Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: 5a687e930f
Fetching contributors…

Cannot retrieve contributors at this time

644 lines (560 sloc) 22.423 kb
# -*- coding: utf-8 -*-
module ActiveRecord
# = Active Record Relation
class Relation
JoinOperation = Struct.new(:relation, :join_class, :on)
MULTI_VALUE_METHODS = [:includes, :eager_load, :preload, :select, :group,
:order, :joins, :where, :having, :bind, :references,
:extending]
SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :from, :reordering,
:reverse_order, :distinct, :create_with, :uniq]
VALUE_METHODS = MULTI_VALUE_METHODS + SINGLE_VALUE_METHODS
include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches, Explain, Delegation
attr_reader :table, :klass, :loaded
attr_accessor :default_scoped
alias :model :klass
alias :loaded? :loaded
alias :default_scoped? :default_scoped
def initialize(klass, table, values = {})
@klass = klass
@table = table
@values = values
@loaded = false
@default_scoped = false
end
def initialize_copy(other)
# This method is a hot spot, so for now, use Hash[] to dup the hash.
# https://bugs.ruby-lang.org/issues/7166
@values = Hash[@values]
@values[:bind] = @values[:bind].dup if @values.key? :bind
reset
end
def insert(values) # :nodoc:
primary_key_value = nil
if primary_key && Hash === values
primary_key_value = values[values.keys.find { |k|
k.name == primary_key
}]
if !primary_key_value && connection.prefetch_primary_key?(klass.table_name)
primary_key_value = connection.next_sequence_value(klass.sequence_name)
values[klass.arel_table[klass.primary_key]] = primary_key_value
end
end
im = arel.create_insert
im.into @table
substitutes, binds = substitute_values values
if values.empty? # empty insert
im.values = Arel.sql(connection.empty_insert_statement_value)
else
im.insert substitutes
end
@klass.connection.insert(
im,
'SQL',
primary_key,
primary_key_value,
nil,
binds)
end
def update_record(values, id, id_was) # :nodoc:
substitutes, binds = substitute_values values
um = @klass.unscoped.where(@klass.arel_table[@klass.primary_key].eq(id_was || id)).arel.compile_update(substitutes)
@klass.connection.update(
um,
'SQL',
binds)
end
def substitute_values(values) # :nodoc:
substitutes = values.sort_by { |arel_attr,_| arel_attr.name }
binds = substitutes.map do |arel_attr, value|
[@klass.columns_hash[arel_attr.name], value]
end
substitutes.each_with_index do |tuple, i|
tuple[1] = @klass.connection.substitute_at(binds[i][0], i)
end
[substitutes, binds]
end
# Initializes new record from relation while maintaining the current
# scope.
#
# Expects arguments in the same format as +Base.new+.
#
# users = User.where(name: 'DHH')
# user = users.new # => #<User id: nil, name: "DHH", created_at: nil, updated_at: nil>
#
# You can also pass a block to new with the new record as argument:
#
# user = users.new { |user| user.name = 'Oscar' }
# user.name # => Oscar
def new(*args, &block)
scoping { @klass.new(*args, &block) }
end
alias build new
# Tries to create a new record with the same scoped attributes
# defined in the relation. Returns the initialized object if validation fails.
#
# Expects arguments in the same format as +Base.create+.
#
# ==== Examples
# users = User.where(name: 'Oscar')
# users.create # #<User id: 3, name: "oscar", ...>
#
# users.create(name: 'fxn')
# users.create # #<User id: 4, name: "fxn", ...>
#
# users.create { |user| user.name = 'tenderlove' }
# # #<User id: 5, name: "tenderlove", ...>
#
# users.create(name: nil) # validation on name
# # #<User id: nil, name: nil, ...>
def create(*args, &block)
