/activerecord/lib/active_record/base.rb
Ruby | 2409 lines | 1133 code | 226 blank | 1050 comment | 129 complexity | 04dcb2c88b05eaba6c3688d700b5a19e MD5 | raw file
Possible License(s): ISC
Large files files are truncated, but you can click here to view the full file
- 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/singleton_class'
- 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
- 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_…
Large files files are truncated, but you can click here to view the full file