ActiveRecord::Base (original) (raw)

Active Record

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 files/activerecord/README_rdoc.htmlfor 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

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) where("user_name = '#{user_name}' AND password = '#{password}'").first end

def self.authenticate_safely(user_name, password) where("user_name = ? AND password = ?", user_name, password).first end

def self.authenticate_safely_simply(user_name, password) where(:user_name => user_name, :password => password).first end end

The authenticate_unsafely method inserts the parameters directly into the query and is thus susceptible to SQL-injection attacks if the user_name and password parameters come directly from an HTTP request. The authenticate_safely andauthenticate_safely_simply both will sanitize theuser_name 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.where( "id = :id AND name = :name AND division = :division AND created_at > :accounting_date", { :id => 3, :name => "37signals", :division => "First", :accounting_date => '2005-01-01' } ).first

Similarly, a simple hash without a statement will generate conditions based on equality with the SQL AND operator. For instance:

Student.where(:first_name => "Harvey", :status => 1) Student.where(params[:student])

A range may be used in the hash to use the SQL BETWEEN operator:

Student.where(:grade => 9..12)

An array may be used in the hash to use the SQL IN operator:

Student.where(: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.joins(:schools).where(:schools => { :category => 'public' }) Student.joins(:schools).where('schools.category' => 'public' )

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 callingread_attribute(attr_name) and write_attribute(attr_name, value) to actually change things.

class Song < ActiveRecord::Base

def length=(minutes) write_attribute(:length, minutes.to_i * 60) end

def length read_attribute(:length) / 60 end end

You can alternatively use self[:attribute]=(value) andself[:attribute] instead of write_attribute(:attribute, value) and read_attribute(:attribute).

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 name attribute has a name? method that you can call to determine whether the user has a name:

user = User.new(:name => "David") user.name?

anonymous = User.new(:name => "") anonymous.name?

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 <attribute>_before_type_cast accessors that all attributes have. For example, if your Account model has abalance attribute, you can callaccount.balance_before_type_cast oraccount.id_before_type_cast.

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 find_by_,find_last_by_, or find_all_by_ and thus produces finders like Person.find_by_user_name,Person.find_all_by_last_name, andPayment.find_by_transaction_id. Instead of writingPerson.where(:user_name => user_name).first, you just doPerson.find_by_user_name(user_name). And instead of writingPerson.where(:last_name => last_name).all, you just doPerson.find_all_by_last_name(last_name).

It’s also possible to use multiple attributes in the same find by separating them with “_and_”.

Person.where(:user_name => user_name, :password => password).first Person.find_by_user_name_and_password(user_name, password)

It’s even possible to call these dynamic finder methods on relations and named scopes.

Payment.order("created_on").find_all_by_amount(50) Payment.pending.find_last_by_amount(100)

The same dynamic finder style can be used to create the object if it doesn’t already exist. This dynamic finder is called withfind_or_create_by_ 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.

Tag.find_or_create_by_name("Summer")

Tag.find_or_create_by_name("Summer")

User.find_or_create_by_name('Bob', :age => 40) { |u| u.admin = true }

Use the find_or_initialize_by_ 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.

No 'Winter' tag exists

winter = Tag.find_or_initialize_by_name("Winter") winter.persisted? # false

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.

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.

Just like find_by_*, you can also use scoped_by_*to retrieve data. The good thing about using this feature is that the very first time result is returned using method_missing technique but after that the method is declared on the class. Henceforthmethod_missing will not be hit.

User.scoped_by_user_name('David')

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 methodserialize. This makes it possible to store arrays, hashes, and other non-mappable objects without doing any additional work.

class User < ActiveRecord::Base serialize :preferences end

user = User.create(:preferences => { "background" => "black", "display" => large }) User.find(user.id).preferences

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.

class User < ActiveRecord::Base serialize :preferences, Hash end

user = User.create(:preferences => %W( one two three )) User.find(user.id).preferences

When you specify a class option, the default value for that attribute will be a new instance of that class.

class User < ActiveRecord::Base serialize :preferences, OpenStruct end

user = User.new user.preferences.theme_color = "red"

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 overwritingBase.inheritance_column). 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 Firm.create(:name => "37signals"), this record will be saved in the companies table with type = “Firm”. You can then fetch this row again using Company.where(:name => '37signals').first 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: www.martinfowler.com/eaaCatalog/singleTableInheritance.html

Connection to multiple databases in different models

Connections are usually created through ::establish_connectionand retrieved by #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 sayCourse.establish_connection 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_connectionmethod will go up the class-hierarchy until a connection is found in the connection pool.

