section_id：无 当它应该是 section_id：1
section_id: nil WHEN IT SHOULD BE section_id: 1
我正在关注 Kevin Skoglund 的 LYNDA.COM 教程。当我遇到问题时，我正在关注 "Many-to-many" 协会：Rich”视频。最后一行我 运行 (section.section_edits)
结果如下：
SectionEdit id: 6, admin_user_id: 1, section_id: nil, ...
但是 Kevin 在教程中的结果是：
SectionEdit id: 1, admin_user_id: 1, section_id: 1, ...
显然我已经回过头几次试图找出我的错误，这就是为什么我的 SectionEdit id: 与他的不同。但我的问题是：为什么我的 section_id: nil
编辑：2016 年 9 月 25 日
我在命令提示符中输入了 section.errors，但不完全理解控制台的响应。 @AlterLagos
irb(main):004:0> section = Section.create(:name => "Section One", :position => 1)
(0.5ms) BEGIN
(1.0ms) ROLLBACK
=> #<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>
irb(main):005:0> section.errors
=> #<ActiveModel::Errors:0x6340fe0 @base=#<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>, @messages={:page=>["must exist"]}, @details={:page=>[{:error=>:blank}]}>
下面是我的控制台和关联的 classes。谢谢！
我的命令提示符
C:\Users\David\My Documents\sites\simple_cms>rails console
Loading development environment (Rails 5.0.0.1)
irb(main):001:0> me = AdminUser.find(1)
AdminUser Load (4.0ms) SELECT `admin_users`.* FROM `admin_users` WHERE`admin_users`.`id` = 1 LIMIT 1
=> #<AdminUser id: 1, first_name: "David", last_name: "Boyette", email: "", hashed_password: nil, created_at: "2016-09-08 02:52:57", updated_at: "2016-09-08 02:52:57", username: "dboyette", salt: nil>
irb(main):002:0> me.section_edits
SectionEdit Load (3.5ms) SELECT `section_edits`.* FROM `section_edits` WHERE `section_edits`.`admin_user_id` = 1
=> #<ActiveRecord::Associations::CollectionProxy [#<SectionEdit id: 1, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-09 01:19:08", updated_at: "2016-09-09 01:19:08">, #<SectionEdit id: 2, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-10 00:05:56", updated_at: "2016-09-10 00:05:56">, #<SectionEdit id: 3, admin_user_id: 1, section_id: nil, summary: "Ch-ch-ch-changes", created_at: "2016-09-10 00:09:39", updated_at: "2016-09-10 00:09:39">, #<SectionEdit id: 4, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-17 03:32:13", updated_at: "2016-09-17 03:32:13">, #<SectionEdit id: 5, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-18 00:48:40", updated_at: "2016-09-18 00:48:40">]>
irb(main):003:0> section = Section.create(:name => "Section One", :position => 1)
(1.0ms) BEGIN
(1.0ms) ROLLBACK
=> #<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>
irb(main):004:0> section.section_edits => #<ActiveRecord::Associations::CollectionProxy []>
irb(main):005:0> edit = SectionEdit.new
=> #<SectionEdit id: nil, admin_user_id: nil, section_id: nil, summary: nil, created_at: nil, updated_at: nil>
irb(main):006:0> edit.summary = "Test edit"
=> "Test edit"
irb(main):007:0> section.section_edits << edit
=> #<ActiveRecord::Associations::CollectionProxy [#<SectionEdit id: nil, admin_user_id: nil, section_id: nil, summary: "Test edit", created_at: nil, updated_at: nil>]>
irb(main):008:0> edit.editor = me
=> #<AdminUser id: 1, first_name: "David", last_name: "Boyette", email: "", hashed_password: nil, created_at: "2016-09-08 02:52:57", updated_at: "2016-09-08 02:52:57", username: "dboyette", salt: nil>
irb(main):009:0> edit.save
(1.5ms) BEGIN
SQL (3.0ms) INSERT INTO `section_edits` (`admin_user_id`, `summary`, `created_at`, `updated_at`) VALUES (1, 'Test edit', '2016-09-18 01:44:41', '2016-09-18 01:44:41')
(69.3ms) COMMIT
=> true
irb(main):010:0> section.section_edits
=> #<ActiveRecord::Associations::CollectionProxy [#<SectionEdit id: 6, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-18 01:44:41", updated_at: "2016-09-18 01:44:41">]>
irb(main):011:0>
section.rb
class Section < ApplicationRecord
belongs_to :page
has_many :section_edits
has_many :editors, :through => :section_edits, :class_name => "AdminUser"
结束
部分迁移
class CreateSections < ActiveRecord::Migration[5.0]
