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/README.html for more insight.
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 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 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 and authenticate_safely_simply both will sanitize the user_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.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 })
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 read_attribute(attr_name) and write_attribute(attr_name, value) 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 * 60)
end
def length
read_attribute(:length) / 60
end
end
You can alternatively use self[:attribute]=(value) and self[:attribute] instead of write_attribute(:attribute, value) and read_attribute(:attribute) as a shorter form.
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? # => true anonymous = User.new(:name => "") anonymous.name? # => false
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 a balance attribute, you can call account.balance_before_type_cast or account.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 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_ or find_all_by_, so you get finders like Person.find_by_user_name, Person.find_all_by_last_name, Payment.find_by_transaction_id. So instead of writing Person.find(:first, :conditions => ["user_name = ?", user_name]), you just do Person.find_by_user_name(user_name). And instead of writing Person.find(:all, :conditions => ["last_name = ?", last_name]), you just do Person.find_all_by_last_name(last_name).
It‘s also possible to use multiple attributes in the same find by separating them with "and", so you get finders like Person.find_by_user_name_and_password or even Payment.find_by_purchaser_and_state_and_country. So instead of writing Person.find(:first, :conditions => ["user_name = ? AND password = ?", user_name, password]), you just do Person.find_by_user_name_and_password(user_name, password).
It‘s even possible to use all the additional parameters to find. For example, the full interface for Payment.find_all_by_amount is actually Payment.find_all_by_amount(amount, options). And the full interface to Person.find_by_user_name is actually Person.find_by_user_name(user_name, options). So you could call Payment.find_all_by_amount(50, :order => "created_on").
The same dynamic finder style can be used to create the object if it doesn‘t already exist. This dynamic finder is called with find_or_create_by_ and will return the object if it already exists and otherwise creates it, then returns it. 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")
Use the find_or_initialize_by_ finder if you want to return a new record without saving it first. 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.
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 descendent 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
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 Base.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.find(:first, "name = ‘37signals’") 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
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 Course.establish_connection and Course *and all 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.
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.
| VALID_FIND_OPTIONS | = | [ :conditions, :include, :joins, :limit, :offset, :order, :select, :readonly, :group, :from, :lock ] |
| set_table_name | -> | table_name= |
| set_primary_key | -> | primary_key= |
| set_inheritance_column | -> | inheritance_column= |
| set_sequence_name | -> | sequence_name= |
| sanitize_sql_for_conditions | -> | sanitize_sql |
| sanitize_sql_hash_for_conditions | -> | sanitize_sql_hash |
| sanitize_sql | -> | sanitize_conditions |
| abstract_class | [RW] | Set this to true if this is an abstract class (see abstract_class?). |
Overwrite the default class equality method to provide support for association proxies.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1204
1204: def ===(object)
1205: object.is_a?(self)
1206: end
Returns whether this class is a base AR class. If A is a base class and B descends from A, then B.base_class will return B.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1220
1220: def abstract_class?
1221: abstract_class == true
1222: end
Similar to the attr_protected macro, this protects attributes of your model from mass-assignment, such as new(attributes) and attributes=(attributes) however, it does it in the opposite way. This locks all attributes and only allows access to the attributes specified. Assignment to attributes not in this list will be ignored and need to be set using the direct writer methods instead. This is meant to protect sensitive attributes from being overwritten by URL/form hackers. If you‘d rather start from an all-open default and restrict attributes as needed, have a look at attr_protected.
*attributes A comma separated list of symbols that represent columns not to be 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"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 853
853: def attr_accessible(*attributes)
854: write_inheritable_attribute("attr_accessible", Set.new(attributes.map(&:to_s)) + (accessible_attributes || []))
855: end
Attributes named in this macro are protected from mass-assignment, such as new(attributes) and attributes=(attributes). Their assignment will simply be ignored. Instead, you can use the direct writer methods to do assignment. This is meant to protect sensitive attributes from being overwritten by URL/form hackers. Example:
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.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 819
819: def attr_protected(*attributes)
820: write_inheritable_attribute("attr_protected", Set.new(attributes.map(&:to_s)) + (protected_attributes || []))
821: end
Attributes listed as readonly can be set for a new record, but will be ignored in database updates afterwards.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 863
863: def attr_readonly(*attributes)
864: write_inheritable_attribute("attr_readonly", Set.new(attributes.map(&:to_s)) + (readonly_attributes || []))
865: end
Returns the base AR subclass that this class descends from. If A extends AR::Base, A.base_class will return A. If B descends from A through some arbitrarily deep hierarchy, B.base_class will return A.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1211
1211: def base_class
1212: class_of_active_record_descendant(self)
1213: end
Log and benchmark multiple statements in a single block. Example:
Project.benchmark("Creating project") do
project = Project.create("name" => "stuff")
project.create_manager("name" => "David")
project.milestones << Milestone.find(:all)
end
The benchmark is only recorded if the current level of the logger matches the log_level, which makes it easy to include benchmarking statements in production software that will remain inexpensive because the benchmark will only be conducted if the log level is low enough.
