require 'yaml'
require 'set'
require 'active_support/dependencies'
require 'active_support/time'
require 'active_support/core_ext/class/attribute_accessors'
require 'active_support/core_ext/class/delegating_attributes'
require 'active_support/core_ext/class/inheritable_attributes'
require 'active_support/core_ext/array/extract_options'
require 'active_support/core_ext/hash/deep_merge'
require 'active_support/core_ext/hash/indifferent_access'
require 'active_support/core_ext/hash/slice'
require 'active_support/core_ext/string/behavior'
require 'active_support/core_ext/symbol'
require 'active_support/core_ext/object/metaclass'
module ActiveRecord #:nodoc:
# Generic Active Record exception class.
class ActiveRecordError < StandardError
end
# Raised when the single-table inheritance mechanism fails to locate the subclass
# (for example due to improper usage of column that +inheritance_column+ points to).
class SubclassNotFound < ActiveRecordError #:nodoc:
end
# Raised when an object assigned to an association has an incorrect type.
#
# class Ticket < ActiveRecord::Base
# has_many :patches
# end
#
# class Patch < ActiveRecord::Base
# belongs_to :ticket
# end
#
# # Comments are not patches, this assignment raises AssociationTypeMismatch.
# @ticket.patches << Comment.new(:content => "Please attach tests to your patch.")
class AssociationTypeMismatch < ActiveRecordError
end
# Raised when unserialized object's type mismatches one specified for serializable field.
class SerializationTypeMismatch < ActiveRecordError
end
# Raised when adapter not specified on connection (or configuration file <tt>config/database.yml</tt> misses adapter field).
class AdapterNotSpecified < ActiveRecordError
end
# Raised when Active Record cannot find database adapter specified in <tt>config/database.yml</tt> or programmatically.
class AdapterNotFound < ActiveRecordError
end
# Raised when connection to the database could not been established (for example when <tt>connection=</tt> is given a nil object).
class ConnectionNotEstablished < ActiveRecordError
end
# Raised when Active Record cannot find record by given id or set of ids.
class RecordNotFound < ActiveRecordError
end
# Raised by ActiveRecord::Base.save! and ActiveRecord::Base.create! methods when record cannot be
# saved because record is invalid.
class RecordNotSaved < ActiveRecordError
end
# Raised when SQL statement cannot be executed by the database (for example, it's often the case for MySQL when Ruby driver used is too old).
class StatementInvalid < ActiveRecordError
end
# Parent class for all specific exceptions which wrap database driver exceptions
# provides access to the original exception also.
class WrappedDatabaseException < StatementInvalid
attr_reader :original_exception
def initialize(message, original_exception)
super(message)
@original_exception, = original_exception
end
end
# Raised when a record cannot be inserted because it would violate a uniqueness constraint.
class RecordNotUnique < WrappedDatabaseException
end
# Raised when a record cannot be inserted or updated because it references a non-existent record.
class InvalidForeignKey < WrappedDatabaseException
end
# Raised when number of bind variables in statement given to <tt>:condition</tt> key (for example, when using +find+ method)
# does not match number of expected variables.
#
# For example, in
#
# Location.find :all, :conditions => ["lat = ? AND lng = ?", 53.7362]
#
# two placeholders are given but only one variable to fill them.
class PreparedStatementInvalid < ActiveRecordError
end
# Raised on attempt to save stale record. Record is stale when it's being saved in another query after
# instantiation, for example, when two users edit the same wiki page and one starts editing and saves
# the page before the other.
#
# Read more about optimistic locking in ActiveRecord::Locking module RDoc.
class StaleObjectError < ActiveRecordError
end
# Raised when association is being configured improperly or
# user tries to use offset and limit together with has_many or has_and_belongs_to_many associations.
class ConfigurationError < ActiveRecordError
end
# Raised on attempt to update record that is instantiated as read only.
class ReadOnlyRecord < ActiveRecordError
end
# ActiveRecord::Transactions::ClassMethods.transaction uses this exception
# to distinguish a deliberate rollback from other exceptional situations.
# Normally, raising an exception will cause the +transaction+ method to rollback
# the database transaction *and* pass on the exception. But if you raise an
# ActiveRecord::Rollback exception, then the database transaction will be rolled back,
# without passing on the exception.
#
# For example, you could do this in your controller to rollback a transaction:
#
# class BooksController < ActionController::Base
# def create
# Book.transaction do
# book = Book.new(params[:book])
# book.save!
# if today_is_friday?
# # The system must fail on Friday so that our support department
# # won't be out of job. We silently rollback this transaction
# # without telling the user.
# raise ActiveRecord::Rollback, "Call tech support!"
# end
# end
# # ActiveRecord::Rollback is the only exception that won't be passed on
# # by ActiveRecord::Base.transaction, so this line will still be reached
# # even on Friday.
# redirect_to root_url
# end
# end
class Rollback < ActiveRecordError
end
# Raised when attribute has a name reserved by Active Record (when attribute has name of one of Active Record instance methods).
class DangerousAttributeError < ActiveRecordError
end
# Raised when you've tried to access a column which wasn't loaded by your finder.
# Typically this is because <tt>:select</tt> has been specified.
class MissingAttributeError < NoMethodError
end
# Raised when unknown attributes are supplied via mass assignment.
class UnknownAttributeError < NoMethodError
end
# Raised when an error occurred while doing a mass assignment to an attribute through the
# <tt>attributes=</tt> method. The exception has an +attribute+ property that is the name of the
# offending attribute.
class AttributeAssignmentError < ActiveRecordError
attr_reader :exception, :attribute
def initialize(message, exception, attribute)
@exception = exception
@attribute = attribute
@message = message
end
end
# Raised when there are multiple errors while doing a mass assignment through the +attributes+
# method. The exception has an +errors+ property that contains an array of AttributeAssignmentError
# objects, each corresponding to the error while assigning to an attribute.
class MultiparameterAssignmentErrors < ActiveRecordError
attr_reader :errors
def initialize(errors)
@errors = errors
end
end
# Active Record objects don't specify their attributes directly, but rather infer them from the table definition with
# which they're linked. Adding, removing, and changing attributes and their type is done directly in the database. Any change
# is instantly reflected in the Active Record objects. The mapping that binds a given Active Record class to a certain
# database table will happen automatically in most common cases, but can be overwritten for the uncommon ones.
#
# See the mapping rules in table_name and the full example in link:files/README.html for more insight.
#
# == Creation
#
# Active Records accept constructor parameters either in a hash or as a block. The hash method is especially useful when
# you're receiving the data from somewhere else, like an HTTP request. It works like this:
#
# user = User.new(:name => "David", :occupation => "Code Artist")
# user.name # => "David"
#
# You can also use block initialization:
#
# user = User.new do |u|
# u.name = "David"
# u.occupation = "Code Artist"
# end
#
# And of course you can just create a bare object and specify the attributes after the fact:
#
# user = User.new
# user.name = "David"
# user.occupation = "Code Artist"
#
# == Conditions
#
# Conditions can either be specified as a string, array, or hash representing the WHERE-part of an SQL statement.
# The array form is to be used when the condition input is tainted and requires sanitization. The string form can
# be used for statements that don't involve tainted data. The hash form works much like the array form, except
# only equality and range is possible. Examples:
#
# class User < ActiveRecord::Base
# def self.authenticate_unsafely(user_name, password)
# find(:first, :conditions => "user_name = '#{user_name}' AND password = '#{password}'")
# end
#
# def self.authenticate_safely(user_name, password)
# find(:first, :conditions => [ "user_name = ? AND password = ?", user_name, password ])
# end
#
# def self.authenticate_safely_simply(user_name, password)
# find(:first, :conditions => { :user_name => user_name, :password => password })
# end
# end
#
# The <tt>authenticate_unsafely</tt> method inserts the parameters directly into the query and is thus susceptible to SQL-injection
# attacks if the <tt>user_name</tt> and +password+ parameters come directly from an HTTP request. The <tt>authenticate_safely</tt> and
# <tt>authenticate_safely_simply</tt> both will sanitize the <tt>user_name</tt> and +password+ before inserting them in the query,
# which will ensure that an attacker can't escape the query and fake the login (or worse).
#
# When using multiple parameters in the conditions, it can easily become hard to read exactly what the fourth or fifth
# question mark is supposed to represent. In those cases, you can resort to named bind variables instead. That's done by replacing
# the question marks with symbols and supplying a hash with values for the matching symbol keys:
#
# Company.find(:first, :conditions => [
# "id = :id AND name = :name AND division = :division AND created_at > :accounting_date",
# { :id => 3, :name => "37signals", :division => "First", :accounting_date => '2005-01-01' }
# ])
#
# Similarly, a simple hash without a statement will generate conditions based on equality with the SQL AND
# operator. For instance:
#
# Student.find(:all, :conditions => { :first_name => "Harvey", :status => 1 })
# Student.find(:all, :conditions => params[:student])
#
# A range may be used in the hash to use the SQL BETWEEN operator:
#
# Student.find(:all, :conditions => { :grade => 9..12 })
#
# An array may be used in the hash to use the SQL IN operator:
#
# Student.find(:all, :conditions => { :grade => [9,11,12] })
#
# == Overwriting default accessors
#
# All column values are automatically available through basic accessors on the Active Record object, but sometimes you
# want to specialize this behavior. This can be done by overwriting the default accessors (using the same
# name as the attribute) and calling <tt>read_attribute(attr_name)</tt> and <tt>write_attribute(attr_name, value)</tt> to actually change things.