默认更改
create_table :sections do |t|
t.integer "page_id"
# same as t.reference :page
t.string "name"
t.integer "position"
t.boolean "visible", :default => false
t.string "content_type"
t.text "content"
t.timestamps
end
add_index("sections", "page_id")
结束
结束
section_edit.rb
class SectionEdit < ApplicationRecord
belongs_to :editor, :class_name => "AdminUser", :foreign_key => 'admin_user_id'
belongs_to :section
结束
section_edits迁移
class CreateSectionEdits < ActiveRecord::Migration[5.0]
默认更改
create_table :section_edits 做 |t|
t.references :admin_user
t.references :section
t.string "summary"
t.timestamps
end
add_index :section_edits, ['admin_user_id', 'section_id']
结束
结束
型号：page.rb
`class 页面 < ApplicationRecord
belongs_to :subject
has_many :sections
has_and_belongs_to_many :editors, :class_name => "AdminUser"
结束
`
控制器：页面
class PagesController < ApplicationController
end
迁移：页面
`class 创建页面 < ActiveRecord::Migration[5.0]
定义更改
create_table :页数 |t|
t.integer "subject_id"
# same as t.references :subject
t.string "name"
t.string "permalink"
t.integer "position"
t.boolean "visible", :default => false
t.timestamps
end
add_index("pages", "subject_id")
add_index("pages", "permalink")
结束
结束`
检查你的控制台，显然这里有问题：
irb(main):003:0> section = Section.create(:name => "Section One", :position => 1)
(1.0ms) BEGIN
(1.0ms) ROLLBACK
=> #<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>
如您所见，创建部分后由于验证错误而回滚，因此部分对象具有 id: nil。我想这是因为您没有在问题代码中包含验证，但在创建该部分后，您可以使用 section.errors 轻松检查控制台中的错误并查看问题所在。
只是想添加一些信息以防其他人遇到同样的问题。
Alter Lagos 是正确的，该部分有一个限制，它必须分配一个页面。这就是导致调用失败的原因。
要创建部分对象，请执行以下操作：（它不在视频中）。
page = Page.first
然后创建栏目并传入页面。
section = Section.create(:name => "Section One", :position => 1, :page => page)
在 section.rb 文件中 -
做了
belongs_to:page, {:optional => true}
然后在 rails 控制台 运行-
section = Section.create(:name => "Section One", :position => 1)
干杯
我正在关注 Kevin Skoglund 的 LYNDA.COM 教程。当我遇到问题时，我正在关注 "Many-to-many" 协会：Rich”视频。最后一行我 运行 (section.section_edits)
结果如下：
SectionEdit id: 6, admin_user_id: 1, section_id: nil, ...
但是 Kevin 在教程中的结果是：
SectionEdit id: 1, admin_user_id: 1, section_id: 1, ...
显然我已经回过头几次试图找出我的错误，这就是为什么我的 SectionEdit id: 与他的不同。但我的问题是：为什么我的 section_id: nil
编辑：2016 年 9 月 25 日
我在命令提示符中输入了 section.errors，但不完全理解控制台的响应。 @AlterLagos
irb(main):004:0> section = Section.create(:name => "Section One", :position => 1)
(0.5ms) BEGIN
(1.0ms) ROLLBACK
=> #<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>
irb(main):005:0> section.errors
=> #<ActiveModel::Errors:0x6340fe0 @base=#<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>, @messages={:page=>["must exist"]}, @details={:page=>[{:error=>:blank}]}>
下面是我的控制台和关联的 classes。谢谢！
我的命令提示符
C:\Users\David\My Documents\sites\simple_cms>rails console
Loading development environment (Rails 5.0.0.1)
irb(main):001:0> me = AdminUser.find(1)
AdminUser Load (4.0ms) SELECT `admin_users`.* FROM `admin_users` WHERE`admin_users`.`id` = 1 LIMIT 1
=> #<AdminUser id: 1, first_name: "David", last_name: "Boyette", email: "", hashed_password: nil, created_at: "2016-09-08 02:52:57", updated_at: "2016-09-08 02:52:57", username: "dboyette", salt: nil>
irb(main):002:0> me.section_edits
SectionEdit Load (3.5ms) SELECT `section_edits`.* FROM `section_edits` WHERE `section_edits`.`admin_user_id` = 1
=> #<ActiveRecord::Associations::CollectionProxy [#<SectionEdit id: 1, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-09 01:19:08", updated_at: "2016-09-09 01:19:08">, #<SectionEdit id: 2, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-10 00:05:56", updated_at: "2016-09-10 00:05:56">, #<SectionEdit id: 3, admin_user_id: 1, section_id: nil, summary: "Ch-ch-ch-changes", created_at: "2016-09-10 00:09:39", updated_at: "2016-09-10 00:09:39">, #<SectionEdit id: 4, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-17 03:32:13", updated_at: "2016-09-17 03:32:13">, #<SectionEdit id: 5, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-18 00:48:40", updated_at: "2016-09-18 00:48:40">]>
