) do sanitize_order_arguments(args) unless args.all?(&:blank?) end spawn.reorder!(*args) end
Allows you to change a previously set select statement.
Post.select(:title, :body) # SELECT `posts`.`title`, `posts`.`body` FROM `posts` Post.select(:title, :body).reselect(:created_at) # SELECT `posts`.`created_at` FROM `posts`
This is short-hand for unscope(:select).select(fields)
. Note that we're unscoping the entire select statement.
# File lib/active_record/relation/query_methods.rb, line 291 def reselect(*args) check_if_method_has_arguments!(:reselect, args) spawn.reselect!(*args) end
Reverse the existing order clause on the relation.
User.order('name ASC').reverse_order # generated SQL has 'ORDER BY name DESC'
# File lib/active_record/relation/query_methods.rb, line 1009 def reverse_order spawn.reverse_order! end
Allows you to change a previously set where condition for a given attribute, instead of appending to that condition.
Post.where(trashed: true).where(trashed: false) # WHERE `trashed` = 1 AND `trashed` = 0 Post.where(trashed: true).rewhere(trashed: false) # WHERE `trashed` = 0 Post.where(active: true).where(trashed: true).rewhere(trashed: false) # WHERE `active` = 1 AND `trashed` = 0
This is short-hand for unscope(where: conditions.keys).where(conditions)
. Note that unlike reorder, we're only unscoping the named conditions – not the entire where statement.
# File lib/active_record/relation/query_methods.rb, line 662 def rewhere(conditions) scope = spawn where_clause = scope.build_where_clause(conditions) scope.unscope!(where: where_clause.extract_attributes) scope.where_clause += where_clause scope end
Works in two unique ways.
First: takes a block so it can be used just like Array#select
.
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
.
Second: Modifies the SELECT statement for the query so that only certain fields are retrieved:
Model.select(:field) # => [#<Model id: nil, 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 methods appended to it, such as the other methods in ActiveRecord::QueryMethods
.
The argument to the method can also be an array of fields.
Model.select(:field, :other_field, :and_one_more) # => [#<Model id: nil, field: "value", other_field: "value", and_one_more: "value">]
You can also use one or more strings, which will be used unchanged as SELECT fields.
Model.select('field AS field_one', 'other_field AS field_two') # => [#<Model id: nil, field: "value", other_field: "value">]
If an alias was specified, it will be accessible from the resulting objects:
Model.select('field AS field_one').first.field_one # => "value"
Accessing attributes of an object that do not have fields retrieved by a select except id
will throw ActiveModel::MissingAttributeError:
Model.select(:field).first.other_field # => ActiveModel::MissingAttributeError: missing attribute: other_field
# File lib/active_record/relation/query_methods.rb, line 263 def select(*fields) if block_given? if fields.any? raise ArgumentError, "`select' with block doesn't take arguments." end return super() end check_if_method_has_arguments!(:select, fields, "Call `select' with at least one field.") spawn._select!(*fields) end
Sets the returned relation to strict_loading
mode. This will raise an error if the record tries to lazily load an association.
user = User.strict_loading.first user.comments.to_a => ActiveRecord::StrictLoadingViolationError
# File lib/active_record/relation/query_methods.rb, line 852 def strict_loading(value = true) spawn.strict_loading!(value) end
Deduplicate multiple values.
# File lib/active_record/relation/query_methods.rb, line 1052 def uniq!(name) if values = @values[name] values.uniq! if values.is_a?(Array) && !values.empty? end self end
Removes an unwanted relation that is already defined on a chain of relations. This is useful when passing around chains of relations and would like to modify the relations without reconstructing the entire chain.
User.order('email DESC').unscope(:order) == User.all
The method arguments are symbols which correspond to the names of the methods which should be unscoped. The valid arguments are given in VALID_UNSCOPING_VALUES
. The method can also be called with multiple arguments. For example:
User.order('email DESC').select('id').where(name: "John") .unscope(:order, :select, :where) == User.all
One can additionally pass a hash as an argument to unscope specific :where
values. This is done by passing a hash with a single key-value pair. The key should be :where
and the value should be the where value to unscope. For example:
User.where(name: "John", active: true).unscope(where: :name) == User.where(active: true)
This method is similar to except, but unlike except, it persists across merges:
User.order('email').merge(User.except(:order)) == User.order('email') User.order('email').merge(User.unscope(:order)) == User.all
This means it can be used in association definitions:
has_many :comments, -> { unscope(where: :trashed) }
# File lib/active_record/relation/query_methods.rb, line 427 def unscope(*args) check_if_method_has_arguments!(:unscope, args) spawn.unscope!(*args) 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 an 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 Kernel::sprintf
.