# Example:
#
# class Song < ActiveRecord::Base
# # Uses an integer of seconds to hold the length of the song
#
# def length=(minutes)
# write_attribute(:length, minutes.to_i * 60)
# end
#
# def length
# read_attribute(:length) / 60
# end
# end
#
# You can alternatively use <tt>self[:attribute]=(value)</tt> and <tt>self[:attribute]</tt> instead of <tt>write_attribute(:attribute, value)</tt> and
# <tt>read_attribute(:attribute)</tt> as a shorter form.
#
# == Attribute query methods
#
# In addition to the basic accessors, query methods are also automatically available on the Active Record object.
# Query methods allow you to test whether an attribute value is present.
#
# For example, an Active Record User with the <tt>name</tt> attribute has a <tt>name?</tt> method that you can call
# to determine whether the user has a name:
#
# user = User.new(:name => "David")
# user.name? # => true
#
# anonymous = User.new(:name => "")
# anonymous.name? # => false
#
# == Accessing attributes before they have been typecasted
#
# Sometimes you want to be able to read the raw attribute data without having the column-determined typecast run its course first.
# That can be done by using the <tt><attribute>_before_type_cast</tt> accessors that all attributes have. For example, if your Account model
# has a <tt>balance</tt> attribute, you can call <tt>account.balance_before_type_cast</tt> or <tt>account.id_before_type_cast</tt>.
#
# This is especially useful in validation situations where the user might supply a string for an integer field and you want to display
# the original string back in an error message. Accessing the attribute normally would typecast the string to 0, which isn't what you
# want.
#
# == Dynamic attribute-based finders
#
# Dynamic attribute-based finders are a cleaner way of getting (and/or creating) objects by simple queries without turning to SQL. They work by
# appending the name of an attribute to <tt>find_by_</tt>, <tt>find_last_by_</tt>, or <tt>find_all_by_</tt>, so you get finders like <tt>Person.find_by_user_name</tt>,
# <tt>Person.find_all_by_last_name</tt>, and <tt>Payment.find_by_transaction_id</tt>. So instead of writing
# <tt>Person.find(:first, :conditions => ["user_name = ?", user_name])</tt>, you just do <tt>Person.find_by_user_name(user_name)</tt>.
# And instead of writing <tt>Person.find(:all, :conditions => ["last_name = ?", last_name])</tt>, you just do <tt>Person.find_all_by_last_name(last_name)</tt>.
#
# It's also possible to use multiple attributes in the same find by separating them with "_and_", so you get finders like
# <tt>Person.find_by_user_name_and_password</tt> or even <tt>Payment.find_by_purchaser_and_state_and_country</tt>. So instead of writing
# <tt>Person.find(:first, :conditions => ["user_name = ? AND password = ?", user_name, password])</tt>, you just do
# <tt>Person.find_by_user_name_and_password(user_name, password)</tt>.
#
# It's even possible to use all the additional parameters to find. For example, the full interface for <tt>Payment.find_all_by_amount</tt>
# is actually <tt>Payment.find_all_by_amount(amount, options)</tt>. And the full interface to <tt>Person.find_by_user_name</tt> is
# actually <tt>Person.find_by_user_name(user_name, options)</tt>. So you could call <tt>Payment.find_all_by_amount(50, :order => "created_on")</tt>.
# Also you may call <tt>Payment.find_last_by_amount(amount, options)</tt> returning the last record matching that amount and options.
#
# The same dynamic finder style can be used to create the object if it doesn't already exist. This dynamic finder is called with
# <tt>find_or_create_by_</tt> and will return the object if it already exists and otherwise creates it, then returns it. Protected attributes won't be set unless they are given in a block. For example:
#
# # No 'Summer' tag exists
# Tag.find_or_create_by_name("Summer") # equal to Tag.create(:name => "Summer")
#
# # Now the 'Summer' tag does exist
# Tag.find_or_create_by_name("Summer") # equal to Tag.find_by_name("Summer")
#
# # Now 'Bob' exist and is an 'admin'
# User.find_or_create_by_name('Bob', :age => 40) { |u| u.admin = true }
#
# Use the <tt>find_or_initialize_by_</tt> finder if you want to return a new record without saving it first. Protected attributes won't be set unless they are given in a block. For example:
#
# # No 'Winter' tag exists
# winter = Tag.find_or_initialize_by_name("Winter")
# winter.new_record? # true
#
# To find by a subset of the attributes to be used for instantiating a new object, pass a hash instead of
# a list of parameters. For example:
#
# Tag.find_or_create_by_name(:name => "rails", :creator => current_user)
#
# That will either find an existing tag named "rails", or create a new one while setting the user that created it.
#
# == Saving arrays, hashes, and other non-mappable objects in text columns
#
# Active Record can serialize any object in text columns using YAML. To do so, you must specify this with a call to the class method +serialize+.
# This makes it possible to store arrays, hashes, and other non-mappable objects without doing any additional work. Example:
#
# class User < ActiveRecord::Base
# serialize :preferences
# end
#
# user = User.create(:preferences => { "background" => "black", "display" => large })
# User.find(user.id).preferences # => { "background" => "black", "display" => large }
#
# You can also specify a class option as the second parameter that'll raise an exception if a serialized object is retrieved as a
# descendant of a class not in the hierarchy. Example:
#
# class User < ActiveRecord::Base
# serialize :preferences, Hash
# end
#
# user = User.create(:preferences => %w( one two three ))
# User.find(user.id).preferences # raises SerializationTypeMismatch
#
# == Single table inheritance
#
# Active Record allows inheritance by storing the name of the class in a column that by default is named "type" (can be changed
# by overwriting <tt>Base.inheritance_column</tt>). This means that an inheritance looking like this:
#
# class Company < ActiveRecord::Base; end
# class Firm < Company; end
# class Client < Company; end
# class PriorityClient < Client; end
#
# When you do <tt>Firm.create(:name => "37signals")</tt>, this record will be saved in the companies table with type = "Firm". You can then
# fetch this row again using <tt>Company.find(:first, "name = '37signals'")</tt> and it will return a Firm object.
#
# If you don't have a type column defined in your table, single-table inheritance won't be triggered. In that case, it'll work just
# like normal subclasses with no special magic for differentiating between them or reloading the right type with find.
#
# Note, all the attributes for all the cases are kept in the same table. Read more:
# http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html
#
# == Connection to multiple databases in different models
#
# Connections are usually created through ActiveRecord::Base.establish_connection and retrieved by ActiveRecord::Base.connection.
# All classes inheriting from ActiveRecord::Base will use this connection. But you can also set a class-specific connection.
# For example, if Course is an ActiveRecord::Base, but resides in a different database, you can just say <tt>Course.establish_connection</tt>
# and Course and all of its subclasses will use this connection instead.
#
# This feature is implemented by keeping a connection pool in ActiveRecord::Base that is a Hash indexed by the class. If a connection is
# requested, the retrieve_connection method will go up the class-hierarchy until a connection is found in the connection pool.
#
# == Exceptions
#
# * ActiveRecordError - Generic error class and superclass of all other errors raised by Active Record.
# * AdapterNotSpecified - The configuration hash used in <tt>establish_connection</tt> didn't include an
# <tt>:adapter</tt> key.
# * AdapterNotFound - The <tt>:adapter</tt> key used in <tt>establish_connection</tt> specified a non-existent adapter
# (or a bad spelling of an existing one).
# * AssociationTypeMismatch - The object assigned to the association wasn't of the type specified in the association definition.
