diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG index 143de8192507c..e82906186ee05 100644 --- a/activerecord/CHANGELOG +++ b/activerecord/CHANGELOG @@ -4,6 +4,12 @@ Wed Sep 7 15:25:02 2011 Aaron Patterson keys are per process id. * lib/active_record/connection_adapters/sqlite_adapter.rb: ditto +* Add first_or_create, first_or_create!, first_or_build and first_or_new methods to Active Record. This is a better approach over the old find_or_create_by dynamic methods because it's clearer which arguments are used to find the record and which are used to create it: + + User.where(:first_name => "Scarlett").first_or_create!(:last_name => "Johansson", :hot => true) + + [Andrés Mejía] + * Support bulk change_table in mysql2 adapter, as well as the mysql one. [Jon Leighton] * If multiple parameters are sent representing a date, and some are blank, the diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb index 374791deb19ee..2979ad1cb348e 100644 --- a/activerecord/lib/active_record/base.rb +++ b/activerecord/lib/active_record/base.rb @@ -442,6 +442,7 @@ class Base class << self # Class methods delegate :find, :first, :first!, :last, :last!, :all, :exists?, :any?, :many?, :to => :scoped + delegate :first_or_create, :first_or_create!, :first_or_new, :first_or_build, :to => :scoped delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, :to => :scoped delegate :find_each, :find_in_batches, :to => :scoped delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins, :where, :preload, :eager_load, :includes, :from, :lock, :readonly, :having, :create_with, :to => :scoped diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb index 15fd1a58c89ce..d3f1347e039d8 100644 --- a/activerecord/lib/active_record/relation.rb +++ b/activerecord/lib/active_record/relation.rb @@ -94,6 +94,49 @@ def create!(*args, &block) scoping { @klass.create!(*args, &block) } end + # Tries to load the first record; if it fails, then create is called with the same arguments as this method. + # + # Expects arguments in the same format as Base.create. + # + # ==== Examples + # # Find the first user named Penélope or create a new one. + # User.where(:first_name => 'Penélope').first_or_create + # # => + # + # # Find the first user named Penélope or create a new one. + # # We already have one so the existing record will be returned. + # User.where(:first_name => 'Penélope').first_or_create + # # => + # + # # Find the first user named Scarlett or create a new one with a particular last name. + # User.where(:first_name => 'Scarlett').first_or_create(:last_name => 'Johansson') + # # => + # + # # Find the first user named Scarlett or create a new one with a different last name. + # # We already have one so the existing record will be returned. + # User.where(:first_name => 'Scarlett').first_or_create do |user| + # user.last_name = "O'Hara" + # end + # # => + def first_or_create(attributes = nil, options = {}, &block) + first || create(attributes, options, &block) + end + + # Like first_or_create but calls create! so an exception is raised if the created record is invalid. + # + # Expects arguments in the same format as Base.create!. + def first_or_create!(attributes = nil, options = {}, &block) + first || create!(attributes, options, &block) + end + + # Like first_or_create but calls new instead of create. + # + # Expects arguments in the same format as Base.new. + def first_or_new(attributes = nil, options = {}, &block) + first || new(attributes, options, &block) + end + alias :first_or_build :first_or_new + def respond_to?(method, include_private = false) arel.respond_to?(method, include_private) || Array.method_defined?(method) || diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb index 87f5b5ee8118b..63879259af74b 100644 --- a/activerecord/test/cases/base_test.rb +++ b/activerecord/test/cases/base_test.rb @@ -278,6 +278,37 @@ def test_create_after_initialize_with_block assert_equal(true, cb.frickinawesome) end + def test_first_or_create + parrot = Bird.first_or_create(:color => 'green', :name => 'parrot') + assert parrot.persisted? + the_same_parrot = Bird.first_or_create(:color => 'yellow', :name => 'macaw') + assert_equal parrot, the_same_parrot + end + + def test_first_or_create_bang + assert_raises(ActiveRecord::RecordInvalid) { Bird.first_or_create! } + parrot = Bird.first_or_create!(:color => 'green', :name => 'parrot') + assert parrot.persisted? + the_same_parrot = Bird.first_or_create!