Exceptions

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 Base.logger= which will then be used by all instances in the current object space.

Methods

A

B

C

D

E

F

H

I

L

M

N

P

Q

R

S

T

W

Attributes

[RW] abstract_class Set this to true if this is an abstract class (seeabstract_class?).

Class Public methods

===(object)

Overwrite the default class equality method to provide support for association proxies.

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def ===(object) object.is_a?(self) end

abstract_class?()

Returns whether this class is an abstract class or not.

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def abstract_class? defined?(@abstract_class) && @abstract_class == true end

arel_engine()

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def arel_engine @arel_engine ||= begin if self == ActiveRecord::Base ActiveRecord::Base else connection_handler.connection_pools[name] ? self : superclass.arel_engine end end end

arel_table()

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def arel_table @arel_table ||= Arel::Table.new(table_name, arel_engine) end

attr_readonly(*attributes)

Attributes listed as readonly will be used to create a new record but update operations will ignore these fields.

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def attr_readonly(*attributes) self._attr_readonly = Set.new(attributes.map { |a| a.to_s }) + (self._attr_readonly || []) end

attribute_method?(attribute)

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def attribute_method?(attribute) super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, ''))) end

attribute_names()

Returns an array of column names as strings if it’s not an abstract class and table exists. Otherwise it returns an empty array.

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def attribute_names @attribute_names ||= if !abstract_class? && table_exists? column_names else [] end end

base_class()

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.

If B < A and C < B and if A is an ::abstract_class then both B.base_class and C.base_class would return B as the answer since A is an abstract_class.

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def base_class class_of_active_record_descendant(self) end

clear_active_connections!()

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def clear_active_connections! connection_handler.clear_active_connections! end

column_defaults()

Returns a hash where the keys are column names and the values are default values when instantiating the AR object for this table.

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def column_defaults connection_pool.column_defaults[table_name] end

column_names()

Returns an array of column names as strings.

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def column_names @column_names ||= columns.map { |column| column.name } end

columns()

Returns an array of column objects for the table associated with this class.

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def columns if defined?(@primary_key) connection_pool.primary_keys[table_name] ||= primary_key end

connection_pool.columns[table_name] end

columns_hash()

Returns a hash of column objects for the table associated with this class.

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def columns_hash connection_pool.columns_hash[table_name] end

configurations

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 ::configurations to look like this:

{ 'development' => { 'adapter' => 'sqlite3', 'database' => 'db/development.sqlite3' }, 'production' => { 'adapter' => 'sqlite3', 'database' => 'db/production.sqlite3' } }

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cattr_accessor :configurations, :instance_writer => false

connected?()

Returns true if Active Record is connected.

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def connected? connection_handler.connected?(self) end

connection()

Returns the connection currently associated with the class. This can also be used to “borrow” the connection to do database work unrelated to any of the specific Active Records.

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def connection retrieve_connection end

connection_config()

Returns the configuration of the associated connection as a hash:

ActiveRecord::Base.connection_config

Please use only for reading.

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def connection_config connection_pool.spec.config end

connection_handler

The connection handler

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class_attribute :connection_handler, :instance_writer => false

connection_id()

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def connection_id Thread.current['ActiveRecord::Base.connection_id'] end

connection_id=(connection_id)

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def connection_id=(connection_id) Thread.current['ActiveRecord::Base.connection_id'] = connection_id end

connection_pool()

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def connection_pool connection_handler.retrieve_connection_pool(self) or raise ConnectionNotEstablished end

content_columns()

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.

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def content_columns @content_columns ||= columns.reject { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column } end

count_by_sql(sql)

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

Examples

Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"

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def count_by_sql(sql) sql = sanitize_conditions(sql) connection.select_value(sql, "#{name} Count").to_i end

create(attributes = nil, options = {}, &block)

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.

create respects mass-assignment security and accepts either:as or :without_protection options in theoptions parameter.

Examples

User.create(:first_name => 'Jamie')

User.create({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)

User.create({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)

User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }])

User.create(:first_name => 'Jamie') do |u| u.is_admin = false end

User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }]) do |u| u.is_admin = false end

Source: show

def create(attributes = nil, options = {}, &block) if attributes.is_a?(Array) attributes.collect { |attr| create(attr, options, &block) } else object = new(attributes, options) yield(object) if block_given? object.save object end end

default_timezone

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.

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cattr_accessor :default_timezone, :instance_writer => false

descends_from_active_record?()

True if this isn’t a concrete subclass needing a STI type condition.

