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rails--rails/activerecord/lib/active_record/relation.rb

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module ActiveRecord
class Relation
JoinOperation = Struct.new(:relation, :join_class, :on)
ASSOCIATION_METHODS = [:includes, :eager_load, :preload]
MULTI_VALUE_METHODS = [:select, :group, :order, :joins, :where, :having]
SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :create_with, :from]
include FinderMethods, Calculations, SpawnMethods, QueryMethods
delegate :length, :collect, :map, :each, :all?, :include?, :to => :to_a
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delegate :insert, :update, :to => :arel
attr_reader :table, :klass
def initialize(klass, table)
@klass, @table = klass, table
(ASSOCIATION_METHODS + MULTI_VALUE_METHODS).each {|v| instance_variable_set(:"@#{v}_values", [])}
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end
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def new(*args, &block)
with_create_scope { @klass.new(*args, &block) }
end
alias build new
def create(*args, &block)
with_create_scope { @klass.create(*args, &block) }
end
def create!(*args, &block)
with_create_scope { @klass.create!(*args, &block) }
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end
def respond_to?(method, include_private = false)
return true if arel.respond_to?(method, include_private) || Array.method_defined?(method)
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
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def to_a
return @records if loaded?
@records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql)
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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 explicity. @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
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@loaded = true
@records
end
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def size
loaded? ? @records.length : count
end
def empty?
loaded? ? @records.empty? : count.zero?
end
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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
arel.send(:taken).present? ? to_a.many? : size > 1
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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}
reset
end
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end
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def delete_all
arel.delete.tap { reset }
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end
def delete(id_or_array)
where(@klass.primary_key => id_or_array).delete_all
end
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def loaded?
@loaded
end
def reload
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reset
to_a # force reload
self
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end
def reset
@first = @last = @to_sql = @order_clause = @scope_for_create = @arel = @loaded = nil
@should_eager_load = @join_dependency = nil
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@records = []
self
end
def primary_key
@primary_key ||= table[@klass.primary_key]
end
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def to_sql
@to_sql ||= arel.to_sql
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end
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def scope_for_create
@scope_for_create ||= begin
@create_with_value || wheres.inject({}) do |hash, where|
hash[where.operand1.name] = where.operand2.value if where.is_a?(Arel::Predicates::Equality)
hash
end
end
end
def eager_loading?
@should_eager_load ||= (@eager_load_values.any? || (@includes_values.any? && references_eager_loaded_tables?))
end
protected
def method_missing(method, *args, &block)
if Array.method_defined?(method)
to_a.send(method, *args, &block)
elsif arel.respond_to?(method)
arel.send(method, *args, &block)
elsif match = DynamicFinderMatch.match(method)
attributes = match.attribute_names
super unless @klass.send(:all_attributes_exists?, attributes)
if match.finder?
find_by_attributes(match, attributes, *args)
elsif match.instantiator?
find_or_instantiator_by_attributes(match, attributes, *args, &block)
end
else
super
end
end
private
def with_create_scope
@klass.send(:with_scope, :create => scope_for_create, :find => {}) { yield }
end
def references_eager_loaded_tables?
joined_tables = (tables_in_string(arel.joins(arel)) + [table.name, table.table_alias]).compact.uniq
(tables_in_string(to_sql) - joined_tables).any?
end
def tables_in_string(string)
return [] if string.blank?
string.scan(/([a-zA-Z_][\.\w]+).?\./).flatten.uniq
end
end
end