irb(main):003:0> section = Section.create(:name => "Section One", :position => 1)
(1.0ms) BEGIN
(1.0ms) ROLLBACK
=> #<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>
irb(main):004:0> section.section_edits => #<ActiveRecord::Associations::CollectionProxy []>
irb(main):005:0> edit = SectionEdit.new
=> #<SectionEdit id: nil, admin_user_id: nil, section_id: nil, summary: nil, created_at: nil, updated_at: nil>
irb(main):006:0> edit.summary = "Test edit"
=> "Test edit"
irb(main):007:0> section.section_edits << edit
=> #<ActiveRecord::Associations::CollectionProxy [#<SectionEdit id: nil, admin_user_id: nil, section_id: nil, summary: "Test edit", created_at: nil, updated_at: nil>]>
irb(main):008:0> edit.editor = me
=> #<AdminUser id: 1, first_name: "David", last_name: "Boyette", email: "", hashed_password: nil, created_at: "2016-09-08 02:52:57", updated_at: "2016-09-08 02:52:57", username: "dboyette", salt: nil>
irb(main):009:0> edit.save
(1.5ms) BEGIN
SQL (3.0ms) INSERT INTO `section_edits` (`admin_user_id`, `summary`, `created_at`, `updated_at`) VALUES (1, 'Test edit', '2016-09-18 01:44:41', '2016-09-18 01:44:41')
(69.3ms) COMMIT
=> true
irb(main):010:0> section.section_edits
=> #<ActiveRecord::Associations::CollectionProxy [#<SectionEdit id: 6, admin_user_id: 1, section_id: nil, summary: "Test edit", created_at: "2016-09-18 01:44:41", updated_at: "2016-09-18 01:44:41">]>
irb(main):011:0>
section.rb
class Section < ApplicationRecord
belongs_to :page
has_many :section_edits
has_many :editors, :through => :section_edits, :class_name => "AdminUser"
结束
部分迁移
class CreateSections < ActiveRecord::Migration[5.0]
默认更改 create_table :sections do |t|
t.integer "page_id"
# same as t.reference :page
t.string "name"
t.integer "position"
t.boolean "visible", :default => false
t.string "content_type"
t.text "content"
t.timestamps
end
add_index("sections", "page_id")
结束 结束
section_edit.rb
class SectionEdit < ApplicationRecord
belongs_to :editor, :class_name => "AdminUser", :foreign_key => 'admin_user_id'
belongs_to :section
结束
section_edits迁移
class CreateSectionEdits < ActiveRecord::Migration[5.0]
默认更改 create_table :section_edits 做 |t|
t.references :admin_user
t.references :section
t.string "summary"
t.timestamps
end
add_index :section_edits, ['admin_user_id', 'section_id']
结束 结束
型号：page.rb
`class 页面 < ApplicationRecord
belongs_to :subject
has_many :sections
has_and_belongs_to_many :editors, :class_name => "AdminUser"
结束 `
控制器：页面
class PagesController < ApplicationController
end
迁移：页面
`class 创建页面 < ActiveRecord::Migration[5.0] 定义更改 create_table :页数 |t|
t.integer "subject_id"
# same as t.references :subject
t.string "name"
t.string "permalink"
t.integer "position"
t.boolean "visible", :default => false
t.timestamps
end
add_index("pages", "subject_id")
add_index("pages", "permalink")
结束 结束`
检查你的控制台，显然这里有问题：
irb(main):003:0> section = Section.create(:name => "Section One", :position => 1)
(1.0ms) BEGIN
(1.0ms) ROLLBACK
=> #<Section id: nil, page_id: nil, name: "Section One", position: 1, visible: false, content_type: nil, content: nil, created_at: nil, updated_at: nil>
如您所见，创建部分后由于验证错误而回滚，因此部分对象具有 id: nil。我想这是因为您没有在问题代码中包含验证，但在创建该部分后，您可以使用 section.errors 轻松检查控制台中的错误并查看问题所在。
只是想添加一些信息以防其他人遇到同样的问题。
Alter Lagos 是正确的，该部分有一个限制，它必须分配一个页面。这就是导致调用失败的原因。
要创建部分对象，请执行以下操作：（它不在视频中）。
page = Page.first
然后创建栏目并传入页面。
section = Section.create(:name => "Section One", :position => 1, :page => page)
在 section.rb 文件中 - 做了 belongs_to:page, {:optional => true}
然后在 rails 控制台 运行- section = Section.create(:name => "Section One", :position => 1)
干杯