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')
In the case of a belongs_to relationship, an association key can be used to specify the model if an ActiveRecord
object is used as the value.
author = Author.find(1) # The following queries will be equivalent: Post.where(author: author) Post.where(author_id: author)
This also works with polymorphic belongs_to relationships:
treasure = Treasure.create(name: 'gold coins') treasure.price_estimates << PriceEstimate.create(price: 125) # The following queries will be equivalent: PriceEstimate.where(estimate_of: treasure) PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: treasure)
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 } })
no argument¶ ↑
If no argument is passed, where
returns a new instance of WhereChain
, that can be chained with not to return a new relation that negates the where clause.
User.where.not(name: "Jon") # SELECT * FROM users WHERE name != 'Jon'
See WhereChain
for more details on not.
blank condition¶ ↑
If the condition is any blank-ish object, then where
is a no-op and returns the current relation.
# File lib/active_record/relation/query_methods.rb, line 634 def where(*args) if args.empty? WhereChain.new(spawn) elsif args.length == 1 && args.first.blank? self else spawn.where!(*args) end end
Private Instance Methods
# File lib/active_record/relation/query_methods.rb, line 1311 def arel_column(field) field = klass.attribute_aliases[field] || field from = from_clause.name || from_clause.value if klass.columns_hash.key?(field) && (!from || table_name_matches?(from)) table[field] elsif field.match?(/\A\w+\.\w+\z/) table, column = field.split(".") predicate_builder.resolve_arel_attribute(table, column) do lookup_table_klass_from_join_dependencies(table) end else yield field end end
# File lib/active_record/relation/query_methods.rb, line 1294 def arel_columns(columns) columns.flat_map do |field| case field when Symbol arel_column(field.to_s) do |attr_name| connection.quote_table_name(attr_name) end when String arel_column(field, &:itself) when Proc field.call else field end end end
# File lib/active_record/relation/query_methods.rb, line 1133 def assert_mutability! raise ImmutableRelation if @loaded raise ImmutableRelation if defined?(@arel) && @arel end
# File lib/active_record/relation/query_methods.rb, line 1138 def build_arel(aliases = nil) arel = Arel::SelectManager.new(table) build_joins(arel.join_sources, aliases) arel.where(where_clause.ast) unless where_clause.empty? arel.having(having_clause.ast) unless having_clause.empty? arel.take(build_cast_value("LIMIT", connection.sanitize_limit(limit_value))) if limit_value arel.skip(build_cast_value("OFFSET", offset_value.to_i)) if offset_value arel.group(*arel_columns(group_values.uniq)) unless group_values.empty? build_order(arel) build_select(arel) arel.optimizer_hints(*optimizer_hints_values) unless optimizer_hints_values.empty? arel.distinct(distinct_value) arel.from(build_from) unless from_clause.empty? arel.lock(lock_value) if lock_value unless annotate_values.empty? annotates = annotate_values annotates = annotates.uniq if annotates.size > 1 unless annotates == annotate_values ActiveSupport::Deprecation.warn(<<-MSG.squish) Duplicated query annotations are no longer shown in queries in Rails 7.0. To migrate to Rails 7.0's behavior, use `uniq!(:annotate)` to deduplicate query annotations (`#{klass.name&.tableize || klass.table_name}.uniq!