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def descends_from_active_record? if superclass.abstract_class? superclass.descends_from_active_record? else superclass == Base || !columns_hash.include?(inheritance_column) end end

establish_connection(spec = nil)

Establishes the connection to the database. Accepts a hash as input where the :adapter key must be specified with the name of a database adapter (in lower-case) example for regular databases (MySQL, Postgresql, etc):

ActiveRecord::Base.establish_connection( :adapter => "mysql", :host => "localhost", :username => "myuser", :password => "mypass", :database => "somedatabase" )

Example for SQLite database:

ActiveRecord::Base.establish_connection( :adapter => "sqlite", :database => "path/to/dbfile" )

Also accepts keys as strings (for parsing from YAML for example):

ActiveRecord::Base.establish_connection( "adapter" => "sqlite", "database" => "path/to/dbfile" )

The exceptions AdapterNotSpecified,AdapterNotFound and ArgumentError may be returned on an error.

Source: show

def self.establish_connection(spec = nil) case spec when nil raise AdapterNotSpecified unless defined?(Rails.env) establish_connection(Rails.env) when ConnectionSpecification self.connection_handler.establish_connection(name, spec) when Symbol, String if configuration = configurations[spec.to_s] establish_connection(configuration) else raise AdapterNotSpecified, "#{spec} database is not configured" end else spec = spec.symbolize_keys unless spec.key?(:adapter) then raise AdapterNotSpecified, "database configuration does not specify adapter" end

  begin
    require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
  rescue LoadError => e
    raise "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{e})"
  end

  adapter_method = "#{spec[:adapter]}_connection"
  unless respond_to?(adapter_method)
    raise AdapterNotFound, "database configuration specifies nonexistent #{spec[:adapter]} adapter"
  end

  remove_connection
  establish_connection(ConnectionSpecification.new(spec, adapter_method))

end end

find_by_sql(sql, binds = [])

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 Product.find_by_sql 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

Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id"

[

Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date]

[

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def find_by_sql(sql, binds = []) connection.select_all(sanitize_sql(sql), "#{name} Load", binds).collect! { |record| instantiate(record) } end

inheritance_column()

Defines the column name for use with single table inheritance. Useset_inheritance_column to set a different value.

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def inheritance_column @inheritance_column ||= "type" end

inheritance_column=(value = nil, &block)

inspect()

Returns a string like ‘Post(id:integer, title:string, body:text)’

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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

instantiate(record)

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.

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def instantiate(record) sti_class = find_sti_class(record[inheritance_column]) record_id = sti_class.primary_key && record[sti_class.primary_key]

if ActiveRecord::IdentityMap.enabled? && record_id if (column = sti_class.columns_hash[sti_class.primary_key]) && column.number? record_id = record_id.to_i end if instance = IdentityMap.get(sti_class, record_id) instance.reinit_with('attributes' => record) else instance = sti_class.allocate.init_with('attributes' => record) IdentityMap.add(instance) end else instance = sti_class.allocate.init_with('attributes' => record) end

instance end

logger

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.

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cattr_accessor :logger, :instance_writer => false

mysql2_connection(config)

Establishes a connection to the database that’s used by all Active Record objects.

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def self.mysql2_connection(config) config[:username] = 'root' if config[:username].nil?

if Mysql2::Client.const_defined? :FOUND_ROWS config[:flags] = Mysql2::Client::FOUND_ROWS end

client = Mysql2::Client.new(config.symbolize_keys) options = [config[:host], config[:username], config[:password], config[:database], config[:port], config[:socket], 0] ConnectionAdapters::Mysql2Adapter.new(client, logger, options, config) end

new(attributes = nil, options = {})

New objects can be instantiated as either empty (pass no construction parameter) or pre-set with attributes but not yet saved (pass a hash with key names matching the associated table column names). In both instances, valid attribute keys are determined by the column names of the associated table – hence you can’t have attributes that aren’t part of the table columns.

initialize respects mass-assignment security and accepts either :as or :without_protection options in theoptions parameter.

Examples

User.new(:first_name => 'Jamie')

User.new({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)

User.new({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)

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def initialize(attributes = nil, options = {}) @attributes = attributes_from_column_definition @association_cache = {} @aggregation_cache = {} @attributes_cache = {} @new_record = true @readonly = false @destroyed = false @marked_for_destruction = false @previously_changed = {} @changed_attributes = {} @relation = nil

ensure_proper_type set_serialized_attributes

populate_with_current_scope_attributes

assign_attributes(attributes, options) if attributes

yield self if block_given? run_callbacks :initialize end

pluralize_table_names

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 beproduct. See ::table_name for the full rules on table/class naming. This is true, by default.