# * SerializationTypeMismatch - The serialized object wasn't of the class specified as the second parameter.
# * ConnectionNotEstablished+ - No connection has been established. Use <tt>establish_connection</tt> before querying.
# * RecordNotFound - No record responded to the +find+ method. Either the row with the given ID doesn't exist
# or the row didn't meet the additional restrictions. Some +find+ calls do not raise this exception to signal
# nothing was found, please check its documentation for further details.
# * StatementInvalid - The database server rejected the SQL statement. The precise error is added in the message.
# * MultiparameterAssignmentErrors - Collection of errors that occurred during a mass assignment using the
# <tt>attributes=</tt> method. The +errors+ property of this exception contains an array of AttributeAssignmentError
# objects that should be inspected to determine which attributes triggered the errors.
# * AttributeAssignmentError - An error occurred while doing a mass assignment through the <tt>attributes=</tt> method.
# You can inspect the +attribute+ property of the exception object to determine which attribute triggered the error.
#
# *Note*: The attributes listed are class-level attributes (accessible from both the class and instance level).
# So it's possible to assign a logger to the class through <tt>Base.logger=</tt> which will then be used by all
# instances in the current object space.
class Base
##
# :singleton-method:
# Accepts a logger conforming to the interface of Log4r or the default Ruby 1.8+ Logger class, which is then passed
# on to any new database connections made and which can be retrieved on both a class and instance level by calling +logger+.
cattr_accessor :logger, :instance_writer => false
def self.inherited(child) #:nodoc:
@@subclasses[self] ||= []
@@subclasses[self] << child
super
end
def self.reset_subclasses #:nodoc:
nonreloadables = []
subclasses.each do |klass|
unless ActiveSupport::Dependencies.autoloaded? klass
nonreloadables << klass
next
end
klass.instance_variables.each { |var| klass.send(:remove_instance_variable, var) }
klass.instance_methods(false).each { |m| klass.send :undef_method, m }
end
@@subclasses = {}
nonreloadables.each { |klass| (@@subclasses[klass.superclass] ||= []) << klass }
end
@@subclasses = {}
##
# :singleton-method:
# Contains the database configuration - as is typically stored in config/database.yml -
# as a Hash.
#
# For example, the following database.yml...
#
# development:
# adapter: sqlite3
# database: db/development.sqlite3
#
# production:
# adapter: sqlite3
# database: db/production.sqlite3
#
# ...would result in ActiveRecord::Base.configurations to look like this:
#
# {
# 'development' => {
# 'adapter' => 'sqlite3',
# 'database' => 'db/development.sqlite3'
# },
# 'production' => {
# 'adapter' => 'sqlite3',
# 'database' => 'db/production.sqlite3'
# }
# }
cattr_accessor :configurations, :instance_writer => false
@@configurations = {}
##
# :singleton-method:
# Accessor for the prefix type that will be prepended to every primary key column name. The options are :table_name and
# :table_name_with_underscore. If the first is specified, the Product class will look for "productid" instead of "id" as
# the primary column. If the latter is specified, the Product class will look for "product_id" instead of "id". Remember
# that this is a global setting for all Active Records.
cattr_accessor :primary_key_prefix_type, :instance_writer => false
@@primary_key_prefix_type = nil
##
# :singleton-method:
# Accessor for the name of the prefix string to prepend to every table name. So if set to "basecamp_", all
# table names will be named like "basecamp_projects", "basecamp_people", etc. This is a convenient way of creating a namespace
# for tables in a shared database. By default, the prefix is the empty string.
cattr_accessor :table_name_prefix, :instance_writer => false
@@table_name_prefix = ""
##
# :singleton-method:
# Works like +table_name_prefix+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp",
# "people_basecamp"). By default, the suffix is the empty string.
cattr_accessor :table_name_suffix, :instance_writer => false
@@table_name_suffix = ""
##
# :singleton-method:
# Indicates whether table names should be the pluralized versions of the corresponding class names.
# If true, the default table name for a Product class will be +products+. If false, it would just be +product+.
# See table_name for the full rules on table/class naming. This is true, by default.
cattr_accessor :pluralize_table_names, :instance_writer => false
@@pluralize_table_names = true
##
# :singleton-method:
# Determines whether to use ANSI codes to colorize the logging statements committed by the connection adapter. These colors
# make it much easier to overview things during debugging (when used through a reader like +tail+ and on a black background), but
# may complicate matters if you use software like syslog. This is true, by default.
cattr_accessor :colorize_logging, :instance_writer => false
@@colorize_logging = true
##
# :singleton-method:
# Determines whether to use Time.local (using :local) or Time.utc (using :utc) when pulling dates and times from the database.
# This is set to :local by default.
cattr_accessor :default_timezone, :instance_writer => false
@@default_timezone = :local
##
# :singleton-method:
# Specifies the format to use when dumping the database schema with Rails'
# Rakefile. If :sql, the schema is dumped as (potentially database-
# specific) SQL statements. If :ruby, the schema is dumped as an
# ActiveRecord::Schema file which can be loaded into any database that
# supports migrations. Use :ruby if you want to have different database
# adapters for, e.g., your development and test environments.
cattr_accessor :schema_format , :instance_writer => false
@@schema_format = :ruby
##
# :singleton-method:
# Specify whether or not to use timestamps for migration numbers
cattr_accessor :timestamped_migrations , :instance_writer => false
@@timestamped_migrations = true
# Determine whether to store the full constant name including namespace when using STI
superclass_delegating_accessor :store_full_sti_class
self.store_full_sti_class = false
# Stores the default scope for the class
class_inheritable_accessor :default_scoping, :instance_writer => false
self.default_scoping = []
class << self # Class methods
# Find operates with four different retrieval approaches:
#
# * Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]).
# If no record can be found for all of the listed ids, then RecordNotFound will be raised.
# * Find first - This will return the first record matched by the options used. These options can either be specific
# conditions or merely an order. If no record can be matched, +nil+ is returned. Use
# <tt>Model.find(:first, *args)</tt> or its shortcut <tt>Model.first(*args)</tt>.
# * Find last - This will return the last record matched by the options used. These options can either be specific
# conditions or merely an order. If no record can be matched, +nil+ is returned. Use
# <tt>Model.find(:last, *args)</tt> or its shortcut <tt>Model.last(*args)</tt>.
# * Find all - This will return all the records matched by the options used.
# If no records are found, an empty array is returned. Use
# <tt>Model.find(:all, *args)</tt> or its shortcut <tt>Model.all(*args)</tt>.
#
# All approaches accept an options hash as their last parameter.
#
# ==== Parameters
#
# * <tt>:conditions</tt> - An SQL fragment like "administrator = 1", <tt>[ "user_name = ?", username ]</tt>, or <tt>["user_name = :user_name", { :user_name => user_name }]</tt>. See conditions in the intro.
# * <tt>:order</tt> - An SQL fragment like "created_at DESC, name".
# * <tt>:group</tt> - An attribute name by which the result should be grouped. Uses the <tt>GROUP BY</tt> SQL-clause.
# * <tt>:having</tt> - Combined with +:group+ this can be used to filter the records that a <tt>GROUP BY</tt> returns. Uses the <tt>HAVING</tt> SQL-clause.
# * <tt>:limit</tt> - An integer determining the limit on the number of rows that should be returned.
# * <tt>:offset</tt> - An integer determining the offset from where the rows should be fetched. So at 5, it would skip rows 0 through 4.
# * <tt>:joins</tt> - Either an SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id" (rarely needed),
# named associations in the same form used for the <tt>:include</tt> option, which will perform an <tt>INNER JOIN</tt> on the associated table(s),
# or an array containing a mixture of both strings and named associations.
# If the value is a string, then the records will be returned read-only since they will have attributes that do not correspond to the table's columns.
# Pass <tt>:readonly => false</tt> to override.
# * <tt>:include</tt> - Names associations that should be loaded alongside. The symbols named refer
# to already defined associations. See eager loading under Associations.
# * <tt>:select</tt> - By default, this is "*" as in "SELECT * FROM", but can be changed if you, for example, want to do a join but not
# include the joined columns. Takes a string with the SELECT SQL fragment (e.g. "id, name").
# * <tt>:from</tt> - By default, this is the table name of the class, but can be changed to an alternate table name (or even the name
# of a database view).
# * <tt>:readonly</tt> - Mark the returned records read-only so they cannot be saved or updated.
# * <tt>:lock</tt> - An SQL fragment like "FOR UPDATE" or "LOCK IN SHARE MODE".
# <tt>:lock => true</tt> gives connection's default exclusive lock, usually "FOR UPDATE".
#
# ==== Examples
#
# # find by id
# Person.find(1) # returns the object for ID = 1
# Person.find(1, 2, 6) # returns an array for objects with IDs in (1, 2, 6)
# Person.find([7, 17]) # returns an array for objects with IDs in (7, 17)
# Person.find([1]) # returns an array for the object with ID = 1
# Person.find(1, :conditions => "administrator = 1", :order => "created_on DESC")
#
# Note that returned records may not be in the same order as the ids you
# provide since database rows are unordered. Give an explicit <tt>:order</tt>
# to ensure the results are sorted.
#
# ==== Examples
#
# # find first
# Person.find(:first) # returns the first object fetched by SELECT * FROM people
# Person.find(:first, :conditions => [ "user_name = ?", user_name])
# Person.find(:first, :conditions => [ "user_name = :u", { :u => user_name }])
# Person.find(:first, :order => "created_on DESC", :offset => 5)
#
# # find last
# Person.find(:last) # returns the last object fetched by SELECT * FROM people
# Person.find(:last, :conditions => [ "user_name = ?", user_name])
# Person.find(:last, :order => "created_on DESC", :offset => 5)
#
# # find all
# Person.find(:all) # returns an array of objects for all the rows fetched by SELECT * FROM people
# Person.find(:all, :conditions => [ "category IN (?)", categories], :limit => 50)
# Person.find(:all, :conditions => { :friends => ["Bob", "Steve", "Fred"] }
# Person.find(:all, :offset => 10, :limit => 10)
# Person.find(:all, :include => [ :account, :friends ])
# Person.find(:all, :group => "category")
#
# Example for find with a lock: Imagine two concurrent transactions:
# each will read <tt>person.visits == 2</tt>, add 1 to it, and save, resulting
# in two saves of <tt>person.visits = 3</tt>. By locking the row, the second
# transaction has to wait until the first is finished; we get the
# expected <tt>person.visits == 4</tt>.
#
# Person.transaction do
# person = Person.find(1, :lock => true)
# person.visits += 1
# person.save!
# end
def find(*args)
options = args.extract_options!