(:annotate)`). MSG annotates = annotate_values end arel.comment(*annotates) end arel end
# File lib/active_record/relation/query_methods.rb, line 1174 def build_cast_value(name, value) cast_value = ActiveModel::Attribute.with_cast_value(name, value, Type.default_value) Arel::Nodes::BindParam.new(cast_value) end
# File lib/active_record/relation/query_methods.rb, line 1179 def build_from opts = from_clause.value name = from_clause.name case opts when Relation if opts.eager_loading? opts = opts.send(:apply_join_dependency) end name ||= "subquery" opts.arel.as(name.to_s) else opts end end
# File lib/active_record/relation/query_methods.rb, line 1212 def build_join_buckets buckets = Hash.new { |h, k| h[k] = [] } unless left_outer_joins_values.empty? stashed_left_joins = [] left_joins = select_association_list(left_outer_joins_values, stashed_left_joins) do raise ArgumentError, "only Hash, Symbol and Array are allowed" end if joins_values.empty? buckets[:association_join] = left_joins buckets[:stashed_join] = stashed_left_joins return buckets, Arel::Nodes::OuterJoin else stashed_left_joins.unshift construct_join_dependency(left_joins, Arel::Nodes::OuterJoin) end end joins = joins_values.dup if joins.last.is_a?(ActiveRecord::Associations::JoinDependency) stashed_eager_load = joins.pop if joins.last.base_klass == klass end joins.each_with_index do |join, i| joins[i] = Arel::Nodes::StringJoin.new(Arel.sql(join.strip)) if join.is_a?(String) end while joins.first.is_a?(Arel::Nodes::Join) join_node = joins.shift if !join_node.is_a?(Arel::Nodes::LeadingJoin) && (stashed_eager_load || stashed_left_joins) buckets[:join_node] << join_node else buckets[:leading_join] << join_node end end buckets[:association_join] = select_association_list(joins, buckets[:stashed_join]) do |join| if join.is_a?(Arel::Nodes::Join) buckets[:join_node] << join else raise "unknown class: %s" % join.class.name end end buckets[:stashed_join].concat stashed_left_joins if stashed_left_joins buckets[:stashed_join] << stashed_eager_load if stashed_eager_load return buckets, Arel::Nodes::InnerJoin end
# File lib/active_record/relation/query_methods.rb, line 1122 def build_join_dependencies associations = joins_values | left_outer_joins_values associations |= eager_load_values unless eager_load_values.empty? associations |= includes_values unless includes_values.empty? join_dependencies = [] join_dependencies.unshift construct_join_dependency( select_association_list(associations, join_dependencies), nil ) end
# File lib/active_record/relation/query_methods.rb, line 1262 def build_joins(join_sources, aliases = nil) return join_sources if joins_values.empty? && left_outer_joins_values.empty? buckets, join_type = build_join_buckets association_joins = buckets[:association_join] stashed_joins = buckets[:stashed_join] leading_joins = buckets[:leading_join] join_nodes = buckets[:join_node] join_sources.concat(leading_joins) unless leading_joins.empty? unless association_joins.empty? && stashed_joins.empty? alias_tracker = alias_tracker(leading_joins + join_nodes, aliases) join_dependency = construct_join_dependency(association_joins, join_type) join_sources.concat(join_dependency.join_constraints(stashed_joins, alias_tracker, references_values)) end join_sources.concat(join_nodes) unless join_nodes.empty? join_sources end
# File lib/active_record/relation/query_methods.rb, line 1373 def build_order(arel) orders = order_values.compact_blank arel.order(*orders) unless orders.empty? end
# File lib/active_record/relation/query_methods.rb, line 1284 def build_select(arel) if select_values.any? arel.project(*arel_columns(select_values)) elsif klass.ignored_columns.any? arel.project(*klass.column_names.map { |field| table[field] }) else arel.project(table[Arel.star]) end end
Checks to make sure that the arguments are not blank. Note that if some blank-like object were initially passed into the query method, then this method will not raise an error.
Example:
Post.references() # raises an error Post.references([]) # does not raise an error
This particular method should be called with a method_name and the args passed into that method as an input. For example:
def references(*args)
check_if_method_has_arguments!("references", args) ...