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class_attribute :pluralize_table_names, :instance_writer => false

primary_key_prefix_type

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.

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cattr_accessor :primary_key_prefix_type, :instance_writer => false

quoted_table_name()

Returns a quoted version of the table name, used to construct SQL statements.

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def quoted_table_name @quoted_table_name ||= connection.quote_table_name(table_name) end

readonly_attributes()

Returns an array of all the attributes that have been specified as readonly.

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def readonly_attributes self._attr_readonly end

remove_connection(klass = self)

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def remove_connection(klass = self) connection_handler.remove_connection(klass) end

reset_column_information()

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 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 down drop_table :job_levels end end

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def reset_column_information connection.clear_cache! undefine_attribute_methods connection_pool.clear_table_cache!(table_name) if table_exists?

@column_names = @content_columns = @dynamic_methods_hash = @inheritance_column = nil @arel_engine = @relation = nil end

respond_to?(method_id, include_private = false)

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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

retrieve_connection()

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def retrieve_connection connection_handler.retrieve_connection(self) end

schema_format

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.

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cattr_accessor :schema_format , :instance_writer => false

sequence_name=(value = nil, &block)

serialize(attr_name, class_name = Object)

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

Example

class User < ActiveRecord::Base serialize :preferences end

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def serialize(attr_name, class_name = Object) coder = if [:load, :dump].all? { |x| class_name.respond_to?(x) } class_name else Coders::YAMLColumn.new(class_name) end

self.serialized_attributes = serialized_attributes.merge(attr_name.to_s => coder) end

set_inheritance_column(value = nil, &block)

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

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def set_inheritance_column(value = nil, &block) define_attr_method :inheritance_column, value, &block end

set_sequence_name(value = nil, &block)

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"
end

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def set_sequence_name(value = nil, &block) define_attr_method :sequence_name, value, &block end

set_table_name(value = nil, &block)

Sets the table name. If the value is nil or false then the value returned by the given block is used.

class Project < ActiveRecord::Base set_table_name "project" end

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def set_table_name(value = nil, &block) @quoted_table_name = nil define_attr_method :table_name, value, &block @arel_table = nil

@arel_table = Arel::Table.new(table_name, arel_engine) @relation = Relation.new(self, arel_table) end

sti_name()

Source: show

def sti_name store_full_sti_class ? name : name.demodulize end

symbolized_base_class()

Source: show

def symbolized_base_class @symbolized_base_class ||= base_class.to_s.to_sym end

symbolized_sti_name()

Source: show

def symbolized_sti_name @symbolized_sti_name ||= sti_name.present? ? sti_name.to_sym : symbolized_base_class end

table_exists?()

Indicates whether the table associated with this class exists

Source: show

def table_exists? connection.table_exists?(table_name) end

table_name()

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

Source: show

def table_name reset_table_name end

table_name=(value = nil, &block)

table_name_prefix

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.

If you are organising your models within modules you can add a prefix to the models within a namespace by defining a singleton method in the parent module called ::table_name_prefix which returns your chosen prefix.

Source: show

class_attribute :table_name_prefix, :instance_writer => false

table_name_suffix

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.

Source: show

class_attribute :table_name_suffix, :instance_writer => false

timestamped_migrations

Specify whether or not to use timestamps for migration versions

Source: show

cattr_accessor :timestamped_migrations , :instance_writer => false

Class Protected methods

aggregate_mapping(reflection)

Source: show

def aggregate_mapping(reflection) mapping = reflection.options[:mapping] || [reflection.name, reflection.name] mapping.first.is_a?(Array) ? mapping : [mapping] end

class_of_active_record_descendant(klass)

Returns the class descending directly from ActiveRecord::Base or an abstract class, if any, in the inheritance hierarchy.

Source: show

def class_of_active_record_descendant(klass) if klass.superclass == Base || klass.superclass.abstract_class? klass elsif klass.superclass.nil? raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord" else class_of_active_record_descendant(klass.superclass) end end

compute_type(type_name)

Returns the class type of the record using the current module as a prefix. So descendants of MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.