The logging of the multiple statements is turned off unless use_silence is set to false.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1184
1184: def benchmark(title, log_level = Logger::DEBUG, use_silence = true)
1185: if logger && logger.level == log_level
1186: result = nil
1187: seconds = Benchmark.realtime { result = use_silence ? silence { yield } : yield }
1188: logger.add(log_level, "#{title} (#{'%.5f' % seconds})")
1189: result
1190: else
1191: yield
1192: end
1193: end
Clears the cache which maps classes to connections.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 84
84: def clear_active_connections!
85: clear_cache!(@@active_connections) do |name, conn|
86: conn.disconnect!
87: end
88: end
Clears the cache which maps classes
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 91
91: def clear_reloadable_connections!
92: if @@allow_concurrency
93: # With concurrent connections @@active_connections is
94: # a hash keyed by thread id.
95: @@active_connections.each do |thread_id, conns|
96: conns.each do |name, conn|
97: if conn.requires_reloading?
98: conn.disconnect!
99: @@active_connections[thread_id].delete(name)
100: end
101: end
102: end
103: else
104: @@active_connections.each do |name, conn|
105: if conn.requires_reloading?
106: conn.disconnect!
107: @@active_connections.delete(name)
108: end
109: end
110: end
111: end
Returns an array of column names as strings.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1092
1092: def column_names
1093: @column_names ||= columns.map { |column| column.name }
1094: end
Returns an array of column objects for the table associated with this class.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1078
1078: def columns
1079: unless @columns
1080: @columns = connection.columns(table_name, "#{name} Columns")
1081: @columns.each {|column| column.primary = column.name == primary_key}
1082: end
1083: @columns
1084: end
Returns true if a connection that‘s accessible to this class has already been opened.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 268
268: def self.connected?
269: active_connections[active_connection_name] ? true : false
270: end
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.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 73
73: def connection
74: if @active_connection_name && (conn = active_connections[@active_connection_name])
75: conn
76: else
77: # retrieve_connection sets the cache key.
78: conn = retrieve_connection
79: active_connections[@active_connection_name] = conn
80: end
81: 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.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1098
1098: def content_columns
1099: @content_columns ||= columns.reject { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column }
1100: 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.
sql: An SQL statement which should return a count query from the database, see the example below
Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 729
729: def count_by_sql(sql)
730: sql = sanitize_conditions(sql)
731: connection.select_value(sql, "#{name} Count").to_i
732: 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.
# Create a single new object
User.create(:first_name => 'Jamie')
# Create an Array of new objects
User.create([{:first_name => 'Jamie'}, {:first_name => 'Jeremy'}])
# File vendor/rails/activerecord/lib/active_record/base.rb, line 567
567: def create(attributes = nil)
568: if attributes.is_a?(Array)
569: attributes.collect { |attr| create(attr) }
570: else
571: object = new(attributes)
572: object.save
573: object
574: end
575: 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.
counter_name The name of the field that should be decremented id The id of the object that should be decremented
# Decrement the post_count column for the record with an id of 5 DiscussionBoard.decrement_counter(:post_count, 5)
# File vendor/rails/activerecord/lib/active_record/base.rb, line 797
797: def decrement_counter(counter_name, id)
798: update_counters(id, counter_name => -1)
799: end
Delete an object (or multiple objects) where the id given matches the primary_key. A SQL DELETE command is executed on the database which means that no callbacks are fired off running this. This is an efficient method of deleting records that don‘t need cleaning up after or other actions to be taken.
Objects are not instantiated with this method.
id Can be either an Integer or an Array of Integers
# Delete a single object Todo.delete(1) # Delete multiple objects todos = [1,2,3] Todo.delete(todos)
# File vendor/rails/activerecord/lib/active_record/base.rb, line 622
622: def delete(id)
623: delete_all([ "#{connection.quote_column_name(primary_key)} IN (?)", id ])
624: end
Deletes the records matching conditions without instantiating the records first, and hence not calling the destroy method and invoking callbacks. This is a single SQL query, much more efficient than destroy_all.
conditions Conditions are specified the same way as with find method.
Post.delete_all "person_id = 5 AND (category = 'Something' OR category = 'Else')"
This deletes the affected posts all at once with a single DELETE query. If you need to destroy dependent associations or call your before_ or after_destroy callbacks, use the destroy_all method instead.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 712
712: def delete_all(conditions = nil)
713: sql = "DELETE FROM #{quoted_table_name} "
714: add_conditions!(sql, conditions, scope(:find))
715: connection.delete(sql, "#{name} Delete all")
716: end
True if this isn‘t a concrete subclass needing a STI type condition.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1134
1134: def descends_from_active_record?
1135: if superclass.abstract_class?
1136: superclass.descends_from_active_record?
1137: else
1138: superclass == Base || !columns_hash.include?(inheritance_column)
1139: end
1140: end
Destroy an object (or multiple objects) that has the given id, the object is instantiated first, therefore all callbacks and filters are fired off before the object is deleted. This method is less efficient than ActiveRecord#delete but allows cleanup methods and other actions to be run.