(:color => 'yellow', :name => 'macaw') + assert_equal parrot, the_same_parrot + end + + def test_first_or_new + parrot = Bird.first_or_new(:color => 'green', :name => 'parrot') + assert_kind_of Bird, parrot + assert !parrot.persisted? + assert parrot.new_record? + assert parrot.valid? + end + + def test_first_or_build + parrot = Bird.first_or_build(:color => 'green', :name => 'parrot') + assert_kind_of Bird, parrot + assert !parrot.persisted? + assert parrot.new_record? + assert parrot.valid? + end + def test_load topics = Topic.find(:all, :order => 'id') assert_equal(4, topics.size) diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb index da96afd71899c..b491d6304710a 100644 --- a/activerecord/test/cases/relations_test.rb +++ b/activerecord/test/cases/relations_test.rb @@ -863,6 +863,134 @@ def test_create_bang assert_equal 'hen', hen.name end + def test_first_or_create + parrot = Bird.where(:color => 'green').first_or_create(:name => 'parrot') + assert_kind_of Bird, parrot + assert parrot.persisted? + assert_equal 'parrot', parrot.name + assert_equal 'green', parrot.color + + same_parrot = Bird.where(:color => 'green').first_or_create(:name => 'parakeet') + assert_kind_of Bird, same_parrot + assert same_parrot.persisted? + assert_equal parrot, same_parrot + end + + def test_first_or_create_with_no_parameters + parrot = Bird.where(:color => 'green').first_or_create + assert_kind_of Bird, parrot + assert !parrot.persisted? + assert_equal 'green', parrot.color + end + + def test_first_or_create_with_block + parrot = Bird.where(:color => 'green').first_or_create { |bird| bird.name = 'parrot' } + assert_kind_of Bird, parrot + assert parrot.persisted? + assert_equal 'green', parrot.color + assert_equal 'parrot', parrot.name + + same_parrot = Bird.where(:color => 'green').first_or_create { |bird| bird.name = 'parakeet' } + assert_equal parrot, same_parrot + end + + def test_first_or_create_with_array + several_green_birds = Bird.where(:color => 'green').first_or_create([{:name => 'parrot'}, {:name => 'parakeet'}]) + assert_kind_of Array, several_green_birds + several_green_birds.each { |bird| assert bird.persisted? } + + same_parrot = Bird.where(:color => 'green').first_or_create([{:name => 'hummingbird'}, {:name => 'macaw'}]) + assert_kind_of Bird, same_parrot + assert_equal several_green_birds.first, same_parrot + end + + def test_first_or_create_bang_with_valid_options + parrot = Bird.where(:color => 'green').first_or_create!(:name => 'parrot') + assert_kind_of Bird, parrot + assert parrot.persisted? + assert_equal 'parrot', parrot.name + assert_equal 'green', parrot.color + + same_parrot = Bird.where(:color => 'green').first_or_create!(:name => 'parakeet') + assert_kind_of Bird, same_parrot + assert same_parrot.persisted? + assert_equal parrot, same_parrot + end + + def test_first_or_create_bang_with_invalid_options + assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create!(:pirate_id => 1) } + end + + def test_first_or_create_bang_with_no_parameters + assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create! } + end + + def test_first_or_create_bang_with_valid_block + parrot = Bird.where(:color => 'green').first_or_create! { |bird| bird.name = 'parrot' } + assert_kind_of Bird, parrot + assert parrot.persisted? + assert_equal 'green', parrot.color + assert_equal 'parrot', parrot.name + + same_parrot = Bird.where(:color => 'green').first_or_create! { |bird| bird.name = 'parakeet' } + assert_equal parrot, same_parrot + end + + def test_first_or_create_bang_with_invalid_block + assert_raise(ActiveRecord::RecordInvalid) do + parrot = Bird.where(:color => 'green').first_or_create! { |bird| bird.pirate_id = 1 } + end + end + + def test_first_or_create_with_valid_array + several_green_birds = Bird.where(:color => 'green').first_or_create!([{:name => 'parrot'}, {:name => 'parakeet'}]) + assert_kind_of Array, several_green_birds + several_green_birds.each { |bird| assert bird.persisted? } + + same_parrot = Bird.where(:color => 'green').first_or_create!([{:name => 'hummingbird'}, {:name => 'macaw'}]) + assert_kind_of Bird, same_parrot + assert_equal several_green_birds.first, same_parrot + end + + def test_first_or_create_with_invalid_array + assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create!([ {:name => 'parrot'}, {:pirate_id => 1} ]) } + end + + def test_first_or_new + parrot = Bird.where(:color => 'green').first_or_new(:name => 'parrot') + assert_kind_of Bird, parrot + assert !parrot.persisted? + assert parrot.valid? + assert parrot.new_record? + assert_equal 'parrot', parrot.name + assert_equal 'green', parrot.color + end + + def test_first_or_new_with_no_parameters + parrot = Bird.where(:color => 'green').first_or_new + assert_kind_of Bird, parrot + assert !parrot.persisted? + assert !parrot.valid? + assert parrot.new_record? + assert_equal 'green', parrot.color + end + + def test_first_or_new_with_block + parrot = Bird.where(:color => 'green').first_or_new { |bird| bird.name = 'parrot' } + assert_kind_of Bird, parrot + assert !parrot.persisted? + assert parrot.valid? + assert parrot.new_record? + assert_equal 'green', parrot.color + assert_equal 'parrot', parrot.name + end + + def test_first_or_build_is_alias_for_first_or_new + birds = Bird.scoped + assert birds.respond_to?