Source: show

def compute_type(type_name) if type_name.match(/^::/)

ActiveSupport::Dependencies.constantize(type_name)

else

candidates = []
name.scan(/::|$/) { candidates.unshift "#{$`}::#{type_name}" }
candidates << type_name

candidates.each do |candidate|
  begin
    constant = ActiveSupport::Dependencies.constantize(candidate)
    return constant if candidate == constant.to_s
  rescue NameError => e
    
    raise e unless e.instance_of?(NameError)
  end
end

raise NameError, "uninitialized constant #{candidates.first}"

end end

default_scope(scope = {})

Use this macro in your model to set a default scope for all operations on the model.

class Article < ActiveRecord::Base default_scope where(:published => true) end

Article.all

The default_scope is also applied while creating/building a record. It is not applied while updating a record.

Article.new.published
Article.create.published

You can also use default_scope with a block, in order to have it lazily evaluated:

class Article < ActiveRecord::Base default_scope { where(:published_at => Time.now - 1.week) } end

(You can also pass any object which responds to call to thedefault_scope macro, and it will be called when building the default scope.)

If you use multiple default_scope declarations in your model then they will be merged together:

class Article < ActiveRecord::Base default_scope where(:published => true) default_scope where(:rating => 'G') end

Article.all

This is also the case with inheritance and module includes where the parent or module defines a default_scope and the child or including class defines a second one.

If you need to do more complex things with a default scope, you can alternatively define it as a class method:

class Article < ActiveRecord::Base def self.default_scope

end end

Source: show

def default_scope(scope = {}) scope = Proc.new if block_given? self.default_scopes = default_scopes + [scope] end

evaluate_default_scope()

The ignore_default_scope flag is used to prevent an infinite recursion situation where a default scope references a scope which has a default scope which references a scope…

Source: show

def evaluate_default_scope return if ignore_default_scope?

begin self.ignore_default_scope = true yield ensure self.ignore_default_scope = false end end

expand_hash_conditions_for_aggregates(attrs)

Accepts a hash of SQL conditions and replaces those attributes that correspond to a composed_of relationship with their expanded aggregate attribute values. Given:

class Person < ActiveRecord::Base composed_of :address, :class_name => "Address", :mapping => [%W(address_street street), %W(address_city city)] end

Then:

{ :address => Address.new("813 abc st.", "chicago") }

Source: show

def expand_hash_conditions_for_aggregates(attrs) expanded_attrs = {} attrs.each do |attr, value| unless (aggregation = reflect_on_aggregation(attr.to_sym)).nil? mapping = aggregate_mapping(aggregation) mapping.each do |field_attr, aggregate_attr| if mapping.size == 1 && !value.respond_to?(aggregate_attr) expanded_attrs[field_attr] = value else expanded_attrs[field_attr] = value.send(aggregate_attr) end end else expanded_attrs[attr] = value end end expanded_attrs end

sanitize_conditions(condition, table_name = self.table_name)

sanitize_sql(condition, table_name = self.table_name)

sanitize_sql_array(ary)

Accepts an array of conditions. The array has each value sanitized and interpolated into the SQL statement.

["name='%s' and group_id='%s'", "foo'bar", 4] returns "name='foo''bar' and group_id='4'"

Source: show

def sanitize_sql_array(ary) statement, *values = ary if values.first.is_a?(Hash) && statement =~ /:\w+/ replace_named_bind_variables(statement, values.first) elsif statement.include?('?') replace_bind_variables(statement, values) elsif statement.blank? statement else statement % values.collect { |value| connection.quote_string(value.to_s) } end end

sanitize_sql_for_assignment(assignments)

Accepts an array, hash, or string of SQL conditions and sanitizes them into a valid SQL fragment for a SET clause.

{ :name => nil, :group_id => 4 } returns "name = NULL , group_id='4'"

Source: show

def sanitize_sql_for_assignment(assignments) case assignments when Array; sanitize_sql_array(assignments) when Hash; sanitize_sql_hash_for_assignment(assignments) else assignments end end

sanitize_sql_for_conditions(condition, table_name = self.table_name)

Accepts an array, hash, or string of SQL conditions and sanitizes them into a valid SQL fragment for a WHERE clause.

["name='%s' and group_id='%s'", "foo'bar", 4] returns "name='foo''bar' and group_id='4'" { :name => "foo'bar", :group_id => 4 } returns "name='foo''bar' and group_id='4'" "name='foo''bar' and group_id='4'" returns "name='foo''bar' and group_id='4'"

Source: show

def sanitize_sql_for_conditions(condition, table_name = self.table_name) return nil if condition.blank?

case condition when Array; sanitize_sql_array(condition) when Hash; sanitize_sql_hash_for_conditions(condition, table_name) else condition end end

sanitize_sql_hash(attrs, default_table_name = self.table_name)

sanitize_sql_hash_for_assignment(attrs)

Sanitizes a hash of attribute/value pairs into SQL conditions for a SET clause.