scoping { @klass.create(*args, &block) }
end
# Similar to #create, but calls +create!+ on the base class. Raises
# an exception if a validation error occurs.
#
# Expects arguments in the same format as <tt>Base.create!</tt>.
def create!(*args, &block)
scoping { @klass.create!(*args, &block) }
end
def first_or_create(attributes = nil, &block) # :nodoc:
first || create(attributes, &block)
end
def first_or_create!(attributes = nil, &block) # :nodoc:
first || create!(attributes, &block)
end
def first_or_initialize(attributes = nil, &block) # :nodoc:
first || new(attributes, &block)
end
# Finds the first record with the given attributes, or creates a record with the attributes
# if one is not found.
#
# ==== Examples
# # Find the first user named Penélope or create a new one.
# User.find_or_create_by(first_name: 'Penélope')
# # => <User id: 1, first_name: 'Penélope', last_name: nil>
#
# # Find the first user named Penélope or create a new one.
# # We already have one so the existing record will be returned.
# User.find_or_create_by(first_name: 'Penélope')
# # => <User id: 1, first_name: 'Penélope', last_name: nil>
#
# # Find the first user named Scarlett or create a new one with a particular last name.
# User.create_with(last_name: 'Johansson').find_or_create_by(first_name: 'Scarlett')
# # => <User id: 2, first_name: 'Scarlett', last_name: 'Johansson'>
#
# # Find the first user named Scarlett or create a new one with a different last name.
# # We already have one so the existing record will be returned.
# User.find_or_create_by(first_name: 'Scarlett') do |user|
# user.last_name = "O'Hara"
# end
# # => <User id: 2, first_name: 'Scarlett', last_name: 'Johansson'>
def find_or_create_by(attributes, &block)
find_by(attributes) || create(attributes, &block)
end
# Like <tt>find_or_create_by</tt>, but calls <tt>create!</tt> so an exception is raised if the created record is invalid.
def find_or_create_by!(attributes, &block)
find_by(attributes) || create!(attributes, &block)
end
# Like <tt>find_or_create_by</tt>, but calls <tt>new</tt> instead of <tt>create</tt>.
def find_or_initialize_by(attributes, &block)
find_by(attributes) || new(attributes, &block)
end
# Runs EXPLAIN on the query or queries triggered by this relation and
# returns the result as a string. The string is formatted imitating the
# ones printed by the database shell.
#
# Note that this method actually runs the queries, since the results of some
# are needed by the next ones when eager loading is going on.
#
# Please see further details in the
# {Active Record Query Interface guide}[http://guides.rubyonrails.org/active_record_querying.html#running-explain].
def explain
exec_explain(collecting_queries_for_explain { exec_queries })
end
# Converts relation objects to Array.
def to_a
load
@records
end
def as_json(options = nil) #:nodoc:
to_a.as_json(options)
end
# Returns size of the records.
def size
loaded? ? @records.length : count
end
# Returns true if there are no records.
def empty?
return @records.empty? if loaded?
c = count
c.respond_to?(:zero?) ? c.zero? : c.empty?
end
# Returns true if there are any records.
def any?
if block_given?
to_a.any? { |*block_args| yield(*block_args) }
else
!empty?
end
end
# Returns true if there is more than one record.
def many?
if block_given?