This essentially finds the object (or multiple objects) with the given id, creates a new object from the attributes, and then calls destroy on it.
id Can be either an Integer or an Array of Integers
# Destroy a single object Todo.destroy(1) # Destroy multiple objects todos = [1,2,3] Todo.destroy(todos)
# File vendor/rails/activerecord/lib/active_record/base.rb, line 645
645: def destroy(id)
646: id.is_a?(Array) ? id.each { |id| destroy(id) } : find(id).destroy
647: end
Destroys the records matching conditions by instantiating each record and calling the destroy method. This means at least 2*N database queries to destroy N records, so avoid destroy_all if you are deleting many records. If you want to simply delete records without worrying about dependent associations or callbacks, use the much faster delete_all method instead.
conditions Conditions are specified the same way as with find method.
Person.destroy_all "last_login < '2004-04-04'"
This loads and destroys each person one by one, including its dependent associations and before_ and after_destroy callbacks.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 694
694: def destroy_all(conditions = nil)
695: find(:all, :conditions => conditions).each { |object| object.destroy }
696: end
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.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 204
204: def self.establish_connection(spec = nil)
205: case spec
206: when nil
207: raise AdapterNotSpecified unless defined? RAILS_ENV
208: establish_connection(RAILS_ENV)
209: when ConnectionSpecification
210: clear_active_connection_name
211: @active_connection_name = name
212: @@defined_connections[name] = spec
213: when Symbol, String
214: if configuration = configurations[spec.to_s]
215: establish_connection(configuration)
216: else
217: raise AdapterNotSpecified, "#{spec} database is not configured"
218: end
219: else
220: spec = spec.symbolize_keys
221: unless spec.key?(:adapter) then raise AdapterNotSpecified, "database configuration does not specify adapter" end
222:
223: begin
224: require 'rubygems'
225: gem "activerecord-#{spec[:adapter]}-adapter"
226: require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
227: rescue LoadError
228: begin
229: require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
230: rescue LoadError
231: raise "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{$!})"
232: end
233: end
234:
235: adapter_method = "#{spec[:adapter]}_connection"
236: if !respond_to?(adapter_method)
237: raise AdapterNotFound, "database configuration specifies nonexistent #{spec[:adapter]} adapter"
238: end
239:
240: remove_connection
241: establish_connection(ConnectionSpecification.new(spec, adapter_method))
242: end
243: end
Checks whether a record exists in the database that matches conditions given. These conditions can either be a single integer representing a primary key id to be found, or a condition to be matched like using ActiveRecord#find.
The id_or_conditions parameter can be an Integer or a String if you want to search the primary key column of the table for a matching id, or if you‘re looking to match against a condition you can use an Array or a Hash.
Possible gotcha: You can‘t pass in a condition as a string e.g. "name = ‘Jamie’", this would be sanitized and then queried against the primary key column as "id = ‘name = \’Jamie"
Person.exists?(5)
Person.exists?('5')
Person.exists?(:name => "David")
Person.exists?(['name LIKE ?', "%#{query}%"])
# File vendor/rails/activerecord/lib/active_record/base.rb, line 551
551: def exists?(id_or_conditions)
552: !find(:first, :select => "#{quoted_table_name}.#{primary_key}",
553: :conditions => expand_id_conditions(id_or_conditions)).nil?
554: end
Find operates with three different retrieval approaches:
All approaches accept an options hash as their last parameter. The options are:
Person.find(1) # returns the object for ID = 1 Person.find(1, 2, 6) # returns an array for objects with IDs in (1, 2, 6) Person.find([7, 17]) # returns an array for objects with IDs in (7, 17) Person.find([1]) # returns an array for the object with ID = 1 Person.find(1, :conditions => "administrator = 1", :order => "created_on DESC")
Note that returned records may not be in the same order as the ids you provide since database rows are unordered. Give an explicit :order to ensure the results are sorted.
Examples for find first:
Person.find(:first) # returns the first object fetched by SELECT * FROM people Person.find(:first, :conditions => [ "user_name = ?", user_name]) Person.find(:first, :order => "created_on DESC", :offset => 5)
Examples for find all:
Person.find(:all) # returns an array of objects for all the rows fetched by SELECT * FROM people Person.find(:all, :conditions => [ "category IN (?)", categories], :limit => 50) Person.find(:all, :offset => 10, :limit => 10) Person.find(:all, :include => [ :account, :friends ]) Person.find(:all, :group => "category")
Example for find with a lock. Imagine two concurrent transactions: each will read person.visits == 2, add 1 to it, and save, resulting in two saves of person.visits = 3. By locking the row, the second transaction has to wait until the first is finished; we get the expected person.visits == 4.
Person.transaction do
person = Person.find(1, :lock => true)
person.visits += 1
person.save!
end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 496
496: def find(*args)
497: options = args.extract_options!
