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base.rb
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base.rb
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require 'yaml'
require 'set'
require 'active_support/benchmarkable'
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/object/metaclass'
require 'active_support/core_ext/module/delegation'
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
# Raised when SQL statement is invalid and the application gets a blank result.
class ThrowResult < 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 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] })
#
# When joining tables, nested hashes or keys written in the form 'table_name.column_name' can be used to qualify the table name of a
# particular condition. For instance:
#
# Student.find(:all, :conditions => { :schools => { :type => 'public' }}, :joins => :schools)
# Student.find(:all, :conditions => { 'schools.type' => 'public' }, :joins => :schools)
#
# == 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 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 = true
# Stores the default scope for the class
class_inheritable_accessor :default_scoping, :instance_writer => false
self.default_scoping = []
class << self # Class methods
def colorize_logging(*args)
ActiveSupport::Deprecation.warn "ActiveRecord::Base.colorize_logging and " <<
"config.active_record.colorize_logging are deprecated. Please use " <<
"Rails::LogSubscriber.colorize_logging or config.colorize_logging instead", caller
end
alias :colorize_logging= :colorize_logging
delegate :find, :first, :last, :all, :destroy, :destroy_all, :exists?, :delete, :delete_all, :update, :update_all, :to => :scoped
delegate :find_each, :find_in_batches, :to => :scoped
delegate :select, :group, :order, :limit, :joins, :where, :preload, :eager_load, :includes, :from, :lock, :readonly, :having, :to => :scoped
delegate :count, :average, :minimum, :maximum, :sum, :calculate, :to => :scoped
# 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
# 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
# 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
# Resets one or more counter caches to their correct value using an SQL
# count query. This is useful when adding new counter caches, or if the
# counter has been corrupted or modified directly by SQL.
#
# ==== Parameters
#
# * +id+ - The id of the object you wish to reset a counter on.
# * +counters+ - One or more counter names to reset
#
# ==== Examples
#
# # For Post with id #1 records reset the comments_count
# Post.reset_counters(1, :comments)
def reset_counters(id, *counters)
object = find(id)
counters.each do |association|
child_class = reflect_on_association(association).klass
counter_name = child_class.reflect_on_association(self.name.downcase.to_sym).counter_cache_column
connection.update("UPDATE #{quoted_table_name} SET #{connection.quote_column_name(counter_name)} = #{object.send(association).count} WHERE #{connection.quote_column_name(primary_key)} = #{quote_value(object.id)}", "#{name} UPDATE")
end
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+.
#
# If the access logic of your application is richer you can use <tt>Hash#except</tt>
# or <tt>Hash#slice</tt> to sanitize the hash of parameters before they are
# passed to Active Record.
#
# For example, it could be the case that the list of protected attributes
# for a given model depends on the role of the user:
#
# # Assumes plan_id is not protected because it depends on the role.
# params[:account] = params[:account].except(:plan_id) unless admin?
# @account.update_attributes(params[:account])
#
# Note that +attr_protected+ is still applied to the received hash. Thus,
# with this technique you can at most _extend_ the list of protected
# attributes for a particular mass-assignment call.
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"
#
# If the access logic of your application is richer you can use <tt>Hash#except</tt>
# or <tt>Hash#slice</tt> to sanitize the hash of parameters before they are
# passed to Active Record.
#
# For example, it could be the case that the list of accessible attributes
# for a given model depends on the role of the user:
#
# # Assumes plan_id is accessible because it depends on the role.
# params[:account] = params[:account].except(:plan_id) unless admin?
# @account.update_attributes(params[:account])
#
# Note that +attr_accessible+ is still applied to the received hash. Thus,
# with this technique you can at most _narrow_ the list of accessible
# attributes for a particular mass-assignment call.
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 quoted_table_name
@quoted_table_name ||= connection.quote_table_name(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
@quoted_table_name = nil
set_table_name(name)
name
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 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