to_a.many? { |*block_args| yield(*block_args) }
else
limit_value ? to_a.many? : size > 1
end
end
# Scope all queries to the current scope.
#
# Comment.where(post_id: 1).scoping do
# Comment.first
# end
# # => SELECT "comments".* FROM "comments" WHERE "comments"."post_id" = 1 ORDER BY "comments"."id" ASC LIMIT 1
#
# Please check unscoped if you want to remove all previous scopes (including
# the default_scope) during the execution of a block.
def scoping
previous, klass.current_scope = klass.current_scope, self
yield
ensure
klass.current_scope = previous
end
# Updates all records with details given if they match a set of conditions supplied, limits and order can
# also be supplied. This method constructs a single SQL UPDATE statement and sends it straight to the
# database. It does not instantiate the involved models and it does not trigger Active Record callbacks
# or validations.
#
# ==== Parameters
#
# * +updates+ - A string, array, or hash representing the SET part of an SQL statement.
#
# ==== Examples
#
# # Update all customers with the given attributes
# Customer.update_all wants_email: true
#
# # Update all books with 'Rails' in their title
# Book.where('title LIKE ?', '%Rails%').update_all(author: 'David')
#
# # Update all books that match conditions, but limit it to 5 ordered by date
# Book.where('title LIKE ?', '%Rails%').order(:created_at).limit(5).update_all(author: 'David')
def update_all(updates)
raise ArgumentError, "Empty list of attributes to change" if updates.blank?
stmt = Arel::UpdateManager.new(arel.engine)
stmt.set Arel.sql(@klass.send(:sanitize_sql_for_assignment, updates))
stmt.table(table)
stmt.key = table[primary_key]
if with_default_scope.joins_values.any?
@klass.connection.join_to_update(stmt, arel)
else
stmt.take(arel.limit)
stmt.order(*arel.orders)
stmt.wheres = arel.constraints
end
@klass.connection.update stmt, 'SQL', bind_values
end
# Updates an object (or multiple objects) and saves it to the database, if validations pass.
# The resulting object is returned whether the object was saved successfully to the database or not.
#
# ==== Parameters
#
# * +id+ - This should be the id or an array of ids to be updated.
# * +attributes+ - This should be a hash of attributes or an array of hashes.
#
# ==== Examples
#
# # Updates one record
# Person.update(15, user_name: 'Samuel', group: 'expert')
#
# # Updates multiple records
# people = { 1 => { "first_name" => "David" }, 2 => { "first_name" => "Jeremy" } }
# Person.update(people.keys, people.values)
def update(id, attributes)
if id.is_a?(Array)
id.map.with_index { |one_id, idx| update(one_id, attributes[idx]) }
else
object = find(id)
object.update(attributes)
object
end
end
# Destroys the records matching +conditions+ by instantiating each
# record and calling its +destroy+ method. Each object's callbacks are
# executed (including <tt>:dependent</tt> association options). Returns the
# collection of objects that were destroyed; each will be frozen, to
# reflect that no changes should be made (since they can't be persisted).
#
# Note: Instantiation, callback execution, and deletion of each
# record can be time consuming when you're removing many records at
# once. It generates at least one SQL +DELETE+ query per record (or
# possibly more, to enforce your callbacks). If you want to delete many
# rows quickly, without concern for their associations or callbacks, use
# +delete_all+ instead.
#
# ==== Parameters
#
# * +conditions+ - A string, array, or hash that specifies which records
# to destroy. If omitted, all records are destroyed. See the
# Conditions section in the introduction to ActiveRecord::Base for
# more information.
#
# ==== Examples
#
# Person.destroy_all("last_login < '2004-04-04'")
# Person.destroy_all(status: "inactive")
# Person.where(age: 0..18).destroy_all
def destroy_all(conditions = nil)