498: validate_find_options(options)
499: set_readonly_option!(options)
500:
501: case args.first
502: when :first then find_initial(options)
503: when :all then find_every(options)
504: else find_from_ids(args, options)
505: end
506: end
Executes a custom sql query against your database and returns all the results. The results will be returned as an array with columns requested encapsulated as attributes of the model you call this method from. If you call +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
# 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"}>, ...]
# File vendor/rails/activerecord/lib/active_record/base.rb, line 531
531: def find_by_sql(sql)
532: connection.select_all(sanitize_sql(sql), "#{name} Load").collect! { |record| instantiate(record) }
533: 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.
counter_name The name of the field that should be incremented id The id of the object that should be incremented
# Increment the post_count column for the record with an id of 5 DiscussionBoard.increment_counter(:post_count, 5)
# File vendor/rails/activerecord/lib/active_record/base.rb, line 780
780: def increment_counter(counter_name, id)
781: update_counters(id, counter_name => 1)
782: end
Defines the column name for use with single table inheritance — can be set in subclasses like so: self.inheritance_column = "type_id"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 973
973: def inheritance_column
974: @inheritance_column ||= "type".freeze
975: end
Returns a string like ‘Post id:integer, title:string, body:text‘
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1148
1148: def inspect
1149: if self == Base
1150: super
1151: elsif abstract_class?
1152: "#{super}(abstract)"
1153: elsif table_exists?
1154: attr_list = columns.map { |c| "#{c.name}: #{c.type}" } * ', '
1155: "#{super}(#{attr_list})"
1156: else
1157: "#{super}(Table doesn't exist)"
1158: end
1159: end
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.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1921
1921: def initialize(attributes = nil)
1922: @attributes = attributes_from_column_definition
1923: @attributes_cache = {}
1924: @new_record = true
1925: ensure_proper_type
1926: self.attributes = attributes unless attributes.nil?
1927: self.class.send(:scope, :create).each { |att,value| self.send("#{att}=", value) } if self.class.send(:scoped?, :create)
1928: result = yield self if block_given?
1929: callback(:after_initialize) if respond_to_without_attributes?(:after_initialize)
1930: result
1931: end
Defines the primary key field — can be overridden in subclasses. Overwriting will negate any effect of the primary_key_prefix_type setting, though.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 955
955: def primary_key
956: reset_primary_key
957: end
Returns an array of all the attributes that have been specified as readonly.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 868
868: def readonly_attributes
869: read_inheritable_attribute("attr_readonly")
870: end
Remove the connection for this class. This will close the active connection and the defined connection (if they exist). The result can be used as an argument for establish_connection, for easily re-establishing the connection.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 276
276: def self.remove_connection(klass=self)
277: spec = @@defined_connections[klass.name]
278: konn = active_connections[klass.name]
279: @@defined_connections.delete_if { |key, value| value == spec }
280: active_connections.delete_if { |key, value| value == konn }
281: konn.disconnect! if konn
282: spec.config if spec
283: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 47
47: def self.require_mysql
48: # Include the MySQL driver if one hasn't already been loaded
49: unless defined? Mysql
50: begin
51: require_library_or_gem 'mysql'
52: rescue LoadError => cannot_require_mysql
53: # Use the bundled Ruby/MySQL driver if no driver is already in place
54: begin
55: ActiveRecord::Base.logger.info(
56: "WARNING: You're using the Ruby-based MySQL library that ships with Rails. This library is not suited for production. " +
57: "Please install the C-based MySQL library instead (gem install mysql)."
58: ) if ActiveRecord::Base.logger
59:
60: require 'active_record/vendor/mysql'
61: rescue LoadError
62: raise cannot_require_mysql
63: end
64: end
65: end
66:
67: # Define Mysql::Result.all_hashes
68: MysqlCompat.define_all_hashes_method!
69: end
Resets all the cached information about columns, which will cause them to be reloaded on the next request.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1117
1117: def reset_column_information
1118: generated_methods.each { |name| undef_method(name) }
1119: @column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @generated_methods = @inheritance_column = nil
1120: 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.
attr_name The field name that should be serialized class_name Optional, class name that the object type should be equal to
# Serialize a preferences attribute
class User
serialize :preferences
end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 887
887: def serialize(attr_name, class_name = Object)
888: serialized_attributes[attr_name.to_s] = class_name
889: end
Returns a hash of all the attributes that have been specified for serialization as keys and their class restriction as values.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 892
892: def serialized_attributes
893: read_inheritable_attribute("attr_serialized") or write_inheritable_attribute("attr_serialized", {})
894: end
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.
Example:
class Project < ActiveRecord::Base
set_inheritance_column do
original_inheritance_column + "_id"
end
end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1027
1027: def set_inheritance_column(value = nil, &block)
1028: define_attr_method :inheritance_column, value, &block
1029: end
Sets the name of the primary key column to use to the given value, or (if the value is nil or false) to the value returned by the given block.
Example:
class Project < ActiveRecord::Base
set_primary_key "sysid"
end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1011
1011: def set_primary_key(value = nil, &block)
1012: define_attr_method :primary_key, value, &block
1013: end
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.
Example:
class Project < ActiveRecord::Base
set_sequence_name "projectseq" # default would have been "project_seq"
end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1048
1048: def set_sequence_name(value = nil, &block)
1049: define_attr_method :sequence_name, value, &block
1050: 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.