validate_find_options(options)
set_readonly_option!(options)
case args.first
when :first then find_initial(options)
when :last then find_last(options)
when :all then find_every(options)
else find_from_ids(args, options)
end
end
# A convenience wrapper for <tt>find(:first, *args)</tt>. You can pass in all the
# same arguments to this method as you can to <tt>find(:first)</tt>.
def first(*args)
find(:first, *args)
end
# A convenience wrapper for <tt>find(:last, *args)</tt>. You can pass in all the
# same arguments to this method as you can to <tt>find(:last)</tt>.
def last(*args)
find(:last, *args)
end
# This is an alias for find(:all). You can pass in all the same arguments to this method as you can
# to find(:all)
def all(*args)
find(:all, *args)
end
# Executes a custom SQL query against your database and returns all the results. The results will
# be returned as an array with columns requested encapsulated as attributes of the model you call
# this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in
# a Product object with the attributes you specified in the SQL query.
#
# If you call a complicated SQL query which spans multiple tables the columns specified by the
# SELECT will be attributes of the model, whether or not they are columns of the corresponding
# table.
#
# The +sql+ parameter is a full SQL query as a string. It will be called as is, there will be
# no database agnostic conversions performed. This should be a last resort because using, for example,
# MySQL specific terms will lock you to using that particular database engine or require you to
# change your call if you switch engines.
#
# ==== Examples
# # A simple SQL query spanning multiple tables
# Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id"
# > [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...]
#
# # You can use the same string replacement techniques as you can with ActiveRecord#find
# Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date]
# > [#<Post:0x36bff9c @attributes={"first_name"=>"The Cheap Man Buys Twice"}>, ...]
def find_by_sql(sql)
connection.select_all(sanitize_sql(sql), "#{name} Load").collect! { |record| instantiate(record) }
end
# Returns true if a record exists in the table that matches the +id+ or
# conditions given, or false otherwise. The argument can take five forms:
#
# * Integer - Finds the record with this primary key.
# * String - Finds the record with a primary key corresponding to this
# string (such as <tt>'5'</tt>).
# * Array - Finds the record that matches these +find+-style conditions
# (such as <tt>['color = ?', 'red']</tt>).
# * Hash - Finds the record that matches these +find+-style conditions
# (such as <tt>{:color => 'red'}</tt>).
# * No args - Returns false if the table is empty, true otherwise.
#
# For more information about specifying conditions as a Hash or Array,
# see the Conditions section in the introduction to ActiveRecord::Base.
#
# Note: You can't pass in a condition as a string (like <tt>name =
# 'Jamie'</tt>), since it would be sanitized and then queried against
# the primary key column, like <tt>id = 'name = \'Jamie\''</tt>.
#
# ==== Examples
# Person.exists?(5)
# Person.exists?('5')
# Person.exists?(:name => "David")
# Person.exists?(['name LIKE ?', "%#{query}%"])
# Person.exists?
def exists?(id_or_conditions = {})
find_initial(
:select => "#{quoted_table_name}.#{primary_key}",
:conditions => expand_id_conditions(id_or_conditions)) ? true : false
end
# Creates 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.
#
# The +attributes+ parameter can be either be a Hash or an Array of Hashes. These Hashes describe the
# attributes on the objects that are to be created.
#
# ==== Examples
# # Create a single new object
# User.create(:first_name => 'Jamie')
#
# # Create an Array of new objects
# User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }])
#
# # Create a single object and pass it into a block to set other attributes.
# User.create(:first_name => 'Jamie') do |u|
# u.is_admin = false
# end
#
# # Creating an Array of new objects using a block, where the block is executed for each object:
# User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }]) do |u|
# u.is_admin = false
# end
def create(attributes = nil, &block)
if attributes.is_a?(Array)
attributes.collect { |attr| create(attr, &block) }
else
object = new(attributes)
yield(object) if block_given?
object.save
object
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 to be set on the object, or an array of hashes.
#
# ==== Examples
#
# # Updating one record:
# Person.update(15, :user_name => 'Samuel', :group => 'expert')
#
# # Updating 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
# 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)
delete_all([ "#{connection.quote_column_name(primary_key)} IN (?)", id ])
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
# 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 our 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 = {})
sql = "UPDATE #{quoted_table_name} SET #{sanitize_sql_for_assignment(updates)} "
scope = scope(:find)
select_sql = ""
add_conditions!(select_sql, conditions, scope)
if options.has_key?(:limit) || (scope && scope[:limit])
# Only take order from scope if limit is also provided by scope, this
# is useful for updating a has_many association with a limit.
add_order!(select_sql, options[:order], scope)
add_limit!(select_sql, options, scope)
sql.concat(connection.limited_update_conditions(select_sql, quoted_table_name, connection.quote_column_name(primary_key)))
else
add_order!(select_sql, options[:order], nil)
sql.concat(select_sql)
end
connection.update(sql, "#{name} Update")
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)
find(:all, :conditions => conditions).each { |object| object.destroy }
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)
sql = "DELETE FROM #{quoted_table_name} "
add_conditions!(sql, conditions, scope(:find))
connection.delete(sql, "#{name} Delete all")
end
# Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part.
# The use of this method should be restricted to complicated SQL queries that can't be executed
# using the ActiveRecord::Calculations class methods. Look into those before using this.
#
# ==== Parameters
#
# * +sql+ - An SQL statement which should return a count query from the database, see the example below.
#
# ==== Examples
#
# Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
def count_by_sql(sql)
sql = sanitize_conditions(sql)
connection.select_value(sql, "#{name} Count").to_i
end
# A generic "counter updater" implementation, intended primarily to be
# used by increment_counter and decrement_counter, but which may also
# be useful on its own. It simply does a direct SQL update for the record
# with the given ID, altering the given hash of counters by the amount
# given by the corresponding value:
#
# ==== Parameters
#
# * +id+ - The id of the object you wish to update a counter on or an Array of ids.
# * +counters+ - An Array of Hashes containing the names of the fields
# to update as keys and the amount to update the field by as values.
#
# ==== Examples
#
# # For the Post with id of 5, decrement the comment_count by 1, and
# # increment the action_count by 1
# Post.update_counters 5, :comment_count => -1, :action_count => 1
# # Executes the following SQL:
# # UPDATE posts
# # SET comment_count = comment_count - 1,
# # action_count = action_count + 1
# # WHERE id = 5
#
# # For the Posts with id of 10 and 15, increment the comment_count by 1
# Post.update_counters [10, 15], :comment_count => 1
# # Executes the following SQL:
# # UPDATE posts
# # SET comment_count = comment_count + 1,
# # WHERE id IN (10, 15)
def update_counters(id, counters)
updates = counters.inject([]) { |list, (counter_name, increment)|
sign = increment < 0 ? "-" : "+"
list << "#{connection.quote_column_name(counter_name)} = COALESCE(#{connection.quote_column_name(counter_name)}, 0) #{sign} #{increment.abs}"
}.join(", ")
if id.is_a?(Array)
ids_list = id.map {|i| quote_value(i)}.join(', ')
condition = "IN (#{ids_list})"
else
condition = "= #{quote_value(id)}"
end
update_all(updates, "#{connection.quote_column_name(primary_key)} #{condition}")
end
# Increment a number field by one, usually representing a count.
#
# This is used for caching aggregate values, so that they don't need to be computed every time.
# For example, a DiscussionBoard may cache post_count and comment_count otherwise every time the board is
# shown it would have to run an SQL query to find how many posts and comments there are.
#
# ==== Parameters
#
# * +counter_name+ - The name of the field that should be incremented.
# * +id+ - The id of the object that should be incremented.
#
# ==== Examples
#
# # Increment the post_count column for the record with an id of 5
# DiscussionBoard.increment_counter(:post_count, 5)
def increment_counter(counter_name, id)
update_counters(id, counter_name => 1)