if conditions
where(conditions).destroy_all
else
to_a.each {|object| object.destroy }.tap { reset }
end
end
# Destroy an object (or multiple objects) that has the given id. The object is instantiated first,
# therefore all callbacks and filters are fired off before the object is deleted. This method is
# less efficient than ActiveRecord#delete but allows cleanup methods and other actions to be run.
#
# This essentially finds the object (or multiple objects) with the given id, creates a new object
# from the attributes, and then calls destroy on it.
#
# ==== Parameters
#
# * +id+ - Can be either an Integer or an Array of Integers.
#
# ==== Examples
#
# # Destroy a single object
# Todo.destroy(1)
#
# # Destroy multiple objects
# todos = [1,2,3]
# Todo.destroy(todos)
def destroy(id)
if id.is_a?(Array)
id.map { |one_id| destroy(one_id) }
else
find(id).destroy
end
end
# Deletes the records matching +conditions+ without instantiating the records
# first, and hence not calling the +destroy+ method nor invoking callbacks. This
# is a single SQL DELETE statement that goes straight to the database, much more
# efficient than +destroy_all+. Be careful with relations though, in particular
# <tt>:dependent</tt> rules defined on associations are not honored. Returns the
# number of rows affected.
#
# Post.delete_all("person_id = 5 AND (category = 'Something' OR category = 'Else')")
# Post.delete_all(["person_id = ? AND (category = ? OR category = ?)", 5, 'Something', 'Else'])
# Post.where(person_id: 5).where(category: ['Something', 'Else']).delete_all
#
# Both calls delete the affected posts all at once with a single DELETE statement.
# If you need to destroy dependent associations or call your <tt>before_*</tt> or
# +after_destroy+ callbacks, use the +destroy_all+ method instead.
#
# If a limit scope is supplied, +delete_all+ raises an ActiveRecord error:
#
# Post.limit(100).delete_all
# # => ActiveRecord::ActiveRecordError: delete_all doesn't support limit scope
def delete_all(conditions = nil)
raise ActiveRecordError.new("delete_all doesn't support limit scope") if self.limit_value
if conditions
where(conditions).delete_all
else
stmt = Arel::DeleteManager.new(arel.engine)
stmt.from(table)
if with_default_scope.joins_values.any?
@klass.connection.join_to_delete(stmt, arel, table[primary_key])
else
stmt.wheres = arel.constraints
end
affected = @klass.connection.delete(stmt, 'SQL', bind_values)
reset
affected
end
end
# Deletes the row with a primary key matching the +id+ argument, using a
# SQL +DELETE+ statement, and returns the number of rows deleted. Active
# Record objects are not instantiated, so the object's callbacks are not
# executed, including any <tt>:dependent</tt> association options.
#
# You can delete multiple rows at once by passing an Array of <tt>id</tt>s.
#
# Note: Although it is often much faster than the alternative,
# <tt>#destroy</tt>, skipping callbacks might bypass business logic in
# your application that ensures referential integrity or performs other
# essential jobs.
#
# ==== Examples
#
# # Delete a single row
# Todo.delete(1)
#
# # Delete multiple rows
# Todo.delete([2,3,4])
def delete(id_or_array)
where(primary_key => id_or_array).delete_all
end
# Causes the records to be loaded from the database if they have not
# been loaded already. You can use this if for some reason you need
# to explicitly load some records before actually using them. The
# return value is the relation itself, not the records.
#
# Post.where(published: true).load # => #<ActiveRecord::Relation>
def load
exec_queries unless loaded?
self
end
# Forces reloading of relation.
def reload
reset
load
end
def reset
@first = @last = @to_sql = @order_clause = @scope_for_create = @arel = @loaded = nil
@should_eager_load = @join_dependency = nil
@records = []
self
end
# Returns sql statement for the relation.
#
# User.where(name: 'Oscar').to_sql
# # => SELECT "users".* FROM "users" WHERE "users"."name" = 'Oscar'
def to_sql
@to_sql ||= klass.connection.to_sql(arel, bind_values.dup)
end
# Returns a hash of where conditions.
#
# User.where(name: 'Oscar').where_values_hash
# # => {name: "Oscar"}
def where_values_hash
scope = with_default_scope
equalities = scope.where_values.grep(Arel::Nodes::Equality).find_all { |node|
node.left.relation.name == table_name
}
binds = Hash[scope.bind_values.find_all(&:first).map { |column, v| [column.name, v] }]
binds.merge!(Hash[bind_values.find_all(&:first).map { |column, v| [column.name, v] }])
Hash[equalities.map { |where|
name = where.left.name
[name, binds.fetch(name.to_s) { where.right }]
}]
end
def scope_for_create
@scope_for_create ||= where_values_hash.merge(create_with_value)
end
# Returns true if relation needs eager loading.
def eager_loading?