Example:
class Project < ActiveRecord::Base
set_table_name "project"
end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 997
997: def set_table_name(value = nil, &block)
998: define_attr_method :table_name, value, &block
999: end
Silences the logger for the duration of the block.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1196
1196: def silence
1197: old_logger_level, logger.level = logger.level, Logger::ERROR if logger
1198: yield
1199: ensure
1200: logger.level = old_logger_level if logger
1201: end
Indicates whether the table associated with this class exists
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1062
1062: def table_exists?
1063: if connection.respond_to?(:tables)
1064: connection.tables.include? table_name
1065: else
1066: # if the connection adapter hasn't implemented tables, there are two crude tests that can be
1067: # used - see if getting column info raises an error, or if the number of columns returned is zero
1068: begin
1069: reset_column_information
1070: columns.size > 0
1071: rescue ActiveRecord::StatementInvalid
1072: false
1073: end
1074: end
1075: end
Guesses the table name (in forced lower-case) based on the name of the class in the inheritance hierarchy descending directly from ActiveRecord. So if the hierarchy looks like: Reply < Message < ActiveRecord, 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
# File vendor/rails/activerecord/lib/active_record/base.rb, line 928
928: def table_name
929: reset_table_name
930: end
Updates an object (or multiple objects) and saves it to the database, if validations pass. The resulting object is returned whether the object was saved successfully to the database or not.
id This should be the id or an array of ids to be updated attributes This should be a Hash of attributes to be set on the object, or an array of Hashes.
# Updating one record:
Person.update(15, {:user_name => 'Samuel', :group => 'expert'})
# Updating multiple records:
people = { 1 => { "first_name" => "David" }, 2 => { "first_name" => "Jeremy"} }
Person.update(people.keys, people.values)
# File vendor/rails/activerecord/lib/active_record/base.rb, line 593
593: def update(id, attributes)
594: if id.is_a?(Array)
595: idx = -1
596: id.collect { |id| idx += 1; update(id, attributes[idx]) }
597: else
598: object = find(id)
599: object.update_attributes(attributes)
600: object
601: end
602: end
Updates all records with details given if they match a set of conditions supplied, limits and order can also be supplied.
updates A String of column and value pairs that will be set on any records that match conditions conditions An SQL fragment like "administrator = 1" or [ "user_name = ?", username ].
See conditions in the intro for more info.
options Additional options are :limit and/or :order, see the examples for usage.
# Update all billing objects with the 3 different attributes given
Billing.update_all( "category = 'authorized', approved = 1, author = 'David'" )
# Update records that match our conditions
Billing.update_all( "author = 'David'", "title LIKE '%Rails%'" )
# Update records that match our conditions but limit it to 5 ordered by date
Billing.update_all( "author = 'David'", "title LIKE '%Rails%'",
:order => 'created_at', :limit => 5 )
# File vendor/rails/activerecord/lib/active_record/base.rb, line 670
670: def update_all(updates, conditions = nil, options = {})
671: sql = "UPDATE #{table_name} SET #{sanitize_sql_for_assignment(updates)} "
672: scope = scope(:find)
673: add_conditions!(sql, conditions, scope)
674: add_order!(sql, options[:order], scope)
675: add_limit!(sql, options, scope)
676: connection.update(sql, "#{name} Update")
677: 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:
id The id of the object you wish to update a counter on 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
# 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
# File vendor/rails/activerecord/lib/active_record/base.rb, line 757
757: def update_counters(id, counters)
758: updates = counters.inject([]) { |list, (counter_name, increment)|
759: sign = increment < 0 ? "-" : "+"
760: list << "#{connection.quote_column_name(counter_name)} = #{connection.quote_column_name(counter_name)} #{sign} #{increment.abs}"
761: }.join(", ")
762: update_all(updates, "#{connection.quote_column_name(primary_key)} = #{quote_value(id)}")
763: end
Returns the class descending directly from ActiveRecord in the inheritance hierarchy.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1755
1755: def class_of_active_record_descendant(klass)
1756: if klass.superclass == Base || klass.superclass.abstract_class?
1757: klass
1758: elsif klass.superclass.nil?
1759: raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
1760: else
1761: class_of_active_record_descendant(klass.superclass)
1762: end
1763: end
Returns the class type of the record using the current module as a prefix. So descendents of MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1745
1745: def compute_type(type_name)
1746: modularized_name = type_name_with_module(type_name)
1747: begin
1748: class_eval(modularized_name, __FILE__, __LINE__)
1749: rescue NameError
1750: class_eval(type_name, __FILE__, __LINE__)
1751: end
1752: end
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'"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1835
1835: def sanitize_sql_array(ary)
1836: statement, *values = ary
1837: if values.first.is_a?(Hash) and statement =~ /:\w+/
1838: replace_named_bind_variables(statement, values.first)
1839: elsif statement.include?('?')