{ :status => nil, :group_id => 1 }

Source: show

def sanitize_sql_hash_for_assignment(attrs) attrs.map do |attr, value| "#{connection.quote_column_name(attr)} = #{quote_bound_value(value)}" end.join(', ') end

sanitize_sql_hash_for_conditions(attrs, default_table_name = self.table_name)

Sanitizes a hash of attribute/value pairs into SQL conditions for a WHERE clause.

{ :name => "foo'bar", :group_id => 4 }

{ :status => nil, :group_id => [1,2,3] }

{ :age => 13..18 }

{ 'other_records.id' => 7 }

{ :other_records => { :id => 7 } }

And for value objects on a composed_of relationship:

{ :address => Address.new("123 abc st.", "chicago") }

Source: show

def sanitize_sql_hash_for_conditions(attrs, default_table_name = self.table_name) attrs = expand_hash_conditions_for_aggregates(attrs)

table = Arel::Table.new(table_name).alias(default_table_name) PredicateBuilder.build_from_hash(arel_engine, attrs, table).map { |b| connection.visitor.accept b }.join(' AND ') end

with_exclusive_scope(method_scoping = {}, &block)

Works like ::with_scope, but discards any nested properties.

Source: show 

    def with_exclusive_scope(method_scoping = {}, &block)
      if method_scoping.values.any? { |e| e.is_a?(ActiveRecord::Relation) }
        raise ArgumentError, "New finder API can not be used with_exclusive_scope. You can either call unscoped to get an anonymous scope not bound to the default_scope:

User.unscoped.where(:active => true)

Or call unscoped with a block:

User.unscoped do User.where(:active => true).all end

" end with_scope(method_scoping, :overwrite, &block) end

with_scope(scope = {}, action = :merge, &block)

::with_scope lets you apply options to inner block incrementally. It takes a hash and the keys must be:find or :create. :find parameter isRelation while :create parameters are an attributes hash.

class Article < ActiveRecord::Base def self.create_with_scope with_scope(:find => where(:blog_id => 1), :create => { :blog_id => 1 }) do find(1) a = create(1) a.blog_id end end end

In nested scopings, all previous parameters are overwritten by the innermost rule, with the exception of where,includes, and joins operations inRelation, which are merged.

joins operations 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 => where(:blog_id => 1).limit(1), :create => { :blog_id => 1 }) do with_scope(:find => limit(10)) do all end with_scope(:find => where(:author_id => 3)) do all end end end end

You can ignore any previous scopings by using thewith_exclusive_scope method.

class Article < ActiveRecord::Base def self.find_with_exclusive_scope with_scope(:find => where(:blog_id => 1).limit(1)) do with_exclusive_scope(:find => limit(10)) do all end end end end

Note: the :find scope also has effect on update and deletion methods, like update_all anddelete_all.

Source: show

def with_scope(scope = {}, action = :merge, &block)

scope = scope.current_scope if !scope.is_a?(Relation) && scope.respond_to?(:current_scope)

previous_scope = self.current_scope

if scope.is_a?(Hash)

scope = scope.dup
scope.each do |method, params|
  scope[method] = params.dup unless params == true
end

scope.assert_valid_keys([ :find, :create ])
relation = construct_finder_arel(scope[:find] || {})
relation.default_scoped = true unless action == :overwrite

if previous_scope && previous_scope.create_with_value && scope[:create]
  scope_for_create = if action == :merge
    previous_scope.create_with_value.merge(scope[:create])
  else
    scope[:create]
  end

  relation = relation.create_with(scope_for_create)
else
  scope_for_create = scope[:create]
  scope_for_create ||= previous_scope.create_with_value if previous_scope
  relation = relation.create_with(scope_for_create) if scope_for_create
end

scope = relation

end

scope = previous_scope.merge(scope) if previous_scope && action == :merge

self.current_scope = scope begin yield ensure self.current_scope = previous_scope end end

Instance Public methods

<=>(other_object)

Allows sort on objects

Source: show

def <=>(other_object) if other_object.is_a?(self.class) self.to_key <=> other_object.to_key else nil end end

==(comparison_object)

Returns true if comparison_object is the same exact object, orcomparison_object is of the same type and selfhas an ID and it is equal to comparison_object.id.

Note that new records are different from any other record by definition, unless the other record is the receiver itself. Besides, if you fetch existing records with select and leave the ID out, you’re on your own, this predicate will return false.