end
# Decrement a number field by one, usually representing a count.
#
# This works the same as increment_counter but reduces the column value by 1 instead of increasing it.
#
# ==== Parameters
#
# * +counter_name+ - The name of the field that should be decremented.
# * +id+ - The id of the object that should be decremented.
#
# ==== Examples
#
# # Decrement the post_count column for the record with an id of 5
# DiscussionBoard.decrement_counter(:post_count, 5)
def decrement_counter(counter_name, id)
update_counters(id, counter_name => -1)
end
# Attributes named in this macro are protected from mass-assignment,
# such as <tt>new(attributes)</tt>,
# <tt>update_attributes(attributes)</tt>, or
# <tt>attributes=(attributes)</tt>.
#
# Mass-assignment to these attributes will simply be ignored, to assign
# to them you can use direct writer methods. This is meant to protect
# sensitive attributes from being overwritten by malicious users
# tampering with URLs or forms.
#
# class Customer < ActiveRecord::Base
# attr_protected :credit_rating
# end
#
# customer = Customer.new("name" => David, "credit_rating" => "Excellent")
# customer.credit_rating # => nil
# customer.attributes = { "description" => "Jolly fellow", "credit_rating" => "Superb" }
# customer.credit_rating # => nil
#
# customer.credit_rating = "Average"
# customer.credit_rating # => "Average"
#
# To start from an all-closed default and enable attributes as needed,
# have a look at +attr_accessible+.
def attr_protected(*attributes)
write_inheritable_attribute(:attr_protected, Set.new(attributes.map {|a| a.to_s}) + (protected_attributes || []))
end
# Returns an array of all the attributes that have been protected from mass-assignment.
def protected_attributes # :nodoc:
read_inheritable_attribute(:attr_protected)
end
# Specifies a white list of model attributes that can be set via
# mass-assignment, such as <tt>new(attributes)</tt>,
# <tt>update_attributes(attributes)</tt>, or
# <tt>attributes=(attributes)</tt>
#
# This is the opposite of the +attr_protected+ macro: Mass-assignment
# will only set attributes in this list, to assign to the rest of
# attributes you can use direct writer methods. This is meant to protect
# sensitive attributes from being overwritten by malicious users
# tampering with URLs or forms. If you'd rather start from an all-open
# default and restrict attributes as needed, have a look at
# +attr_protected+.
#
# class Customer < ActiveRecord::Base
# attr_accessible :name, :nickname
# end
#
# customer = Customer.new(:name => "David", :nickname => "Dave", :credit_rating => "Excellent")
# customer.credit_rating # => nil
# customer.attributes = { :name => "Jolly fellow", :credit_rating => "Superb" }
# customer.credit_rating # => nil
#
# customer.credit_rating = "Average"
# customer.credit_rating # => "Average"
def attr_accessible(*attributes)
write_inheritable_attribute(:attr_accessible, Set.new(attributes.map(&:to_s)) + (accessible_attributes || []))
end
# Returns an array of all the attributes that have been made accessible to mass-assignment.
def accessible_attributes # :nodoc:
read_inheritable_attribute(:attr_accessible)
end
# Attributes listed as readonly can be set for a new record, but will be ignored in database updates afterwards.
def attr_readonly(*attributes)
write_inheritable_attribute(:attr_readonly, Set.new(attributes.map(&:to_s)) + (readonly_attributes || []))
end
# Returns an array of all the attributes that have been specified as readonly.
def readonly_attributes
read_inheritable_attribute(:attr_readonly)
end
# If you have an attribute that needs to be saved to the database as an object, and retrieved as the same object,
# then specify the name of that attribute using this method and it will be handled automatically.
# The serialization is done through YAML. If +class_name+ is specified, the serialized object must be of that
# class on retrieval or SerializationTypeMismatch will be raised.
#
# ==== Parameters
#
# * +attr_name+ - The field name that should be serialized.
# * +class_name+ - Optional, class name that the object type should be equal to.
#
# ==== Example
# # Serialize a preferences attribute
# class User
# serialize :preferences
# end
def serialize(attr_name, class_name = Object)
serialized_attributes[attr_name.to_s] = class_name
end
# Returns a hash of all the attributes that have been specified for serialization as keys and their class restriction as values.
def serialized_attributes
read_inheritable_attribute(:attr_serialized) or write_inheritable_attribute(:attr_serialized, {})
end
# Guesses the table name (in forced lower-case) based on the name of the class in the inheritance hierarchy descending
# directly from ActiveRecord::Base. So if the hierarchy looks like: Reply < Message < ActiveRecord::Base, then Message is used
# to guess the table name even when called on Reply. The rules used to do the guess are handled by the Inflector class
# in Active Support, which knows almost all common English inflections. You can add new inflections in config/initializers/inflections.rb.
#
# Nested classes are given table names prefixed by the singular form of
# the parent's table name. Enclosing modules are not considered.
#
# ==== Examples
#
# class Invoice < ActiveRecord::Base; end;
# file class table_name
# invoice.rb Invoice invoices
#
# class Invoice < ActiveRecord::Base; class Lineitem < ActiveRecord::Base; end; end;
# file class table_name
# invoice.rb Invoice::Lineitem invoice_lineitems
#
# module Invoice; class Lineitem < ActiveRecord::Base; end; end;
# file class table_name
# invoice/lineitem.rb Invoice::Lineitem lineitems
#
# Additionally, the class-level +table_name_prefix+ is prepended and the
# +table_name_suffix+ is appended. So if you have "myapp_" as a prefix,
# the table name guess for an Invoice class becomes "myapp_invoices".
# Invoice::Lineitem becomes "myapp_invoice_lineitems".
#
# You can also overwrite this class method to allow for unguessable
# links, such as a Mouse class with a link to a "mice" table. Example:
#
# class Mouse < ActiveRecord::Base
# set_table_name "mice"
# end
def table_name
reset_table_name
end
def reset_table_name #:nodoc:
base = base_class
name =
# STI subclasses always use their superclass' table.
unless self == base
base.table_name
else
# Nested classes are prefixed with singular parent table name.
if parent < ActiveRecord::Base && !parent.abstract_class?
contained = parent.table_name
contained = contained.singularize if parent.pluralize_table_names
contained << '_'
end
name = "#{table_name_prefix}#{contained}#{undecorated_table_name(base.name)}#{table_name_suffix}"
end
set_table_name(name)
name
end
# Defines the primary key field -- can be overridden in subclasses. Overwriting will negate any effect of the
# primary_key_prefix_type setting, though.
def primary_key
reset_primary_key
end
def reset_primary_key #:nodoc:
key = get_primary_key(base_class.name)
set_primary_key(key)
key
end
def get_primary_key(base_name) #:nodoc:
key = 'id'
case primary_key_prefix_type
when :table_name
key = base_name.to_s.foreign_key(false)
when :table_name_with_underscore
key = base_name.to_s.foreign_key
end
key
end
# Defines the column name for use with single table inheritance
# -- can be set in subclasses like so: self.inheritance_column = "type_id"
def inheritance_column
@inheritance_column ||= "type".freeze
end
# Lazy-set the sequence name to the connection's default. This method
# is only ever called once since set_sequence_name overrides it.
def sequence_name #:nodoc:
reset_sequence_name
end
def reset_sequence_name #:nodoc:
default = connection.default_sequence_name(table_name, primary_key)
set_sequence_name(default)
default
end
# Sets the table name to use to the given value, or (if the value
# is nil or false) to the value returned by the given block.
#
# class Project < ActiveRecord::Base
# set_table_name "project"
# end
def set_table_name(value = nil, &block)
define_attr_method :table_name, value, &block
end
alias :table_name= :set_table_name
# Sets the name of the primary key column to use to the given value,
# or (if the value is nil or false) to the value returned by the given
# block.
#
# class Project < ActiveRecord::Base
# set_primary_key "sysid"
# end
def set_primary_key(value = nil, &block)
define_attr_method :primary_key, value, &block
end
alias :primary_key= :set_primary_key
# Sets the name of the inheritance column to use to the given value,
# or (if the value # is nil or false) to the value returned by the
# given block.
#
# class Project < ActiveRecord::Base
# set_inheritance_column do
# original_inheritance_column + "_id"
# end
# end
def set_inheritance_column(value = nil, &block)
define_attr_method :inheritance_column, value, &block
end
alias :inheritance_column= :set_inheritance_column
# Sets the name of the sequence to use when generating ids to the given
# value, or (if the value is nil or false) to the value returned by the
# given block. This is required for Oracle and is useful for any
# database which relies on sequences for primary key generation.
#
# If a sequence name is not explicitly set when using Oracle or Firebird,
# it will default to the commonly used pattern of: #{table_name}_seq
#
# If a sequence name is not explicitly set when using PostgreSQL, it
# will discover the sequence corresponding to your primary key for you.
#
# class Project < ActiveRecord::Base
# set_sequence_name "projectseq" # default would have been "project_seq"
# end
def set_sequence_name(value = nil, &block)
define_attr_method :sequence_name, value, &block
end
alias :sequence_name= :set_sequence_name
# Turns the +table_name+ back into a class name following the reverse rules of +table_name+.
def class_name(table_name = table_name) # :nodoc:
# remove any prefix and/or suffix from the table name
class_name = table_name[table_name_prefix.length..-(table_name_suffix.length + 1)].camelize
class_name = class_name.singularize if pluralize_table_names
class_name
end
# Indicates whether the table associated with this class exists
def table_exists?