1840: replace_bind_variables(statement, values)
1841: else
1842: statement % values.collect { |value| connection.quote_string(value.to_s) }
1843: end
1844: end
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'"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1787
1787: def sanitize_sql_for_assignment(assignments)
1788: case assignments
1789: when Array; sanitize_sql_array(assignments)
1790: when Hash; sanitize_sql_hash_for_assignment(assignments)
1791: else assignments
1792: end
1793: end
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'"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1775
1775: def sanitize_sql_for_conditions(condition)
1776: case condition
1777: when Array; sanitize_sql_array(condition)
1778: when Hash; sanitize_sql_hash_for_conditions(condition)
1779: else condition
1780: end
1781: end
Sanitizes a hash of attribute/value pairs into SQL conditions for a SET clause.
{ :status => nil, :group_id => 1 }
# => "status = NULL , group_id = 1"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1826
1826: def sanitize_sql_hash_for_assignment(attrs)
1827: conditions = attrs.map do |attr, value|
1828: "#{connection.quote_column_name(attr)} = #{quote_bound_value(value)}"
1829: end.join(', ')
1830: end
Sanitizes a hash of attribute/value pairs into SQL conditions for a WHERE clause.
{ :name => "foo'bar", :group_id => 4 }
# => "name='foo''bar' and group_id= 4"
{ :status => nil, :group_id => [1,2,3] }
# => "status IS NULL and group_id IN (1,2,3)"
{ :age => 13..18 }
# => "age BETWEEN 13 AND 18"
{ 'other_records.id' => 7 }
# => "`other_records`.`id` = 7"
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1804
1804: def sanitize_sql_hash_for_conditions(attrs)
1805: conditions = attrs.map do |attr, value|
1806: attr = attr.to_s
1807:
1808: # Extract table name from qualified attribute names.
1809: if attr.include?('.')
1810: table_name, attr = attr.split('.', 2)
1811: table_name = connection.quote_table_name(table_name)
1812: else
1813: table_name = quoted_table_name
1814: end
1815:
1816: "#{table_name}.#{connection.quote_column_name(attr)} #{attribute_condition(value)}"
1817: end.join(' AND ')
1818:
1819: replace_bind_variables(conditions, expand_range_bind_variables(attrs.values))
1820: end
Works like with_scope, but discards any nested properties.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1700
1700: def with_exclusive_scope(method_scoping = {}, &block)
1701: with_scope(method_scoping, :overwrite, &block)
1702: end
Scope parameters to method calls within the block. Takes a hash of method_name => parameters hash. method_name may be :find or :create. :find parameters may include the :conditions, :joins, :include, :offset, :limit, and :readonly options. :create parameters are an attributes hash.
class Article < ActiveRecord::Base
def self.create_with_scope
with_scope(:find => { :conditions => "blog_id = 1" }, :create => { :blog_id => 1 }) do
find(1) # => SELECT * from articles WHERE blog_id = 1 AND id = 1
a = create(1)
a.blog_id # => 1
end
end
end
In nested scopings, all previous parameters are overwritten by the innermost rule, with the exception of :conditions and :include options in :find, which are merged.
class Article < ActiveRecord::Base
def self.find_with_scope
with_scope(:find => { :conditions => "blog_id = 1", :limit => 1 }, :create => { :blog_id => 1 }) do
with_scope(:find => { :limit => 10})
find(:all) # => SELECT * from articles WHERE blog_id = 1 LIMIT 10
end
with_scope(:find => { :conditions => "author_id = 3" })
find(:all) # => SELECT * from articles WHERE blog_id = 1 AND author_id = 3 LIMIT 1
end
end
end
end
You can ignore any previous scopings by using the with_exclusive_scope method.
class Article < ActiveRecord::Base
def self.find_with_exclusive_scope
with_scope(:find => { :conditions => "blog_id = 1", :limit => 1 }) do
with_exclusive_scope(:find => { :limit => 10 })
find(:all) # => SELECT * from articles LIMIT 10
end
end
end
end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1648
1648: def with_scope(method_scoping = {}, action = :merge, &block)
1649: method_scoping = method_scoping.method_scoping if method_scoping.respond_to?(:method_scoping)
1650:
1651: # Dup first and second level of hash (method and params).
1652: method_scoping = method_scoping.inject({}) do |hash, (method, params)|
1653: hash[method] = (params == true) ? params : params.dup
1654: hash
1655: end
1656:
1657: method_scoping.assert_valid_keys([ :find, :create ])
1658:
1659: if f = method_scoping[:find]
1660: f.assert_valid_keys(VALID_FIND_OPTIONS)
1661: set_readonly_option! f
1662: end
1663:
1664: # Merge scopings
1665: if action == :merge && current_scoped_methods
1666: method_scoping = current_scoped_methods.inject(method_scoping) do |hash, (method, params)|
1667: case hash[method]
1668: when Hash
1669: if method == :find
1670: (hash[method].keys + params.keys).uniq.each do |key|
1671: merge = hash[method][key] && params[key] # merge if both scopes have the same key
1672: if key == :conditions && merge
1673: hash[method][key] = [params[key], hash[method][key]].collect{ |sql| "( %s )" % sanitize_sql(sql) }.join(" AND ")
1674: elsif key == :include && merge
1675: hash[method][key] = merge_includes(hash[method][key], params[key]).uniq
1676: else
1677: hash[method][key] = hash[method][key] || params[key]
1678: end
1679: end
1680: else
1681: hash[method] = params.merge(hash[method])
1682: end
1683: else
1684: hash[method] = params
1685: end
1686: hash
1687: end
1688: end
1689:
1690: self.scoped_methods << method_scoping
1691:
1692: begin
1693: yield
1694: ensure
1695: self.scoped_methods.pop
1696: end
1697: end
Returns true if the comparison_object is the same object, or is of the same type and has the same id.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2187
2187: def ==(comparison_object)
2188: comparison_object.equal?(self) ||
2189: (comparison_object.instance_of?(self.class) &&
2190: comparison_object.id == id &&
2191: !comparison_object.new_record?)