Note also that destroying a record preserves its ID in the model instance, so deleted models are still comparable.

Also aliased as: eql?

Source: show

def ==(comparison_object) super || comparison_object.instance_of?(self.class) && id.present? && comparison_object.id == id end

assign_attributes(new_attributes, options = {})

Allows you to set all the attributes for a particular mass-assignment security role by passing in a hash of attributes with keys matching the attribute names (which again matches the column names) and the role name using the :as option.

To bypass mass-assignment security you can use the :without_protection => true option.

class User < ActiveRecord::Base attr_accessible :name attr_accessible :name, :is_admin, :as => :admin end

user = User.new user.assign_attributes({ :name => 'Josh', :is_admin => true }) user.name
user.is_admin?

user = User.new user.assign_attributes({ :name => 'Josh', :is_admin => true }, :as => :admin) user.name
user.is_admin?

user = User.new user.assign_attributes({ :name => 'Josh', :is_admin => true }, :without_protection => true) user.name
user.is_admin?

Source: show

def assign_attributes(new_attributes, options = {}) return unless new_attributes

attributes = new_attributes.stringify_keys multi_parameter_attributes = [] @mass_assignment_options = options

unless options[:without_protection] attributes = sanitize_for_mass_assignment(attributes, mass_assignment_role) end

attributes.each do |k, v| if k.include?("(") multi_parameter_attributes << [ k, v ] elsif respond_to?("#{k}=") send("#{k}=", v) else raise(UnknownAttributeError, "unknown attribute: #{k}") end end

@mass_assignment_options = nil assign_multiparameter_attributes(multi_parameter_attributes) end

attribute_for_inspect(attr_name)

Returns an #inspect-like string for the value of the attributeattr_name. String attributes are truncated upto 50 characters, and Date and Time attributes are returned in the:db format. Other attributes return the value of#inspect without modification.

person = Person.create!(:name => "David Heinemeier Hansson " * 3)

person.attribute_for_inspect(:name)

person.attribute_for_inspect(:created_at)

Source: show

def attribute_for_inspect(attr_name) value = read_attribute(attr_name)

if value.is_a?(String) && value.length > 50 "#{value[0..50]}...".inspect elsif value.is_a?(Date) || value.is_a?(Time) %Q("#{value.to_s(:db)}") else value.inspect end end

attribute_names()

Returns an array of names for the attributes available on this object.

Source: show

def attribute_names @attributes.keys end

attribute_present?(attribute)

Returns true if the specified attribute has been set by the user or by a database load and is neither nil nor empty? (the latter only applies to objects that respond to empty?, most notably Strings).

Source: show

def attribute_present?(attribute) !_read_attribute(attribute).blank? end

attributes()

Returns a hash of all the attributes with their names as keys and the values of the attributes as values.

Source: show

def attributes Hash[@attributes.map { |name, _| [name, read_attribute(name)] }] end

attributes=(new_attributes, guard_protected_attributes = nil)

Allows you to set all the attributes at once by passing in a hash with keys matching the attribute names (which again matches the column names).

If any attributes are protected by either attr_protected orattr_accessible then only settable attributes will be assigned.

The guard_protected_attributes argument is now deprecated, use the assign_attributes method if you want to bypass mass-assignment security.

class User < ActiveRecord::Base attr_protected :is_admin end

user = User.new user.attributes = { :username => 'Phusion', :is_admin => true } user.username
user.is_admin?

Source: show

def attributes=(new_attributes, guard_protected_attributes = nil) unless guard_protected_attributes.nil? message = "the use of 'guard_protected_attributes' will be removed from the next minor release of rails, " + "if you want to bypass mass-assignment security then look into using assign_attributes" ActiveSupport::Deprecation.warn(message) end

return unless new_attributes.is_a?(Hash)

if guard_protected_attributes == false assign_attributes(new_attributes, :without_protection => true) else assign_attributes(new_attributes) end end

cache_key()

Returns a cache key that can be used to identify this record.

Examples

Product.new.cache_key
Product.find(5).cache_key Person.find(5).cache_key

Source: show

def cache_key case when new_record? "#{self.class.model_name.cache_key}/new" when timestamp = self[:updated_at] timestamp = timestamp.utc.to_s(:number) "#{self.class.model_name.cache_key}/#{id}-#{timestamp}" else "#{self.class.model_name.cache_key}/#{id}" end end

column_for_attribute(name)

Returns the column object for the named attribute.