@should_eager_load ||=
eager_load_values.any? ||
includes_values.any? && (joined_includes_values.any? || references_eager_loaded_tables?)
end
# Joins that are also marked for preloading. In which case we should just eager load them.
# Note that this is a naive implementation because we could have strings and symbols which
# represent the same association, but that aren't matched by this. Also, we could have
# nested hashes which partially match, e.g. { a: :b } & { a: [:b, :c] }
def joined_includes_values
includes_values & joins_values
end
# +uniq+ and +uniq!+ are silently deprecated. +uniq_value+ delegates to +distinct_value+
# to maintain backwards compatibility. Use +distinct_value+ instead.
def uniq_value
distinct_value
end
# Compares two relations for equality.
def ==(other)
case other
when Relation
other.to_sql == to_sql
when Array
to_a == other
end
end
def pretty_print(q)
q.pp(self.to_a)
end
def with_default_scope #:nodoc:
if default_scoped? && default_scope = klass.send(:build_default_scope)
default_scope = default_scope.merge(self)
default_scope.default_scoped = false
default_scope
else
self
end
end
# Returns true if relation is blank.
def blank?
to_a.blank?
end
def values
Hash[@values]
end
def inspect
entries = to_a.take([limit_value, 11].compact.min).map!(&:inspect)
entries[10] = '...' if entries.size == 11
"#<#{self.class.name} [#{entries.join(', ')}]>"
end
private
def exec_queries
default_scoped = with_default_scope
if default_scoped.equal?(self)
@records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel, bind_values)
preload = preload_values
preload += includes_values unless eager_loading?
preload.each do |associations|
ActiveRecord::Associations::Preloader.new(@records, associations).run
end
@records.each { |record| record.readonly! } if readonly_value
else
@records = default_scoped.to_a
end
@loaded = true
@records
end
def references_eager_loaded_tables?
joined_tables = arel.join_sources.map do |join|
if join.is_a?(Arel::Nodes::StringJoin)
tables_in_string(join.left)
else
[join.left.table_name, join.left.table_alias]
end
end
joined_tables += [table.name, table.table_alias]
# always convert table names to downcase as in Oracle quoted table names are in uppercase
joined_tables = joined_tables.flatten.compact.map { |t| t.downcase }.uniq
string_tables = tables_in_string(to_sql)
if (references_values - joined_tables).any?
true
elsif !ActiveRecord::Base.disable_implicit_join_references &&
(string_tables - joined_tables).any?
ActiveSupport::Deprecation.warn(
"It looks like you are eager loading table(s) (one of: #{string_tables.join(', ')}) " \
"that are referenced in a string SQL snippet. For example: \n" \
"\n" \
" Post.includes(:comments).where(\"comments.title = 'foo'\")\n" \
"\n" \
"Currently, Active Record recognizes the table in the string, and knows to JOIN the " \
"comments table to the query, rather than loading comments in a separate query. " \
"However, doing this without writing a full-blown SQL parser is inherently flawed. " \
"Since we don't want to write an SQL parser, we are removing this functionality. " \
"From now on, you must explicitly tell Active Record when you are referencing a table " \
"from a string:\n" \
"\n" \
" Post.includes(:comments).where(\"comments.title = 'foo'\").references(:comments)\n" \
"\n" \
"If you don't rely on implicit join references you can disable the feature entirely " \
"by setting `config.active_record.disable_implicit_join_references = true`."
)
true
else
false
end
end
def tables_in_string(string)
return [] if string.blank?
# always convert table names to downcase as in Oracle quoted table names are in uppercase
# ignore raw_sql_ that is used by Oracle adapter as alias for limit/offset subqueries
string.scan(/([a-zA-Z_][.\w]+).?\./).flatten.map{ |s| s.downcase }.uniq - ['raw_sql_']
end
end
end
Jump to Line
Something went wrong with that request. Please try again.