connection.table_exists?(table_name)
end
# Returns an array of column objects for the table associated with this class.
def columns
unless defined?(@columns) && @columns
@columns = connection.columns(table_name, "#{name} Columns")
@columns.each { |column| column.primary = column.name == primary_key }
end
@columns
end
# Returns a hash of column objects for the table associated with this class.
def columns_hash
@columns_hash ||= columns.inject({}) { |hash, column| hash[column.name] = column; hash }
end
# Returns an array of column names as strings.
def column_names
@column_names ||= columns.map { |column| column.name }
end
# Returns an array of column objects where the primary id, all columns ending in "_id" or "_count",
# and columns used for single table inheritance have been removed.
def content_columns
@content_columns ||= columns.reject { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column }
end
# Returns a hash of all the methods added to query each of the columns in the table with the name of the method as the key
# and true as the value. This makes it possible to do O(1) lookups in respond_to? to check if a given method for attribute
# is available.
def column_methods_hash #:nodoc:
@dynamic_methods_hash ||= column_names.inject(Hash.new(false)) do |methods, attr|
attr_name = attr.to_s
methods[attr.to_sym] = attr_name
methods["#{attr}=".to_sym] = attr_name
methods["#{attr}?".to_sym] = attr_name
methods["#{attr}_before_type_cast".to_sym] = attr_name
methods
end
end
# Resets all the cached information about columns, which will cause them
# to be reloaded on the next request.
#
# The most common usage pattern for this method is probably in a migration,
# when just after creating a table you want to populate it with some default
# values, eg:
#
# class CreateJobLevels < ActiveRecord::Migration
# def self.up
# create_table :job_levels do |t|
# t.integer :id
# t.string :name
#
# t.timestamps
# end
#
# JobLevel.reset_column_information
# %w{assistant executive manager director}.each do |type|
# JobLevel.create(:name => type)
# end
# end
#
# def self.down
# drop_table :job_levels
# end
# end
def reset_column_information
generated_methods.each { |name| undef_method(name) }
@column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @generated_methods = @inheritance_column = nil
end
def reset_column_information_and_inheritable_attributes_for_all_subclasses#:nodoc:
subclasses.each { |klass| klass.reset_inheritable_attributes; klass.reset_column_information }
end
def self_and_descendants_from_active_record#nodoc:
klass = self
classes = [klass]
while klass != klass.base_class
classes << klass = klass.superclass
end
classes
rescue
# OPTIMIZE this rescue is to fix this test: ./test/cases/reflection_test.rb:56:in `test_human_name_for_column'
# Appearantly the method base_class causes some trouble.
# It now works for sure.
[self]
end
# Transforms attribute key names into a more humane format, such as "First name" instead of "first_name". Example:
# Person.human_attribute_name("first_name") # => "First name"
# This used to be depricated in favor of humanize, but is now preferred, because it automatically uses the I18n
# module now.
# Specify +options+ with additional translating options.
def human_attribute_name(attribute_key_name, options = {})
defaults = self_and_descendants_from_active_record.map do |klass|
:"#{klass.name.underscore}.#{attribute_key_name}"
end
defaults << options[:default] if options[:default]
defaults.flatten!
defaults << attribute_key_name.humanize
options[:count] ||= 1
I18n.translate(defaults.shift, options.merge(:default => defaults, :scope => [:activerecord, :attributes]))
end
# Transform the modelname into a more humane format, using I18n.
# By default, it will underscore then humanize the class name (BlogPost.human_name #=> "Blog post").
# Default scope of the translation is activerecord.models
# Specify +options+ with additional translating options.
def human_name(options = {})
defaults = self_and_descendants_from_active_record.map do |klass|
:"#{klass.name.underscore}"
end
defaults << self.name.underscore.humanize
I18n.translate(defaults.shift, {:scope => [:activerecord, :models], :count => 1, :default => defaults}.merge(options))
end
# True if this isn't a concrete subclass needing a STI type condition.
def descends_from_active_record?
if superclass.abstract_class?
superclass.descends_from_active_record?
else
superclass == Base || !columns_hash.include?(inheritance_column)
end
end
def finder_needs_type_condition? #:nodoc:
# This is like this because benchmarking justifies the strange :false stuff
:true == (@finder_needs_type_condition ||= descends_from_active_record? ? :false : :true)
end
# Returns a string like 'Post id:integer, title:string, body:text'
def inspect
if self == Base
super
elsif abstract_class?
"#{super}(abstract)"
elsif table_exists?
attr_list = columns.map { |c| "#{c.name}: #{c.type}" } * ', '
"#{super}(#{attr_list})"
else
"#{super}(Table doesn't exist)"
end
end
def quote_value(value, column = nil) #:nodoc:
connection.quote(value,column)
end
# Used to sanitize objects before they're used in an SQL SELECT statement. Delegates to <tt>connection.quote</tt>.
def sanitize(object) #:nodoc:
connection.quote(object)
end
# Log and benchmark multiple statements in a single block. Example:
#
# Project.benchmark("Creating project") do
# project = Project.create("name" => "stuff")
# project.create_manager("name" => "David")
# project.milestones << Milestone.find(:all)
# end
#
# The benchmark is only recorded if the current level of the logger is less than or equal to the <tt>log_level</tt>,
# which makes it easy to include benchmarking statements in production software that will remain inexpensive because
# the benchmark will only be conducted if the log level is low enough.
#
# The logging of the multiple statements is turned off unless <tt>use_silence</tt> is set to false.
def benchmark(title, log_level = Logger::DEBUG, use_silence = true)
if logger && logger.level <= log_level
result = nil
ms = Benchmark.ms { result = use_silence ? silence { yield } : yield }
logger.add(log_level, '%s (%.1fms)' % [title, ms])
result
else
yield
end
end
# Silences the logger for the duration of the block.
def silence
old_logger_level, logger.level = logger.level, Logger::ERROR if logger
yield
ensure
logger.level = old_logger_level if logger
end
# Overwrite the default class equality method to provide support for association proxies.
def ===(object)
object.is_a?(self)
end
# Returns the base AR subclass that this class descends from. If A
# extends AR::Base, A.base_class will return A. If B descends from A
# through some arbitrarily deep hierarchy, B.base_class will return A.
def base_class
class_of_active_record_descendant(self)
end
# Set this to true if this is an abstract class (see <tt>abstract_class?</tt>).
attr_accessor :abstract_class
# Returns whether this class is a base AR class. If A is a base class and
# B descends from A, then B.base_class will return B.
def abstract_class?
defined?(@abstract_class) && @abstract_class == true
end
def respond_to?(method_id, include_private = false)
if match = DynamicFinderMatch.match(method_id)
return true if all_attributes_exists?(match.attribute_names)
elsif match = DynamicScopeMatch.match(method_id)
return true if all_attributes_exists?(match.attribute_names)
end
super
end
def sti_name
store_full_sti_class ? name : name.demodulize
end
# Merges conditions so that the result is a valid +condition+
def merge_conditions(*conditions)
segments = []
conditions.each do |condition|
unless condition.blank?
sql = sanitize_sql(condition)
segments << sql unless sql.blank?
end
end
"(#{segments.join(') AND (')})" unless segments.empty?
end
private
def find_initial(options)
options.update(:limit => 1)
find_every(options).first
end
def find_last(options)
order = options[:order]
if order
order = reverse_sql_order(order)
elsif !scoped?(:find, :order)
order = "#{table_name}.#{primary_key} DESC"
end
if scoped?(:find, :order)
scope = scope(:find)
original_scoped_order = scope[:order]
scope[:order] = reverse_sql_order(original_scoped_order)
end
begin
find_initial(options.merge({ :order => order }))
ensure
scope[:order] = original_scoped_order if original_scoped_order
end
end
def reverse_sql_order(order_query)
order_query.to_s.split(/,/).each { |s|
if s.match(/\s(asc|ASC)$/)
s.gsub!(/\s(asc|ASC)$/, ' DESC')
elsif s.match(/\s(desc|DESC)$/)
s.gsub!(/\s(desc|DESC)$/, ' ASC')
else
s.concat(' DESC')
end
}.join(',')
end
def find_every(options)
include_associations = merge_includes(scope(:find, :include), options[:include])
if include_associations.any? && references_eager_loaded_tables?(options)
records = find_with_associations(options)
else
records = find_by_sql(construct_finder_sql(options))
if include_associations.any?
preload_associations(records, include_associations)
end
end
records.each { |record| record.readonly! } if options[:readonly]
records
end
def find_from_ids(ids, options)
expects_array = ids.first.kind_of?(Array)
return ids.first if expects_array && ids.first.empty?