Source: show

def column_for_attribute(name) self.class.columns_hash[name.to_s] end

connection()

Returns the connection currently associated with the class. This can also be used to “borrow” the connection to do database work that isn’t easily done without going straight to SQL.

Source: show

def connection self.class.connection end

encode_with(coder)

Populate coder with attributes about this record that should be serialized. The structure of coder defined in this method is guaranteed to match the structure of coder passed to theinit_with method.

Example:

class Post < ActiveRecord::Base end coder = {} Post.new.encode_with(coder) coder

Source: show

def encode_with(coder) coder['attributes'] = attributes end

freeze()

Freeze the attributes hash such that associations are still accessible, even on destroyed records.

Source: show

def freeze @attributes.freeze; self end

frozen?()

Returns true if the attributes hash has been frozen.

Source: show

def frozen? @attributes.frozen? end

has_attribute?(attr_name)

Returns true if the given attribute is in the attributes hash

Source: show

def has_attribute?(attr_name) @attributes.has_key?(attr_name.to_s) end

hash()

Delegates to id in order to allow two records of the same type and id to work with something like:

[ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ]

init_with(coder)

Initialize an empty model object from coder.coder must contain the attributes necessary for initializing an empty model object. For example:

class Post < ActiveRecord::Base end

post = Post.allocate post.init_with('attributes' => { 'title' => 'hello world' }) post.title

Source: show

def init_with(coder) @attributes = coder['attributes'] @relation = nil

set_serialized_attributes

@attributes_cache, @previously_changed, @changed_attributes = {}, {}, {} @association_cache = {} @aggregation_cache = {} @readonly = @destroyed = @marked_for_destruction = false @new_record = false run_callbacks :find run_callbacks :initialize

self end

initialize_dup(other)

Duped objects have no id assigned and are treated as new records. Note that this is a “shallow” copy as it copies the object’s attributes only, not its associations. The extent of a “deep” copy is application specific and is therefore left to the application to implement according to its need. The dup method does not preserve the timestamps (created|updated)_(at|on).

Source: show

def initialize_dup(other) cloned_attributes = other.clone_attributes(:read_attribute_before_type_cast) cloned_attributes.delete(self.class.primary_key)

@attributes = cloned_attributes

_run_after_initialize_callbacks if respond_to?(:_run_after_initialize_callbacks)

@changed_attributes = {} attributes_from_column_definition.each do |attr, orig_value| @changed_attributes[attr] = orig_value if field_changed?(attr, orig_value, @attributes[attr]) end

@aggregation_cache = {} @association_cache = {} @attributes_cache = {} @new_record = true

ensure_proper_type populate_with_current_scope_attributes clear_timestamp_attributes end

inspect()

Returns the contents of the record as a nicely formatted string.

Source: show

def inspect attributes_as_nice_string = self.class.column_names.collect { |name| if has_attribute?(name) "#{name}: #{attribute_for_inspect(name)}" end }.compact.join(", ") "#<#{self.class} #{attributes_as_nice_string}>" end

readonly!()

Marks this record as read only.

Source: show

def readonly! @readonly = true end

readonly?()

Returns true if the record is read only. Records loaded through joins with piggy-back attributes will be marked as read only since they cannot be saved.

Source: show

def readonly? @readonly end

to_param()

Returns a String, which Action Pack uses for constructing an URL to this object. The default implementation returns this record’s id as a String, or nil if this record’s unsaved.

For example, suppose that you have a User model, and that you have aresources :users route. Normally, user_path will construct a path with the user object’s ‘id’ in it:

user = User.find_by_name('Phusion') user_path(user)

You can override to_param in your model to makeuser_path construct a path using the user’s name instead of the user’s id:

class User < ActiveRecord::Base def to_param
name end end

user = User.find_by_name('Phusion') user_path(user)

Source: show

def to_param

id && id.to_s end

Instance Protected methods

clone_attribute_value(reader_method, attribute_name)

Source: show

def clone_attribute_value(reader_method, attribute_name) value = send(reader_method, attribute_name) value.duplicable? ? value.clone : value rescue TypeError, NoMethodError value end

clone_attributes(reader_method = :read_attribute, attributes = {})

Source: show

def clone_attributes(reader_method = :read_attribute, attributes = {}) attribute_names.each do |name| attributes[name] = clone_attribute_value(reader_method, name) end attributes end

mass_assignment_options()

Source: show

def mass_assignment_options @mass_assignment_options ||= {} end

mass_assignment_role()

Source: show

def mass_assignment_role mass_assignment_options[:as] || :default end