end
# File lib/active_record/relation/query_methods.rb, line 1488 def check_if_method_has_arguments!(method_name, args, message = nil) if args.blank? raise ArgumentError, message || "The method .#{method_name}() must contain arguments." elsif block_given? yield args else args.flatten! args.compact_blank! end end
# File lib/active_record/relation/query_methods.rb, line 1432 def column_references(order_args) references = order_args.grep(String) references.map! { |arg| arg =~ /^\W?(\w+)\W?\./ && $1 }.compact! references end
# File lib/active_record/relation/query_methods.rb, line 1362 def does_not_support_reverse?(order) # Account for String subclasses like Arel::Nodes::SqlLiteral that # override methods like #count. order = String.new(order) unless order.instance_of?(String) # Uses SQL function with multiple arguments. (order.include?(",") && order.split(",").find { |section| section.count("(") != section.count(")") }) || # Uses "nulls first" like construction. /\bnulls\s+(?:first|last)\b/i.match?(order) end
# File lib/active_record/relation/query_methods.rb, line 1114 def each_join_dependencies(join_dependencies = build_join_dependencies) join_dependencies.each do |join_dependency| join_dependency.each do |join| yield join end end end
# File lib/active_record/relation/query_methods.rb, line 1107 def lookup_table_klass_from_join_dependencies(table_name) each_join_dependencies do |join| return join.base_klass if table_name == join.table_name end nil end
# File lib/active_record/relation/query_methods.rb, line 1438 def order_column(field) arel_column(field) do |attr_name| if attr_name == "count" && !group_values.empty? table[attr_name] else Arel.sql(connection.quote_table_name(attr_name)) end end end
# File lib/active_record/relation/query_methods.rb, line 1393 def preprocess_order_args(order_args) @klass.disallow_raw_sql!( order_args.flat_map { |a| a.is_a?(Hash) ? a.keys : a }, permit: connection.column_name_with_order_matcher ) validate_order_args(order_args) references = column_references(order_args) self.references_values |= references unless references.empty? # if a symbol is given we prepend the quoted table name order_args.map! do |arg| case arg when Symbol order_column(arg.to_s).asc when Hash arg.map { |field, dir| case field when Arel::Nodes::SqlLiteral field.public_send(dir.downcase) else order_column(field.to_s).public_send(dir.downcase) end } else arg end end.flatten! end
# File lib/active_record/relation/query_methods.rb, line 1448 def resolve_arel_attributes(attrs) attrs.flat_map do |attr| case attr when Arel::Predications attr when Hash attr.flat_map do |table, columns| table = table.to_s Array(columns).map do |column| predicate_builder.resolve_arel_attribute(table, column) end end else attr = attr.to_s if attr.include?(".") table, column = attr.split(".", 2) predicate_builder.resolve_arel_attribute(table, column) else attr end end end end
# File lib/active_record/relation/query_methods.rb, line 1333 def reverse_sql_order(order_query) if order_query.empty? return [table[primary_key].desc] if primary_key raise IrreversibleOrderError, "Relation has no current order and table has no primary key to be used as default order" end order_query.flat_map do |o| case o when Arel::Attribute o.desc when Arel::Nodes::Ordering o.reverse when Arel::Nodes::NodeExpression o.desc when String if does_not_support_reverse?(o) raise IrreversibleOrderError, "Order #{o.inspect} cannot be reversed automatically" end o.split(",").map! do |s| s.strip! s.gsub!(/\sasc\Z/i, " DESC") || s.gsub!(/\sdesc\Z/i, " ASC") || (s << " DESC") end else o end end end
# File lib/active_record/relation/query_methods.rb, line 1424 def sanitize_order_arguments(order_args) order_args.map! do |arg| klass.sanitize_sql_for_order(arg) end order_args.flatten! order_args.compact_blank! end
# File lib/active_record/relation/query_methods.rb, line 1194 def select_association_list(associations, stashed_joins = nil) result = [] associations.each do |association| case association when Hash, Symbol, Array result << association when ActiveRecord::Associations::JoinDependency stashed_joins&.<< association else yield association if block_given? end end result end
# File lib/active_record/relation/query_methods.rb, line 1504 def structurally_incompatible_values_for(other) values = other.values STRUCTURAL_VALUE_METHODS.reject do |method| v1, v2 = @values[method], values[method] if v1.is_a?(Array) next true unless v2.is_a?(Array) v1 = v1.uniq v2 = v2.uniq end v1 == v2 end end
# File lib/active_record/relation/query_methods.rb, line 1327 def table_name_matches?(from) table_name = Regexp.escape(table.name) quoted_table_name = Regexp.escape(connection.quote_table_name(table.name)) /(?:\A|(?<!FROM)\s)(?:\b#{table_name}\b|#{quoted_table_name})(?!\.)/i.match?(from.to_s) end
# File lib/active_record/relation/query_methods.rb, line 1381 def validate_order_args(args) args.each do |arg| next unless arg.is_a?(Hash) arg.each do |_key, value| unless VALID_DIRECTIONS.include?(value) raise ArgumentError, "Direction \"#{value}\" is invalid. Valid directions are: #{VALID_DIRECTIONS.to_a.inspect}" end end end end