2192: end
Returns the value of the attribute identified by attr_name after it has been typecast (for example, "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)). (Alias for the protected read_attribute method).
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2094
2094: def [](attr_name)
2095: read_attribute(attr_name)
2096: end
Updates the attribute identified by attr_name with the specified value. (Alias for the protected write_attribute method).
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2100
2100: def []=(attr_name, value)
2101: write_attribute(attr_name, value)
2102: end
Format attributes nicely for inspect.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2152
2152: def attribute_for_inspect(attr_name)
2153: value = read_attribute(attr_name)
2154:
2155: if value.is_a?(String) && value.length > 50
2156: "#{value[0..50]}...".inspect
2157: elsif value.is_a?(Date) || value.is_a?(Time)
2158: %("#{value.to_s(:db)}")
2159: else
2160: value.inspect
2161: end
2162: end
Returns an array of names for the attributes available on this object sorted alphabetically.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2177
2177: def attribute_names
2178: @attributes.keys.sort
2179: end
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).
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2166
2166: def attribute_present?(attribute)
2167: value = read_attribute(attribute)
2168: !value.blank?
2169: end
Returns a hash of all the attributes with their names as keys and clones of their objects as values.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2126
2126: def attributes(options = nil)
2127: attributes = clone_attributes :read_attribute
2128:
2129: if options.nil?
2130: attributes
2131: else
2132: if except = options[:except]
2133: except = Array(except).collect { |attribute| attribute.to_s }
2134: except.each { |attribute_name| attributes.delete(attribute_name) }
2135: attributes
2136: elsif only = options[:only]
2137: only = Array(only).collect { |attribute| attribute.to_s }
2138: attributes.delete_if { |key, value| !only.include?(key) }
2139: attributes
2140: else
2141: raise ArgumentError, "Options does not specify :except or :only (#{options.keys.inspect})"
2142: end
2143: end
2144: end
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). Sensitive attributes can be protected from this form of mass-assignment by using the attr_protected macro. Or you can alternatively specify which attributes can be accessed with the attr_accessible macro. Then all the attributes not included in that won‘t be allowed to be mass-assigned.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2109
2109: def attributes=(new_attributes, guard_protected_attributes = true)
2110: return if new_attributes.nil?
2111: attributes = new_attributes.dup
2112: attributes.stringify_keys!
2113:
2114: multi_parameter_attributes = []
2115: attributes = remove_attributes_protected_from_mass_assignment(attributes) if guard_protected_attributes
2116:
2117: attributes.each do |k, v|
2118: k.include?("(") ? multi_parameter_attributes << [ k, v ] : send(k + "=", v)
2119: end
2120:
2121: assign_multiparameter_attributes(multi_parameter_attributes)
2122: end
Returns a hash of cloned attributes before typecasting and deserialization.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2147
2147: def attributes_before_type_cast
2148: clone_attributes :read_attribute_before_type_cast
2149: end
Returns an instance of the specified klass with the attributes of the current record. This is mostly useful in relation to single-table inheritance structures where you want a subclass to appear as the superclass. This can be used along with record identification in Action Pack to allow, say, Client < Company to do something like render :partial => @client.becomes(Company) to render that instance using the companies/company partial instead of clients/client.
Note: The new instance will share a link to the same attributes as the original class. So any change to the attributes in either instance will affect the other.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2015
2015: def becomes(klass)
2016: returning klass.new do |became|
2017: became.instance_variable_set("@attributes", @attributes)
2018: became.instance_variable_set("@attributes_cache", @attributes_cache)
2019: became.instance_variable_set("@new_record", new_record?)
2020: end
2021: end
Returns a clone of the record that hasn‘t been assigned an id yet and is treated as a new record. Note that this is a "shallow" clone: it copies the object‘s attributes only, not its associations. The extent of a "deep" clone is application-specific and is therefore left to the application to implement according to its need.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2000
2000: def clone
2001: attrs = self.attributes_before_type_cast
2002: attrs.delete(self.class.primary_key)
2003: record = self.class.new
2004: record.send :instance_variable_set, '@attributes', attrs
2005: record
2006: end
Returns the column object for the named attribute.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2182
2182: def column_for_attribute(name)
2183: self.class.columns_hash[name.to_s]
2184: end
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.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 173
173: def connection
174: self.class.connection
175: end
Initializes the attribute to zero if nil and subtracts one. Only makes sense for number-based attributes. Returns self.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2057
2057: def decrement(attribute)
2058: self[attribute] ||= 0
2059: self[attribute] -= 1
2060: self
2061: end
Decrements the attribute and saves the record.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2064
2064: def decrement!(attribute)
2065: decrement(attribute).update_attribute(attribute, self[attribute])
2066: end
Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can‘t be persisted).