ids = ids.flatten.compact.uniq
case ids.size
when 0
raise RecordNotFound, "Couldn't find #{name} without an ID"
when 1
result = find_one(ids.first, options)
expects_array ? [ result ] : result
else
find_some(ids, options)
end
end
def find_one(id, options)
conditions = " AND (#{sanitize_sql(options[:conditions])})" if options[:conditions]
options.update :conditions => "#{quoted_table_name}.#{connection.quote_column_name(primary_key)} = #{quote_value(id,columns_hash[primary_key])}#{conditions}"
# Use find_every(options).first since the primary key condition
# already ensures we have a single record. Using find_initial adds
# a superfluous :limit => 1.
if result = find_every(options).first
result
else
raise RecordNotFound, "Couldn't find #{name} with ID=#{id}#{conditions}"
end
end
def find_some(ids, options)
conditions = " AND (#{sanitize_sql(options[:conditions])})" if options[:conditions]
ids_list = ids.map { |id| quote_value(id,columns_hash[primary_key]) }.join(',')
options.update :conditions => "#{quoted_table_name}.#{connection.quote_column_name(primary_key)} IN (#{ids_list})#{conditions}"
result = find_every(options)
# Determine expected size from limit and offset, not just ids.size.
expected_size =
if options[:limit] && ids.size > options[:limit]
options[:limit]
else
ids.size
end
# 11 ids with limit 3, offset 9 should give 2 results.
if options[:offset] && (ids.size - options[:offset] < expected_size)
expected_size = ids.size - options[:offset]
end
if result.size == expected_size
result
else
raise RecordNotFound, "Couldn't find all #{name.pluralize} with IDs (#{ids_list})#{conditions} (found #{result.size} results, but was looking for #{expected_size})"
end
end
# Finder methods must instantiate through this method to work with the
# single-table inheritance model that makes it possible to create
# objects of different types from the same table.
def instantiate(record)
object =
if subclass_name = record[inheritance_column]
# No type given.
if subclass_name.empty?
allocate
else
# Ignore type if no column is present since it was probably
# pulled in from a sloppy join.
unless columns_hash.include?(inheritance_column)
allocate
else
begin
compute_type(subclass_name).allocate
rescue NameError
raise SubclassNotFound,
"The single-table inheritance mechanism failed to locate the subclass: '#{record[inheritance_column]}'. " +
"This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
"Please rename this column if you didn't intend it to be used for storing the inheritance class " +
"or overwrite #{self.to_s}.inheritance_column to use another column for that information."
end
end
end
else
allocate
end
object.instance_variable_set("@attributes", record)
object.instance_variable_set("@attributes_cache", Hash.new)
if object.respond_to_without_attributes?(:after_find)
object.send(:callback, :after_find)
end
if object.respond_to_without_attributes?(:after_initialize)
object.send(:callback, :after_initialize)
end
object
end
# Nest the type name in the same module as this class.
# Bar is "MyApp::Business::Bar" relative to MyApp::Business::Foo
def type_name_with_module(type_name)
if store_full_sti_class
type_name
else
(/^::/ =~ type_name) ? type_name : "#{parent.name}::#{type_name}"
end
end
def default_select(qualified)
if qualified
quoted_table_name + '.*'
else
'*'
end
end
def construct_finder_sql(options)
scope = scope(:find)
sql = "SELECT #{options[:select] || (scope && scope[:select]) || default_select(options[:joins] || (scope && scope[:joins]))} "
sql << "FROM #{options[:from] || (scope && scope[:from]) || quoted_table_name} "
add_joins!(sql, options[:joins], scope)
add_conditions!(sql, options[:conditions], scope)
add_group!(sql, options[:group], options[:having], scope)
add_order!(sql, options[:order], scope)
add_limit!(sql, options, scope)
add_lock!(sql, options, scope)
sql
end
# Merges includes so that the result is a valid +include+
def merge_includes(first, second)
(safe_to_array(first) + safe_to_array(second)).uniq
end
def merge_joins(*joins)
if joins.any?{|j| j.is_a?(String) || array_of_strings?(j) }
joins = joins.collect do |join|
join = [join] if join.is_a?(String)
unless array_of_strings?(join)
join_dependency = ActiveRecord::Associations::ClassMethods::InnerJoinDependency.new(self, join, nil)
join = join_dependency.join_associations.collect { |assoc| assoc.association_join }
end
join
end
joins.flatten.map{|j| j.strip}.uniq
else
joins.collect{|j| safe_to_array(j)}.flatten.uniq
end
end
# Object#to_a is deprecated, though it does have the desired behavior
def safe_to_array(o)
case o
when NilClass
[]
when Array
o
else
[o]
end
end
def array_of_strings?(o)
o.is_a?(Array) && o.all?{|obj| obj.is_a?(String)}
end
def add_order!(sql, order, scope = :auto)
scope = scope(:find) if :auto == scope
scoped_order = scope[:order] if scope
if order
sql << " ORDER BY #{order}"
if scoped_order && scoped_order != order
sql << ", #{scoped_order}"
end
else
sql << " ORDER BY #{scoped_order}" if scoped_order
end
end
def add_group!(sql, group, having, scope = :auto)
if group
sql << " GROUP BY #{group}"
sql << " HAVING #{sanitize_sql_for_conditions(having)}" if having
else
scope = scope(:find) if :auto == scope
if scope && (scoped_group = scope[:group])
sql << " GROUP BY #{scoped_group}"
sql << " HAVING #{sanitize_sql_for_conditions(scope[:having])}" if scope[:having]
end
end
end
# The optional scope argument is for the current <tt>:find</tt> scope.
def add_limit!(sql, options, scope = :auto)
scope = scope(:find) if :auto == scope
if scope
options[:limit] ||= scope[:limit]
options[:offset] ||= scope[:offset]
end
connection.add_limit_offset!(sql, options)
end
# The optional scope argument is for the current <tt>:find</tt> scope.
# The <tt>:lock</tt> option has precedence over a scoped <tt>:lock</tt>.
def add_lock!(sql, options, scope = :auto)
scope = scope(:find) if :auto == scope
options = options.reverse_merge(:lock => scope[:lock]) if scope
connection.add_lock!(sql, options)
end
# The optional scope argument is for the current <tt>:find</tt> scope.
def add_joins!(sql, joins, scope = :auto)
scope = scope(:find) if :auto == scope
merged_joins = scope && scope[:joins] && joins ? merge_joins(scope[:joins], joins) : (joins || scope && scope[:joins])
case merged_joins
when Symbol, Hash, Array
if array_of_strings?(merged_joins)
sql << merged_joins.join(' ') + " "
else
join_dependency = ActiveRecord::Associations::ClassMethods::InnerJoinDependency.new(self, merged_joins, nil)
sql << " #{join_dependency.join_associations.collect { |assoc| assoc.association_join }.join} "
end
when String
sql << " #{merged_joins} "
end
end
# Adds a sanitized version of +conditions+ to the +sql+ string. Note that the passed-in +sql+ string is changed.
# The optional scope argument is for the current <tt>:find</tt> scope.
def add_conditions!(sql, conditions, scope = :auto)
scope = scope(:find) if :auto == scope
conditions = [conditions]
conditions << scope[:conditions] if scope
conditions << type_condition if finder_needs_type_condition?
merged_conditions = merge_conditions(*conditions)
sql << "WHERE #{merged_conditions} " unless merged_conditions.blank?
end
def type_condition(table_alias=nil)
quoted_table_alias = self.connection.quote_table_name(table_alias || table_name)
quoted_inheritance_column = connection.quote_column_name(inheritance_column)
type_condition = subclasses.inject("#{quoted_table_alias}.#{quoted_inheritance_column} = '#{sti_name}' ") do |condition, subclass|
condition << "OR #{quoted_table_alias}.#{quoted_inheritance_column} = '#{subclass.sti_name}' "
end
" (#{type_condition}) "
end
# Guesses the table name, but does not decorate it with prefix and suffix information.
def undecorated_table_name(class_name = base_class.name)
table_name = class_name.to_s.demodulize.underscore
table_name = table_name.pluralize if pluralize_table_names
table_name
end
# Enables dynamic finders like <tt>find_by_user_name(user_name)</tt> and <tt>find_by_user_name_and_password(user_name, password)</tt>
# that are turned into <tt>find(:first, :conditions => ["user_name = ?", user_name])</tt> and
# <tt>find(:first, :conditions => ["user_name = ? AND password = ?", user_name, password])</tt> respectively. Also works for
# <tt>find(:all)</tt> by using <tt>find_all_by_amount(50)</tt> that is turned into <tt>find(:all, :conditions => ["amount = ?", 50])</tt>.
