require 'active_support/core_ext/object/blank'
module ActiveRecord
# = Active Record Relation
class Relation
JoinOperation = Struct.new(:relation, :join_class, :on)
ASSOCIATION_METHODS = [:includes, :eager_load, :preload]
MULTI_VALUE_METHODS = [:select, :group, :order, :joins, :where, :having, :bind]
SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :create_with, :from]
include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches
# These are explicitly delegated to improve performance (avoids method_missing)
delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to => :to_a
delegate :table_name, :primary_key, :to => :klass
attr_reader :table, :klass, :loaded
attr_accessor :extensions
alias :loaded? :loaded
def initialize(klass, table)
@klass, @table = klass, table
@implicit_readonly = nil
@loaded = false
SINGLE_VALUE_METHODS.each {|v| instance_variable_set(:"@#{v}_value", nil)}
(ASSOCIATION_METHODS + MULTI_VALUE_METHODS).each {|v| instance_variable_set(:"@#{v}_values", [])}
@extensions = []
end
def insert(values)
im = arel.compile_insert values
im.into @table
primary_key_value = nil
if primary_key && Hash === values
primary_key_value = values[values.keys.find { |k|
k.name == primary_key
}]
end
@klass.connection.insert(
im.to_sql,
'SQL',
primary_key,
primary_key_value)
end
def new(*args, &block)
scoping { @klass.new(*args, &block) }
end
def initialize_copy(other)
reset
end
alias build new
def create(*args, &block)
scoping { @klass.create(*args, &block) }
end
def create!(*args, &block)
scoping { @klass.create!(*args, &block) }
end
def respond_to?(method, include_private = false)
return true if arel.respond_to?(method, include_private) || Array.method_defined?(method) || @klass.respond_to?(method, include_private)
if match = DynamicFinderMatch.match(method)
return true if @klass.send(:all_attributes_exists?, match.attribute_names)
elsif match = DynamicScopeMatch.match(method)
return true if @klass.send(:all_attributes_exists?, match.attribute_names)
else
super
end
end
def to_a
return @records if loaded?
@records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql, @bind_values)
preload = @preload_values
preload += @includes_values unless eager_loading?
preload.each {|associations| @klass.send(:preload_associations, @records, associations) }
# @readonly_value is true only if set explicitly. @implicit_readonly is true if there
# are JOINS and no explicit SELECT.
readonly = @readonly_value.nil? ? @implicit_readonly : @readonly_value
@records.each { |record| record.readonly! } if readonly
@loaded = true
@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?
loaded? ? @records.empty? : count.zero?
end
def any?
if block_given?
to_a.any? { |*block_args| yield(*block_args) }
else
!empty?
end
end
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.
#
# ==== Example
#
# Comment.where(:post_id => 1).scoping do
# Comment.first # SELECT * FROM comments WHERE post_id = 1
# end
#
# Please check unscoped if you want to remove all previous scopes (including
# the default_scope) during the execution of a block.
def scoping
@klass.scoped_methods << self
begin
yield
ensure
@klass.scoped_methods.pop
end
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.
# * +conditions+ - A string, array, or hash representing the WHERE part of an SQL statement.
# See conditions in the intro.
# * +options+ - Additional options are <tt>:limit</tt> and <tt>:order</tt>, see the examples for usage.
#
# ==== Examples
#
# # Update all customers with the given attributes
# Customer.update_all :wants_email => true
#
# # Update all books with 'Rails' in their title
# Book.update_all "author = 'David'", "title LIKE '%Rails%'"
#
# # Update all avatars migrated more than a week ago
# Avatar.update_all ['migrated_at = ?', Time.now.utc], ['migrated_at > ?', 1.week.ago]
#
# # Update all books that match conditions, but limit it to 5 ordered by date
# Book.update_all "author = 'David'", "title LIKE '%Rails%'", :order => 'created_at', :limit => 5
def update_all(updates, conditions = nil, options = {})
if conditions || options.present?
where(conditions).apply_finder_options(options.slice(:limit, :order)).update_all(updates)
else
limit = nil
order = []
# Apply limit and order only if they're both present
if @limit_value.present? == @order_values.present?
limit = arel.limit
order = arel.orders
end
stmt = arel.compile_update(Arel.sql(@klass.send(:sanitize_sql_for_assignment, updates)))
stmt.take limit
stmt.order(*order)
stmt.key = table[primary_key]
@klass.connection.update stmt.to_sql
end
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)
idx = -1
id.collect { |one_id| idx += 1; update(one_id, attributes[idx]) }
else
object = find(id)
object.update_attributes(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 and
# +before_destroy+/+after_destroy+ Observer methods). 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")
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.
#
# ==== Parameters
#
# * +conditions+ - Conditions are specified the same way as with +find+ method.
#
# ==== Example
#
# Post.delete_all("person_id = 5 AND (category = 'Something' OR category = 'Else')")
# Post.delete_all(["person_id = ? AND (category = ? OR category = ?)", 5, 'Something', 'Else'])
#
# 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.
def delete_all(conditions = nil)
if conditions
where(conditions).delete_all
else
statement = arel.compile_delete
affected = @klass.connection.delete statement.to_sql
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 or
# Observer methods.
#
# 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
def reload
reset
to_a # force reload
self
end
def reset
@first = @last = @to_sql = @order_clause = @scope_for_create = @arel = @loaded = nil
@should_eager_load = @join_dependency = nil
@records = []
self
end
def to_sql
@to_sql ||= arel.to_sql
end
def where_values_hash
equalities = @where_values.grep(Arel::Nodes::Equality).find_all { |node|
node.left.relation.name == table_name
}
Hash[equalities.map { |where| [where.left.name, where.right] }]
end
def scope_for_create
@scope_for_create ||= where_values_hash.merge(@create_with_value || {})
end
def eager_loading?
@should_eager_load ||= (@eager_load_values.any? || (@includes_values.any? && references_eager_loaded_tables?))
end
def ==(other)
case other
when Relation
other.to_sql == to_sql
when Array
to_a == other
end
end
def inspect
to_a.inspect
end
protected
def method_missing(method, *args, &block)
if Array.method_defined?(method)
to_a.send(method, *args, &block)
elsif @klass.scopes[method]
merge(@klass.send(method, *args, &block))
elsif @klass.respond_to?(method)
scoping { @klass.send(method, *args, &block) }
elsif arel.respond_to?(method)
arel.send(method, *args, &block)
else
super
end
end
private
def references_eager_loaded_tables?
# always convert table names to downcase as in Oracle quoted table names are in uppercase
joined_tables = (tables_in_string(arel.join_sql) + [table.name, table.table_alias]).compact.map{ |t| t.downcase }.uniq
(tables_in_string(to_sql) - joined_tables).any?
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