(:first_or_build) + assert_equal birds.method(:first_or_new), birds.method(:first_or_build) + end + def test_explicit_create_scope hens = Bird.where(:name => 'hen') assert_equal 'hen', hens.new.name diff --git a/railties/guides/source/active_record_querying.textile b/railties/guides/source/active_record_querying.textile index 95a7bfebc3987..7a853db813392 100644 --- a/railties/guides/source/active_record_querying.textile +++ b/railties/guides/source/active_record_querying.textile @@ -1018,23 +1018,84 @@ If you want to find both by name and locked, you can chain these finders togethe WARNING: Up to and including Rails 3.1, when the number of arguments passed to a dynamic finder method is lesser than the number of fields, say Client.find_by_name_and_locked("Ryan"), the behavior is to pass +nil+ as the missing argument. This is *unintentional* and this behavior will be changed in Rails 3.2 to throw an +ArgumentError+. -There's another set of dynamic finders that let you find or create/initialize objects if they aren't found. These work in a similar fashion to the other finders and can be used like +find_or_create_by_first_name(params[:first_name])+. Using this will first perform a find and then create if the find returns +nil+. The SQL looks like this for +Client.find_or_create_by_first_name("Ryan")+: +h3. Find or build a new object + +It's common that you need to find a record or create it if it doesn't exist. You can do that with the +first_or_create+ and +first_or_create!+ methods. + +h4. +first_or_create+ + +The +first_or_create+ method checks whether +first+ returns +nil+ or not. If it does return +nil+, then +create+ is called. This is very powerful when coupled with the +where+ method. Let's see an example. + +Suppose you want to find a client named 'Andy', and if there's none, create one and additionally set his +locked+ attribute to false. You can do so by running: + + +Client.where(:first_name => 'Andy').first_or_create(:locked => false) +# => + + +The SQL generated by this method looks like this: -SELECT * FROM clients WHERE (clients.first_name = 'Ryan') LIMIT 1 +SELECT * FROM clients WHERE (clients.first_name = 'Andy') LIMIT 1 BEGIN -INSERT INTO clients (first_name, updated_at, created_at, orders_count, locked) - VALUES('Ryan', '2008-09-28 15:39:12', '2008-09-28 15:39:12', 0, '0') +INSERT INTO clients (created_at, first_name, locked, orders_count, updated_at) VALUES ('2011-08-30 05:22:57', 'Andy', 0, NULL, '2011-08-30 05:22:57') COMMIT -+find_or_create+'s sibling, +find_or_initialize+, will find an object and if it does not exist will act similarly to calling +new+ with the arguments you passed in. For example: ++first_or_create+ returns either the record that already existed or the new record. In our case, we didn't already have a client named Andy so the record was created an returned. + +The new record might not be saved to the database; that depends on whether validations passed or not (just like +create+). + +It's also worth noting that +first_or_create+ takes into account the arguments of the +where+ method. In the example above we didn't explicitly pass a +:first_name => 'Andy'+ argument to +first_or_create+. However, that was used when creating the new record because it was already passed before to the +where+ method. + +NOTE: On previous versions of Rails you could do a similar thing with the +find_or_create_by+ method. Following our example, you could also run something like +Client.find_or_create_by_first_name(:first_name => "Andy", :locked => false)+. This method still works, but it's encouraged to use +first_or_create+ because it's more explicit on what arguments are used to _find_ the record and what arguments are used to _create_ it, resulting in less confusion overall. + +h4. +first_or_create!+ + +You can also use +first_or_create!+ to raise an exception if the new record is invalid. Validations are not covered on this guide, but let's assume for a moment that you temporarily add + + + validates :orders_count, :presence => true + + +to your +Client+ model. If you try to create a new +Client+ without passing an +orders_count+, the record will be invalid and an exception will be raised: + + +Client.where(:first_name => 'Andy').first_or_create!(:locked => false) +# => ActiveRecord::RecordInvalid: Validation failed: Orders count can't be blank + + +NOTE: Be sure to check the extensive *Active Record Validations and Callbacks Guide* for more information about validations. + +h4. +first_or_new+ + +The +first_or_new+ method will work just like +first_or_create+ but it will not call +create+ but +new+. This means that a new model instance will be created in memory but won't be saved to the database. Continuing with the +first_or_create+ example, we now want the client named 'Nick': + + +nick = Client.where(:first_name => 'Nick').first_or_new(:locked => false) +# => + +nick.persisted? +# => false + +nick.new_record? +# => true + + +Because the object is not yet stored in the database, the SQL generated looks like this: + + +SELECT * FROM clients WHERE (clients.first_name = 'Nick') LIMIT 1 + + +When you want to save it to the database, just call +save+: -client = Client.find_or_initialize_by_first_name('Ryan') +nick.save +# => true -will either assign an existing client object with the name "Ryan" to the client local variable, or initialize a new object similar to calling +Client.new(:first_name => 'Ryan')+. From here, you can modify other fields in client by calling the attribute setters on it: +client.locked = true+ and when you want to write it to the database just call +save+ on it. +Just like you can use *+build+* instead of *+new+*, you can use *+first_or_build+* instead of *+first_or_new+*. h3. Finding by SQL