#
# It's even possible to use all the additional parameters to +find+. For example, the full interface for +find_all_by_amount+
# is actually <tt>find_all_by_amount(amount, options)</tt>.
#
# Also enables dynamic scopes like scoped_by_user_name(user_name) and scoped_by_user_name_and_password(user_name, password) that
# are turned into scoped(:conditions => ["user_name = ?", user_name]) and scoped(:conditions => ["user_name = ? AND password = ?", user_name, password])
# respectively.
#
# Each dynamic finder, scope or initializer/creator is also defined in the class after it is first invoked, so that future
# attempts to use it do not run through method_missing.
def method_missing(method_id, *arguments, &block)
if match = DynamicFinderMatch.match(method_id)
attribute_names = match.attribute_names
super unless all_attributes_exists?(attribute_names)
if match.finder?
finder = match.finder
bang = match.bang?
# def self.find_by_login_and_activated(*args)
# options = args.extract_options!
# attributes = construct_attributes_from_arguments(
# [:login,:activated],
# args
# )
# finder_options = { :conditions => attributes }
# validate_find_options(options)
# set_readonly_option!(options)
#
# if options[:conditions]
# with_scope(:find => finder_options) do
# find(:first, options)
# end
# else
# find(:first, options.merge(finder_options))
# end
# end
self.class_eval %{
def self.#{method_id}(*args)
options = args.extract_options!
attributes = construct_attributes_from_arguments(
[:#{attribute_names.join(',:')}],
args
)
finder_options = { :conditions => attributes }
validate_find_options(options)
set_readonly_option!(options)
#{'result = ' if bang}if options[:conditions]
with_scope(:find => finder_options) do
find(:#{finder}, options)
end
else
find(:#{finder}, options.merge(finder_options))
end
#{'result || raise(RecordNotFound, "Couldn\'t find #{name} with #{attributes.to_a.collect { |pair| pair.join(\' = \') }.join(\', \')}")' if bang}
end
}, __FILE__, __LINE__
send(method_id, *arguments)
elsif match.instantiator?
instantiator = match.instantiator
# def self.find_or_create_by_user_id(*args)
# guard_protected_attributes = false
#
# if args[0].is_a?(Hash)
# guard_protected_attributes = true
# attributes = args[0].with_indifferent_access
# find_attributes = attributes.slice(*[:user_id])
# else
# find_attributes = attributes = construct_attributes_from_arguments([:user_id], args)
# end
#
# options = { :conditions => find_attributes }
# set_readonly_option!(options)
#
# record = find(:first, options)
#
# if record.nil?
# record = self.new { |r| r.send(:attributes=, attributes, guard_protected_attributes) }
# yield(record) if block_given?
# record.save
# record
# else
# record
# end
# end
self.class_eval %{
def self.#{method_id}(*args)
guard_protected_attributes = false
if args[0].is_a?(Hash)
guard_protected_attributes = true
attributes = args[0].with_indifferent_access
find_attributes = attributes.slice(*[:#{attribute_names.join(',:')}])
else
find_attributes = attributes = construct_attributes_from_arguments([:#{attribute_names.join(',:')}], args)
end
options = { :conditions => find_attributes }
set_readonly_option!(options)
record = find(:first, options)
if record.nil?
record = self.new { |r| r.send(:attributes=, attributes, guard_protected_attributes) }
#{'yield(record) if block_given?'}
#{'record.save' if instantiator == :create}
record
else
record
end
end
}, __FILE__, __LINE__
send(method_id, *arguments, &block)
end
elsif match = DynamicScopeMatch.match(method_id)
attribute_names = match.attribute_names
super unless all_attributes_exists?(attribute_names)
if match.scope?
self.class_eval %{
def self.#{method_id}(*args) # def self.scoped_by_user_name_and_password(*args)
options = args.extract_options! # options = args.extract_options!
attributes = construct_attributes_from_arguments( # attributes = construct_attributes_from_arguments(
[:#{attribute_names.join(',:')}], args # [:user_name, :password], args
) # )
#
scoped(:conditions => attributes) # scoped(:conditions => attributes)
end # end
}, __FILE__, __LINE__
send(method_id, *arguments)
end
else
super
end
end
def construct_attributes_from_arguments(attribute_names, arguments)
attributes = {}
attribute_names.each_with_index { |name, idx| attributes[name] = arguments[idx] }
attributes
end
# Similar in purpose to +expand_hash_conditions_for_aggregates+.
def expand_attribute_names_for_aggregates(attribute_names)
expanded_attribute_names = []
attribute_names.each do |attribute_name|
unless (aggregation = reflect_on_aggregation(attribute_name.to_sym)).nil?
aggregate_mapping(aggregation).each do |field_attr, aggregate_attr|
expanded_attribute_names << field_attr
end
else
expanded_attribute_names << attribute_name
end
end
expanded_attribute_names
end
def all_attributes_exists?(attribute_names)
attribute_names = expand_attribute_names_for_aggregates(attribute_names)
attribute_names.all? { |name| column_methods_hash.include?(name.to_sym) }
end
def attribute_condition(quoted_column_name, argument)
case argument
when nil then "#{quoted_column_name} IS ?"
when Array, ActiveRecord::Associations::AssociationCollection, ActiveRecord::NamedScope::Scope then "#{quoted_column_name} IN (?)"
when Range then if argument.exclude_end?
"#{quoted_column_name} >= ? AND #{quoted_column_name} < ?"
else
"#{quoted_column_name} BETWEEN ? AND ?"
end
else "#{quoted_column_name} = ?"
end
end
# Interpret Array and Hash as conditions and anything else as an id.
def expand_id_conditions(id_or_conditions)
case id_or_conditions
when Array, Hash then id_or_conditions
else sanitize_sql(primary_key => id_or_conditions)
end
end
# Defines an "attribute" method (like +inheritance_column+ or
# +table_name+). A new (class) method will be created with the
# given name. If a value is specified, the new method will
# return that value (as a string). Otherwise, the given block
# will be used to compute the value of the method.
#
# The original method will be aliased, with the new name being
# prefixed with "original_". This allows the new method to
# access the original value.
#
# Example:
#
# class A < ActiveRecord::Base
# define_attr_method :primary_key, "sysid"
# define_attr_method( :inheritance_column ) do
# original_inheritance_column + "_id"
# end
# end
def define_attr_method(name, value=nil, &block)
sing = metaclass
sing.send :alias_method, "original_#{name}", name
if block_given?
sing.send :define_method, name, &block
else
# use eval instead of a block to work around a memory leak in dev
# mode in fcgi
sing.class_eval "def #{name}; #{value.to_s.inspect}; end"
end
end
protected
# Scope parameters to method calls within the block. Takes a hash of method_name => parameters hash.
# method_name may be <tt>:find</tt> or <tt>:create</tt>. <tt>:find</tt> parameters may include the <tt>:conditions</tt>, <tt>:joins</tt>,
# <tt>:include</tt>, <tt>:offset</tt>, <tt>:limit</tt>, and <tt>:readonly</tt> options. <tt>:create</tt> parameters are an attributes hash.
#
# class Article < ActiveRecord::Base
# def self.create_with_scope
# with_scope(:find => { :conditions => "blog_id = 1" }, :create => { :blog_id => 1 }) do
# find(1) # => SELECT * from articles WHERE blog_id = 1 AND id = 1
# a = create(1)
# a.blog_id # => 1
# end
# end
# end
#
# In nested scopings, all previous parameters are overwritten by the innermost rule, with the exception of
# <tt>:conditions</tt>, <tt>:include</tt>, and <tt>:joins</tt> options in <tt>:find</tt>, which are merged.
#
# <tt>:joins</tt> options are uniqued so multiple scopes can join in the same table without table aliasing
# problems. If you need to join multiple tables, but still want one of the tables to be uniqued, use the
# array of strings format for your joins.
#
# class Article < ActiveRecord::Base
# def self.find_with_scope
# with_scope(:find => { :conditions => "blog_id = 1", :limit => 1 }, :create => { :blog_id => 1 }) do
# with_scope(:find => { :limit => 10 })
# find(:all) # => SELECT * from articles WHERE blog_id = 1 LIMIT 10
# end
# with_scope(:find => { :conditions => "author_id = 3" })
# find(:all) # => SELECT * from articles WHERE blog_id = 1 AND author_id = 3 LIMIT 1
# end
# end
# end
# end
#
# You can ignore any previous scopings by using the <tt>with_exclusive_scope</tt> method.
#
# class Article < ActiveRecord::Base
# def self.find_with_exclusive_scope
# with_scope(:find => { :conditions => "blog_id = 1", :limit => 1 }) do
# with_exclusive_scope(:find => { :limit => 10 })
# find(:all) # => SELECT * from articles LIMIT 10
# end
# end
# end
# end
#
# *Note*: the +:find+ scope also has effect on update and deletion methods,
# like +update_all+ and +delete_all+.
def with_scope(method_scoping = {}, action = :merge, &block)
method_scoping = method_scoping.method_scoping if method_scoping.respond_to?(:method_scoping)
# Dup first and second level of hash (method and params).
&nbs
) is private.