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1983
1983: def destroy
1984: unless new_record?
1985: connection.delete "DELETE FROM \#{self.class.quoted_table_name}\nWHERE \#{connection.quote_column_name(self.class.primary_key)} = \#{quoted_id}\n", "#{self.class.name} Destroy"
1986: end
1987:
1988: freeze
1989: end
Delegates to ==
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2195
2195: def eql?(comparison_object)
2196: self == (comparison_object)
2197: end
Freeze the attributes hash such that associations are still accessible, even on destroyed records.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2206
2206: def freeze
2207: @attributes.freeze; self
2208: end
Returns true if the attributes hash has been frozen.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2211
2211: def frozen?
2212: @attributes.frozen?
2213: end
Returns true if the given attribute is in the attributes hash
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2172
2172: def has_attribute?(attr_name)
2173: @attributes.has_key?(attr_name.to_s)
2174: end
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) ] # => [ Person.find(1) ]
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2201
2201: def hash
2202: id.hash
2203: end
A model instance‘s primary key is always available as model.id whether you name it the default ‘id’ or set it to something else.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1935
1935: def id
1936: attr_name = self.class.primary_key
1937: column = column_for_attribute(attr_name)
1938:
1939: self.class.send(:define_read_method, :id, attr_name, column)
1940: # now that the method exists, call it
1941: self.send attr_name.to_sym
1942:
1943: end
Sets the primary ID.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1960
1960: def id=(value)
1961: write_attribute(self.class.primary_key, value)
1962: end
Initializes the attribute to zero if nil and adds one. Only makes sense for number-based attributes. Returns self.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2045
2045: def increment(attribute)
2046: self[attribute] ||= 0
2047: self[attribute] += 1
2048: self
2049: end
Increments the attribute and saves the record.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2052
2052: def increment!(attribute)
2053: increment(attribute).update_attribute(attribute, self[attribute])
2054: end
Returns the contents of the record as a nicely formatted string.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2227
2227: def inspect
2228: attributes_as_nice_string = self.class.column_names.collect { |name|
2229: if has_attribute?(name) || new_record?
2230: "#{name}: #{attribute_for_inspect(name)}"
2231: end
2232: }.compact.join(", ")
2233: "#<#{self.class} #{attributes_as_nice_string}>"
2234: end
Returns true if this object hasn‘t been saved yet — that is, a record for the object doesn‘t exist yet.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1965
1965: def new_record?
1966: @new_record
1967: end
Marks this record as read only.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2222
2222: def readonly!
2223: @readonly = true
2224: end
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.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2217
2217: def readonly?
2218: @readonly == true
2219: end
Reloads the attributes of this object from the database. The optional options argument is passed to find when reloading so you may do e.g. record.reload(:lock => true) to reload the same record with an exclusive row lock.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2083
2083: def reload(options = nil)
2084: clear_aggregation_cache
2085: clear_association_cache
2086: @attributes.update(self.class.find(self.id, options).instance_variable_get('@attributes'))
2087: @attributes_cache = {}
2088: self
2089: end
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1971
1971: def save
1972: create_or_update
1973: end
Attempts to save the record, but instead of just returning false if it couldn‘t happen, it raises a RecordNotSaved exception
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1977
1977: def save!
1978: create_or_update || raise(RecordNotSaved)
1979: end
Enables Active Record objects to be used as URL parameters in Action Pack automatically.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 1946
1946: def to_param
1947: # We can't use alias_method here, because method 'id' optimizes itself on the fly.
1948: (id = self.id) ? id.to_s : nil # Be sure to stringify the id for routes
1949: end
Turns an attribute that‘s currently true into false and vice versa. Returns self.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2069
2069: def toggle(attribute)
2070: self[attribute] = !send("#{attribute}?")
2071: self
2072: end
Toggles the attribute and saves the record.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2075
2075: def toggle!(attribute)
2076: toggle(attribute).update_attribute(attribute, self[attribute])
2077: end
Updates a single attribute and saves the record. This is especially useful for boolean flags on existing records. Note: This method is overwritten by the Validation module that‘ll make sure that updates made with this method aren‘t subjected to validation checks. Hence, attributes can be updated even if the full object isn‘t valid.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2026
2026: def update_attribute(name, value)
2027: send(name.to_s + '=', value)
2028: save
2029: end
Updates all the attributes from the passed-in Hash and saves the record. If the object is invalid, the saving will fail and false will be returned.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2033
2033: def update_attributes(attributes)
2034: self.attributes = attributes
2035: save
2036: end
Updates an object just like Base.update_attributes but calls save! instead of save so an exception is raised if the record is invalid.
# File vendor/rails/activerecord/lib/active_record/base.rb, line 2039
2039: def update_attributes!(attributes)
2040: self.attributes = attributes
2041: save!
2042: end