一个活动有很多艺术家，一个艺术家有很多活动。艺术家和活动的连接模型是一种表演。我想将艺术家添加到活动中。
除了在创建新事件时我在连接表中获得重复条目时，这是有效的。这会在其他地方引起问题。
event.rb
validates_presence_of :name, :location
has_many :performances, :dependent => :destroy
has_many :artists, :through => :performances
accepts_nested_attributes_for :artists, :reject_if => proc {|a| a['name'].blank?}
# accepts_nested_attributes_for :performances, :reject_if => proc { |a| a['artist_id'].blank? }
artist.rb
has_many :performances
has_many :events, :through => :performances
has_attached_file :photo, :styles => { :small => "150x150>" },
:url => "/images/artists/:id/:style/:basename.:extension",
:path => ":rails_root/public/images/artists/:id/:style/:basename.:extension"
# validates_attachment_presence :photo
validates_attachment_size :photo, :less_than => 5.megabytes
validates_attachment_content_type :photo, :content_type => ['image/jpeg', 'image/png']
validates_presence_of :name
has_many :mixes
performance.rb
belongs_to :artist
belongs_to :event
events_controller.rb
def new
@event = Event.new
@event.artists.build
respond_to do |format|
format.html # new.html.erb
format.xml { render :xml => @event }
end
end
def create
@event = Event.new(params[:event])
respond_to do |format|
if @event.save
flash[:notice] = 'Event was successfully created.'
format.html { redirect_to(admin_events_url) }
format.xml { render :xml => @event, :status => :created, :location => @event }
else
format.html { render :action => "new" }
format.xml { render :xml => @event.errors, :status => :unprocessable_entity }
end
end
end
_form.html.erb
<% form_for([:admin,@event]) do |f| %>
<p>
<%= f.label :name %><br />
<%= f.text_field :name %>
</p>
<p>
<%= f.label :location %><br/>
<%= f.text_field :location %>
</p>
<p>
<%= f.label :date %><br />
<%= f.date_select :date %>
</p>
<p>
<%= f.label :description %><br />
<%= f.text_area :description %>
</p>
<% f.fields_for :artists do |builder| %>
<p>
<%= builder.label :name, "Artist"%><br/>
<%= builder.text_field :name %><br/>
</p>
<% end %>
<p>
<%= f.submit 'Submit' %> <%= link_to 'Cancel', admin_events_path %>
</p>
<% end %>
输出第二个accepts_nested_attributes_for注释掉
Processing Admin::EventsController#create (for 127.0.0.1 at 2010-06-15 21:10:24) [POST]
Parameters: {"commit"=>"Submit", "authenticity_token"=>"KigiyUNIE2iYTwo59lf7SClbG9Dxge7WEWDDd08OLEc=", "event"=>{"name"=>"test event", "artists_attributes"=>{"0"=>{"name"=>"test artist"}}, "date(1i)"=>"2010", "location"=>"some location", "date(2i)"=>"6", "date(3i)"=>"16", "description"=>"blah"}}
User Columns (2.4ms) SHOW FIELDS FROM `users`
User Load (0.3ms) SELECT * FROM `users` WHERE (`users`.`id` = 13) LIMIT 1
Event Columns (1.2ms) SHOW FIELDS FROM `events`
Artist Columns (1.4ms) SHOW FIELDS FROM `artists`
SQL (0.1ms) BEGIN
Event Create (0.3ms) INSERT INTO `events` (`name`, `created_at`, `location`, `updated_at`, `date`, `description`) VALUES('test event', '2010-06-16 04:10:24', 'some location', '2010-06-16 04:10:24', '2010-06-16', 'blah')
Artist Create (0.2ms) INSERT INTO `artists` (`name`, `created_at`, `photo_file_size`, `updated_at`, `photo_file_name`, `photo_content_type`, `photo_updated_at`, `bio`) VALUES('test artist', '2010-06-16 04:10:24', NULL, '2010-06-16 04:10:24', NULL, NULL, NULL, NULL)
[paperclip] Saving attachments.
Performance Columns (1.1ms) SHOW FIELDS FROM `performances`
Performance Create (0.2ms) INSERT INTO `performances` (`event_id`, `artist_id`) VALUES(10, 22)
Performance Create (0.1ms) INSERT INTO `performances` (`event_id`, `artist_id`) VALUES(10, 22)
SQL (0.4ms) COMMIT
Redirected to http://localhost:3000/admin/events
Completed in 97ms (DB: 8) | 302 Found [http://localhost/admin/events]
答案 0 :(得分：0)
我刚刚使用您提供的代码创建了一个快速测试rails应用程序，结果如下：
Processing EventsController#create (for 192.168.1.2 at 2010-06-16 00:33:05) [POST]
Parameters: {"commit"=>"Create", "authenticity_token"=>"R8lKqeTIbRQ5Ft8K+TNMNusCh4qmnOv8xxSIi25MMNE=", "event"=>{"name"=>"Event", "artists_attributes"=>{"0"=>{"name"=>"Me"}}, "date(1i)"=>"2010", "location"=>"nowhere", "date(2i)"=>"6", "date(3i)"=>"16", "description"=>"Test Event"}}
Event Create (0.4ms) INSERT INTO "events" ("name", "location", "created_at", "updated_at", "date", "description") VALUES('Event', 'nowhere', '2010-06-16 04:33:05', '2010-06-16 04:33:05', '2010-06-16', 'Test Event')
Artist Create (12.3ms) INSERT INTO "artists" ("name", "created_at", "updated_at") VALUES('Me', '2010-06-16 04:33:05', '2010-06-16 04:33:05')
Performance Create (0.2ms) INSERT INTO "performances" ("name", "created_at", "event_id", "updated_at", "artist_id") VALUES(NULL, '2010-06-16 04:33:05', 1, '2010-06-16 04:33:05', 1)
Redirected to http://192.168.1.5:3000/events/1
Completed in 251ms (DB: 13) | 302 Found [http://192.168.1.5/events]
您运行的是什么版本的Rails？
您是否尝试创建一个干净的测试应用程序以查看它是否有效？
可能有宝石或某个插件导致问题。我正在使用SQLite3运行2.3.8。
我没有得到你显示的所有额外输出，这可能是MySQL特定的与has_many :through关系有关的东西，但这也是值得关注的。
这是我的架构供参考：
create_table "artists", :force => true do |t|
t.string "name"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "events", :force => true do |t|
t.string "name"
t.string "location"
t.date "date"
t.text "description"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "performances", :force => true do |t|
t.string "name"
t.integer "artist_id"
t.integer "event_id"
t.datetime "created_at"
t.datetime "updated_at"
end
答案 1 :(得分：0)
通过将Rails更新到最新版本2.3.8解决了这个问题。这似乎是2.3.5中的错误。